Global environmental problems
Global environmental problems of our time
Anthropogenic climate change
Annual increase in atmospheric content:
- burning of fossil fuels;
- anthropogenic disturbances of the living conditions of microbial communities of soils in Siberia and North America.
Effects:
- the process of desertification is accelerating (6 million hectares annually in the world);
- climate change in Siberia and Scandinavia;
- the rise in the level of the World Ocean is accelerating (due to the melting of polar ice). Over the past century, the ocean level has risen by 10-12 cm, and by the middle of the XXI century. a rise of 150 cm is predicted.
Thinning of the ozone screen in the stratosphere
Antarctica - 2/3 of the southern continent ozone "hole":
–1% O3 leads to an increase in the incidence of skin cancer by 5–7%, which is 6–9 thousand people in the European territory of the country.
Reasons: emissions of freons (a special group of chlorofluorocarbons), space launches, supersonic flights at high altitudes.
The consequence: an increase and the frequency of cancer, the death of forests and even the death of all terrestrial life on earth.
Environmental pollution
- uncontrolled increase in the number of various pollutants (agriculture, industry, transport, household pollution);
- extensive use of water resources;
- water management construction without taking into account the impact on nature (for example, the problem of the Aral Sea).
Environmental impact of energy production
Acidic precipitation
- reduce the content of nutrients in the leaves (conifers) and increase the removal of minerals from the soil
- reduce the yield
- destroy natural vegetation (forests of Belarus and Ukraine)
- destroy life in freshwater bodies with a pH of 5 or below (in the US, more than 80% of lakes are lifeless)
- convert insoluble compounds in the soil into soluble ones; as a result of soil acidification by compounds of Al, Co and other metals, they accumulate in plants and in water bodies in large quantities
Reduction of biological diversity
Biodiversity (biological diversity) - the diversity of life in all its manifestations. Also, biodiversity is understood as diversity at three levels of organization: genetic diversity (diversity of genes and their variants - alleles), species diversity (diversity of species in ecosystems) and, finally, ecosystem diversity, that is, the diversity of ecosystems themselves.
The reasons for the disappearance of species and the fact that they are becoming rare are divided into two main groups:
1. Direct pursuit, hunting, etc.
2. Disappearance or change, degradation of the habitat.
the main factors threatening vertebrates:
67% - destruction or degradation of habitat;
37% - overexploitation;
19% - the influence of introduced species, i.e. species that have been intentionally or accidentally transported outside the range;
4% - loss, reduction or deterioration of the food supply;
3% - destruction in order to protect agricultural plants, domestic animals, commercial objects;
2% - random loot.
(Figures - the number of species (in%) endangered (the amount exceeds 100% due to the fact that a number of species are threatened by more than one factor)
NUMBER OF THREATED ANIMAL SPECIES
International Red Book:
236 species of mammals;
287 bird species;
119 species of reptiles;
36 types of amphibians.
Demographic problem
The global demographic problem has two parts:
1. fast and poorly controlled population growth in developing countries (the so-called countries of the "Southern region"),
2. the aging of the population of developed countries and many countries with economies in transition (the so-called countries of the "Northern region").
Never in the entire history of mankind has the growth rate of the world's population been so high as in the second half of the 20th century and the beginning of the 21st century. During the period from 1960 to 1999, the world's population doubled (from 3 billion to 6 billion people), and in 2007 it amounted to 6.6 billion people. Although the average annual growth rate of the world's population has decreased from 2.2% in the early 60s. up to 1.5% in the early 2000s, the absolute annual growth increased from 53 million to 80 million people.
The demographic transition from the traditional (high fertility - high mortality - low natural increase) to the modern type of population reproduction (low fertility - low mortality - low natural population growth) ended in developed countries in the first third of the 20th century, and in most countries with economies in transition - in the middle of the last century. At the same time, in the 1950s-1960s, a demographic transition began in a number of countries and regions of the rest of the world, which begins to end only in Latin America, East and Southeast Asia and continues in many countries of Asia, Africa, the Middle and Middle East.
The rapid rates of population growth in comparison with the rates of socio-economic development in these regions lead to an exacerbation of the problems of employment, poverty, food situation, the land issue, a low level of education, and deterioration of the health of the population. The authorities of these countries see the solution (or do not pay attention to these problems) to their demographic problem in the acceleration of economic growth and a simultaneous decrease in the birth rate (an example would be China - a successful solution to the problem).
The main factor influencing the birth rate at the present stage is cultural and civilizational.
In Europe, Japan and a number of CIS countries from the last quarter of the XX century. a demographic crisis is taking place, which is manifested in slow growth and even natural decline and aging of the population, stabilization or reduction of its able-bodied part. Demographic aging (an increase in the proportion of the population over the age of 60 over 12% of the total population, over 65 years of age - over 7%) is a natural process, which is based on the success of medicine, an increase in the quality of life and other factors that contribute to the prolongation of the life of a significant part of the population. population.
With regard to such an aspect of the demographic problem in these countries as the decline in the economically active population, the authorities of many of these countries see it as a solution, primarily in the influx of immigrants from other countries.
Read also:
|
The predominant causes of the loss of species diversity and the degradation of biological resources (and simply LIFE on Earth) are large-scale deforestation and burning of forests, destruction of coral reefs, uncontrolled fishing, excessive destruction of plants and animals, illegal trade in species of wild fauna and flora, use of pesticides, drainage of swamps, air pollution, the use of untouched nature for agricultural purposes and city building.
Forests are inhabited by most of the known terrestrial species, but 45% of the Earth's natural forests have disappeared, mostly deforested over the past century. Despite all efforts, the world's forest area is rapidly declining. Up to 10% of coral reefs - one of the richest ecosystems - have been destroyed, and 1/3 of the rest will die in the next 10-20 years! Coastal mangroves - a vital natural habitat for the young of many animal species - are also threatened, and half of them have already disappeared. Depletion of the ozone layer causes more ultraviolet rays to penetrate the Earth's surface, where they destroy living tissue. Global warming is changing the habitats and distribution of species. Many of them will die if the average annual temperature on Earth rises.
3. Solve the problem. In the fruit fly Drosophila, white-eyed is inherited as a recessive
trait linked to the X chromosome. We crossed a white-eyed female with a red-eyed
male. Determine (in percentage) the number of white-eyed males in the offspring.
1. The structure and function of chromosomes. Chromosomal set of sex and somatic cells in
different organisms.
3. The cycle of substances and the transformation of energy in the biosphere (for example, the cycle of carbon or other elements).
The circulation of substances and the transformation of energy as the basis for the existence of the biosphere. The activity of living organisms in the biosphere is accompanied by the extraction of large amounts of minerals from the environment. After the death of organisms, their constituent chemical elements return to the environment. This is how a biogenic (with the participation of living organisms) circulation of substances in nature arises, that is, the circulation of substances between the lithosphere, atmosphere, hydrosphere and living organisms. The circulation of substances is understood as a repetitive process of transformation and movement of substances in nature, which has a more or less pronounced cyclical character.
All living organisms take part in the circulation of substances, absorbing some substances from the external environment and releasing others into it. Thus, plants consume carbon dioxide, water and mineral salts from the external environment and release oxygen into it. Animals inhale the oxygen released by plants, and eating them assimilate organic substances synthesized from water and carbon dioxide and release carbon dioxide, water and substances from the undigested part of food. When bacteria and fungi decompose dead plants and animals, an additional amount of carbon dioxide is formed, and organic substances are converted into minerals, which enter the soil and are absorbed by plants again. Thus, the atoms of the main chemical elements constantly migrate from one organism to another, from the soil, atmosphere and hydrosphere to living organisms, and from them to the environment, thus replenishing the inanimate matter of the biosphere. These processes are repeated an infinite number of times. So, for example, all atmospheric oxygen passes through living matter in 2 thousand years, all carbon dioxide in 200-300 years.
The continuous circulation of chemical elements in the biosphere along more or less closed paths is called a biogeochemical cycle. The need for such circulation is due to the limited supply of their resources on the planet. To ensure the infinity of life, chemical elements must move in a circle. The cycle of each chemical element is a part of the general grandiose cycle of substances on Earth, that is, all cycles are closely related to each other.
The circulation of substances, like all processes occurring in nature, requires a constant flow of energy. The basis of the biogenic cycle that ensures the existence of life is solar energy. The energy bound in organic substances decreases at the steps of the food chain, because most of it enters the environment in the form of heat or is spent on the implementation of processes occurring in organisms, therefore, the flow of energy and its transformation is observed in the biosphere. Thus, the biosphere can be stable only under the condition of a constant circulation of substances and an influx of solar energy. The water cycle. Water is the most abundant substance in the biosphere. Its main reserves (97.1%) are concentrated in the form of salty-bitter water of the seas and oceans. The rest of the waters are fresh. The waters of glaciers and eternal snows (i.e. water in a solid state) together account for about 2.24% (70% of all fresh water reserves), groundwater - 0.61%, water of lakes and rivers, respectively, 0.016% and 0, 0001%, atmospheric moisture 0.001%. Water in the form of water vapor evaporates from the surface of the seas and oceans and is carried by air currents at various distances. Most of the evaporated water returns as rain to the ocean, and less to land. From land, water in the form of water vapor is lost due to the processes of evaporation from its surface and transpiration by plants. Water is carried into the atmosphere and returns to land or ocean in the form of precipitation. At the same time, river water flows from the continents to the seas and oceans. As you can see, the basis of the global water cycle in the biosphere is provided by physical processes involving the world's oceans. The role of living matter in them, it would seem, is insignificant. However, on continents, the mass of water evaporated by plants and the soil surface plays a major role in the water cycle. So, in various forest zones, the main amount of precipitation is formed from water vapor entering the atmosphere due to total evaporation, and as a result, such zones live, as it were, on their own closed water balance. The amount of water transported by the vegetation cover is very significant. So, a hectare of forest evaporates 20-50 tons of water per day. The role of the vegetation cover is also to retain water by slowing down its runoff, to maintain a constant level of groundwater, etc. Carbon cycle. Carbon is an indispensable chemical element in organic substances of all classes. Green plants play a huge role in the carbon cycle. In the process of photosynthesis, carbon dioxide of the atmosphere and hydrosphere is assimilated by terrestrial and aquatic plants, as well as cyanobacteria, and is converted into carbohydrates. In the process of respiration of all living organisms, the opposite process occurs: the carbon of organic compounds is converted into carbon dioxide. As a result, many tens of billions of tons of carbon are annually involved in the cycle. Thus, two fundamental biological processes - photosynthesis and respiration - determine the circulation of carbon in the biosphere. Marine organisms are another powerful consumer of carbon. They use carbon compounds to build shells, skeletal structures. Subsequently, the remains of dead marine organisms form powerful limestone deposits on the bottom of the seas and oceans. The carbon cycle is not completely closed. Carbon can be released from it for a rather long period in the form of deposits of coal, limestone, peat, sapropels, humus, etc. A person violates the regulated carbon cycle in the course of intensive economic activity. Due to the burning of huge amounts of fossil fuels, the content of carbon dioxide in the atmosphere for the XX century. increased by 25%. The consequence of this may be an increase in the greenhouse effect. The nitrogen cycle. Nitrogen is an essential component of the most important organic compounds: proteins, nucleic acids, ATP, etc. Its main reserves are concentrated in the atmosphere in the form of molecular nitrogen, inaccessible to plants, since they are able to use it only in the form of inorganic compounds. The ways of nitrogen entry into soil and water environment are different. Thus, a small amount of nitrogenous compounds is formed in the atmosphere during thunderstorms. Together with rainwater, they enter the aquatic or soil environment. A small part of nitrogenous compounds comes from volcanic eruptions. Only some prokaryotic organisms are capable of direct fixation of atmospheric molecular nitrogen: bacteria and cyanobacteria. The most active nitrogen fixers are nodule bacteria that inhabit the root cells of leguminous plants. They convert molecular nitrogen into compounds that can be assimilated by plants. After the plants die off and the nodules decompose, the soil is enriched with organic and mineral forms of nitrogen. Cyanobacteria play a significant role in the enrichment of the aquatic environment with nitrogenous compounds. Nitrogen-containing organic substances of dead plants and animals, as well as urea and uric acid secreted by animals and fungi, are broken down by putrefactive (ammonifying) bacteria to ammonia. The bulk of the resulting ammonia is oxidized by nitrifying bacteria to nitrites and nitrates, after which it is reused by plants. Some of the ammonia escapes into the atmosphere and, together with carbon dioxide and other gaseous substances, performs the function of retaining the planet's heat. Various forms of nitrogenous compounds of soil and aquatic environment can be reduced by some types of bacteria to oxides and molecular nitrogen. This process is called denitrification. Its result is the depletion of soil and water with nitrogen compounds and saturation of the atmosphere with molecular nitrogen. The processes of nitrification and denitrification were completely balanced up to the period of intensive human use of nitrogen fertilizers in order to obtain large yields of agricultural plants. Thus, the role of living organisms in the nitrogen cycle is the main one. Evolution of the biosphere. The modern structure of the biosphere and the boundaries of the habitat of modern organisms were formed gradually. They are the result of a long history of the Earth, from its inception to the present. The evidence for the development of the biosphere is abundant and indisputable. These are primarily the fossil remains of ancient organisms. Studying them, scientists have established the main stages in the history of the development of organic life on the planet. It is assumed that over the entire history of the biosphere, it was inhabited, replacing each other, by about 500 million species of organisms. The most important stage in the development of life on Earth is closely related to the change in the oxygen content in the atmosphere and the formation of the ozone screen. Ancient phototrophic cyanobacteria saturated the primary ocean with oxygen, thanks to which aquatic organisms were able to carry out aerobic respiration. The entry of oxygen into the atmosphere led to the formation of a powerful ozone layer that absorbs short-wave ultraviolet radiation. The formation of the ozone layer allowed organisms to come to land and inhabit its various habitats. This became possible when the oxygen content in the atmosphere reached 10% of its current concentration. By the end of the Paleozoic, in the Permian period, the concentration of oxygen in the atmosphere reached its present level. Each period in the development of the biosphere was characterized by a complex of environmental conditions and living organisms characteristic of it. In the Cenozoic era, the formation of a man took place, who at the beginning of his evolution fit well into nature. Passing to active labor activity, a person escaped from the captivity of natural natural dependence. Over time, human society has increased its impact on the natural environment. At present, in the era of scientific and technological revolution, which coincided with the rapid growth of the world's population (demographic explosion), human activity is comparable in its consequences to the natural environment with the action of the most powerful natural phenomena.
3. Solve the problem. In dogs, black coat color dominates over brown. From
crosses of a black female with a brown male, 4 black and 3
brown puppy. Determine the genotypes of the parents and offspring.
1. Concepts about the gene. Genetic code, its properties.
The genetic code is a way inherent in all living organisms to encode the amino acid sequence of proteins using a sequence of nucleotides. In DNA, four nucleotides are used - adenine (A), guanine (G), cytosine (C), thymine (T), which in Russian literature are designated by the letters A, G, C and T. These letters make up the alphabet of the genetic code. In RNA, the same nucleotides are used, with the exception of thymine, which is replaced by a similar nucleotide - uracil, which is denoted by the letter U (Y in Russian literature). In DNA and RNA molecules, nucleotides are arranged in chains and, thus, sequences of genetic letters are obtained. The Genetic Code There are 20 different amino acids used in nature to build proteins. Each protein is a chain or several chains of amino acids in a strictly defined sequence. This sequence determines the structure of the protein, and therefore all of its biological properties. The set of amino acids is also universal for almost all living organisms. The implementation of genetic information in living cells (that is, the synthesis of the protein encoded by the gene) is carried out using two matrix processes: transcription (that is, synthesis of RNA and RNA on a DNA matrix) and translation of the genetic code into an amino acid sequence (synthesis of a polypeptide chain on an mRNA matrix). Three consecutive nucleotides are enough to encode 20 amino acids, as well as a stop signal, which means the end of the protein sequence. A set of three nucleotides is called a triplet. Accepted abbreviations corresponding to amino acids and codons are shown in the figure.
Properties of the genetic code.
Triplet - the significant unit of the code is a combination of three nucleotides (triplet, or codon). Continuity - there are no punctuation marks between triplets, that is, information is read continuously. Non-overlapping - the same nucleotide cannot be simultaneously included in two or more triplets. (Not true for some overlapping genes of viruses, mitochondria and bacteria that code for multiple frameshift proteins.)
Unambiguous - a certain codon corresponds to only one amino acid. (The property is not universal. The UGA codon in Euplotes crassus encodes two amino acids - cysteine and selenocysteine). Degeneracy (redundancy) - several codons can correspond to the same amino acid. Versatility - the genetic code works in the same way in organisms of different levels of complexity - from viruses to humans (genetic engineering methods are based on this).
2. The history of the development of evolutionary ideas. Evaluation of the works of K. Linnaeus, Zh.B. Lamarck,
Charles Darwin.
1. Evolution according to Lamarck was presented as a continuous forward movement from lower forms of life to higher ones. To explain the varying degrees of complexity of the structure observed among modern species, he allowed the constant spontaneous generation of life: the ancestors of more highly organized forms were born earlier and therefore their descendants went further along the path of progress. Lamarck believed that the aspiration for perfection and progressive development, which was originally inherent in every living organism, was the mechanism of evolution. How and why this desire arose, Lamarck did not explain and did not even consider this issue worthy of attention. According to Darwin: Natural selection of individual isolated varieties in different conditions of existence gradually leads to divergence (divergence) of the characteristics of these varieties and, ultimately, to speciation.
2. Lamarck believed that changes arising under the influence of the environment can be inherited. He believed that increased exercise of organs leads to their enlargement, and failure to exercise leads to degeneration. So Lamarck explained the long nose of the anteater by the fact that his ancestors from generation to generation exercised their nose, sniffing in search of ants. He considered the reduction of eyes in moles to be a consequence of their failure to exercise in a number of generations. Neither Lamarck nor his followers asked the question, why, in fact, intense exercise, the use of an organ must necessarily lead to its improvement, improvement, and not, for example, to wear, how do machine parts wear out?
Darwin argued that modifications are not inherited, since there is no and cannot exist a mechanism that would lead to a change in the DNA structure of germ cells in parallel and adequately to those changes that occur in organs and tissues (bones, muscles) during adaptive modifications. Experiments in no case have succeeded in proving the stable inheritance of traits acquired by their ancestors by the descendants postulated by Lamarck and his followers.
3. Examine microscope preparations of plant and animal cells under a microscope. In what
are the similarities and differences between these cells?
1. Metabolism and transformation of energy as a property of organisms. The role of enzymes and ATP in metabolism.
All living organisms on Earth are open systems capable of actively organizing the flow of energy and matter from the outside. Energy is necessary for the implementation of vital processes, but above all for the chemical synthesis of substances used to build and restore the structures of the cell and the body. Living things are able to use only two types of energy: light (energy of solar radiation) and chemical (energy of bonds of chemical compounds) - according to this feature, organisms are divided into two groups - phototrophs and chemotrophs.
The main source of structural molecules is carbon. Depending on the carbon source, living organisms are divided into two groups: autotrophs, using a non-organic carbon source (carbon dioxide), and heterotrophs, using organic carbon sources. The process of consuming energy and matter is called nutrition. Two methods of nutrition are known: naked - by capturing food particles inside the body and holophytic - without capture, by absorbing dissolved nutrients through the surface structures of the body. Nutrients that enter the body are involved in metabolic processes. Metabolism is a set of interrelated and balanced processes that include a variety of chemical transformations in the body. Synthesis reactions, carried out with the consumption of energy, form the basis of anabolism (plastic metabolism or assimilation). Cleavage reactions, accompanied by the release of energy, form the basis of catabolism (energy exchange or dissimilation).
1. The value of ATP in metabolism
The energy released during the breakdown of organic substances is not immediately used by the cell, but is stored in the form of high-energy compounds, usually in the form of adenosine triphosphate (ATP). By its chemical nature, ATP belongs to mononucleotides and consists of the nitrogenous base of adenine, the carbohydrate ribose, and three phosphoric acid residues.
The energy released during the hydrolysis of ATP is used by the cell to perform all kinds of work. Significant amounts of energy are spent on biological synthesis. ATP is a universal source of energy supply for the cell. The stock of ATP in the cell is limited and is replenished due to the process of phosphorylation, which occurs with different intensities during respiration, fermentation and photosynthesis. ATP is renewed extremely quickly (in humans, the lifespan of one ATP molecule is less than 1 minute).
2. Energy metabolism in the cell. ATP synthesis
ATP synthesis occurs in the cells of all organisms in the process of phosphorylation, i.e. addition of inorganic phosphate to ADP. The energy for phosphorylation of ADP is generated during energy metabolism. Energy metabolism, or dissimilation, is a combination of the decomposition of organic substances, accompanied by the release of energy. Depending on the habitat, dissimilation can proceed in two or three stages.
In most living organisms - aerobes living in an oxygen environment - in the course of dissimilation, three stages are carried out: preparatory, oxygen-free, oxygen. In anaerobes living in an environment devoid of oxygen, or in aerobes with a lack of oxygen, dissimilation proceeds only in the first two stages with the formation of intermediate organic compounds that are still rich in energy.
The first stage - preparatory - consists in the enzymatic cleavage of complex organic compounds into simpler ones (proteins into amino acids; polysaccharides into monosaccharides; nucleic acids into nucleotides). Intracellular cleavage of organic substances occurs under the action of hydrolytic enzymes of lysosomes. The energy released in this case is dissipated in the form of heat, and the resulting small organic molecules can undergo further decomposition and be used by the cell as a "building material" for the synthesis of its own organic compounds.
The second stage - incomplete oxidation - is carried out directly in the cytoplasm of the cell, does not require the presence of oxygen and consists in the further splitting of organic substrates. The main source of energy in the cell is glucose. Anoxic, incomplete breakdown of glucose is called glycolysis.
The third stage - complete oxidation - takes place with the obligatory participation of oxygen. As a result, the glucose molecule is broken down to inorganic carbon dioxide, and the released energy is partially spent on the synthesis of ATP.
3. Plastic exchange
Plastic metabolism, or assimilation, is a set of reactions that ensure the synthesis of complex organic compounds in the cell. Heterotrophic organisms build their own organic matter from organic food components. Heterotrophic assimilation is essentially reduced to the rearrangement of molecules.
Food organic matter (proteins, fats, carbohydrates) -> digestion -> Simple organic molecules (amino acids, fatty acids, monosugar) -> biological syntheses ->
Autotrophic organisms are capable of completely independently synthesizing organic substances from inorganic molecules consumed from the external environment. In the process of autotrophic assimilation, the reactions of photo- and chemosynthesis, ensuring the formation of simple organic compounds, precede the biological synthesis of molecules of macromolecules:
Inorganic substances (carbon dioxide, water) -> photosynthesis, chemosynthesis -> Simple organic molecules (amino acids, fatty acids, monosugar) ----- biological syntheses -> Macromolecules of the body (proteins, fats, carbohydrates)
4. Photosynthesis
Photosynthesis is the synthesis of organic compounds from inorganic ones, which comes from the energy of the cell. The leading role in the processes of photosynthesis is played by photosynthetic pigments, which have a unique property - to capture light and convert its energy into chemical energy. Photosynthetic pigments are a fairly large group of protein-like substances. The main and most important in terms of energy is the pigment chlorophyll a, which is found in all phototrophs, except for photosynthetic bacteria. Photosynthetic pigments are embedded in the inner plastid membrane in eukaryotes or in the invaginations of the cytoplasmic membrane in prokaryotes.
In the process of photosynthesis, in addition to monosaccharides (glucose, etc.), which are converted into starch and stored by the plant, monomers of other organic compounds are synthesized - amino acids, glycerol and fatty acids. Thus, thanks to photosynthesis, plant cells, or rather chlorophyll-containing cells, provide themselves and all life on Earth with the necessary organic substances and oxygen.
2. The doctrine of N.I. Vavilov on the centers of diversity and origin of cultivated plants,
his assessment.
3. Consider on herbarium specimens the modifications of various organs in plants (peas, barberry, acacia, hawthorn, wild rose). Determine which organs are homologous and which are similar. Explain the origin of these organs and their function.
1. Development of knowledge about the cell. The main provisions of the cell theory.
All living organisms are made up of cells. A cell is an elementary unit of the structure, functioning and development of living organisms. There are non-cellular life forms - viruses, but they show their properties only in the cells of living organisms. Cellular forms are divided into prokaryotes and eukaryotes.
The discovery of the cell belongs to the English scientist R. Hooke, who, looking through a thin section of the cork under a microscope, saw structures similar to a honeycomb, and called them cells. Later, the Dutch scientist Anthony van Leeuwenhoek studied unicellular organisms. The cell theory was formulated by the German scientists M. Schleiden and T. Schwann in 1839. The modern cell theory was substantially supplemented by R. Birzhev et al.
The main provisions of modern cell theory:
a cell is the basic unit of the structure, functioning and development of all living organisms, the smallest unit of living, capable of self-reproduction, self-regulation and self-renewal; cells of all unicellular and multicellular organisms are similar (homologous) in their structure, chemical composition, the main manifestations of vital activity and metabolism; cell multiplication occurs by dividing them, each new cell is formed as a result of the division of the original (mother) cell; in complex multicellular organisms, cells are specialized in their functions and form tissues; organs are composed of tissues, which are closely interconnected and subject to nervous and humoral regulation. These provisions prove the unity of the origin of all living organisms, the unity of the entire organic world. Thanks to the cell theory, it became clear that the cell is the most important component of all living organisms. The cell is the smallest unit of an organism, the border of its divisibility, endowed with life and all the basic characteristics of the organism. As an elementary living system, it underlies the structure and development of all living organisms. At the level of the cell, such properties of life as the ability to metabolize and energy, autoregulation, reproduction, growth and development, and irritability are manifested.
2. Biological progress and biological regression. The reasons for the extinction of species.
3. Determine the relationship in which the listed
organisms: algae and mushrooms in lichen, fox and hare, fox and wolf, liver
fluke and cow.
To what group of environmental factors do these relationships belong?
algae and fungi in lichen are symbiosis
fox and hare - a kind of relationship "predator-prey"
Fox and wolf - competition
These biotanical relationships are referred to as biotic factors.
1. Patterns of heredity established by G. Mendel.
Genetics is a science that studies the laws of heredity and variability of living organisms. Heredity is the property of all living organisms to transmit their characteristics and properties from generation to generation. Variability is the property of all living organisms to acquire new characteristics in the process of individual development. Elementary units of heredity - genes - are sections of the DNA of chromosomes. The patterns by which signs are passed from generation to generation were first discovered by the great Czech scientist Gregor Mendel (1822-1884). Gregor Mendel became a monk at the age of 25, after which he took a course in mathematics and natural sciences at the University of Vienna. Later, from 1868, he was the abbot of the Augustinian monastery in the Czech city of Brno and at the same time taught natural history and physics at the school. For many years, Mendel, as an amateur botanist, conducted experiments in the monastery garden and in 1865 published his work "Experiments on plant hybrids", in which he outlined the basic laws of heredity. Hybridological method. The basis of G. Mendel's remarkable work was the so-called hybridological method. The essence of this method lies in the crossing (hybridization) of organisms that differ from each other in some traits, and in the subsequent analysis of the inheritance of these traits in the offspring. The hybridological method is still at the heart of the research of all geneticists. During his experiments, Mendel adhered to several rules. First, working with garden peas, he used plants that belonged to different varieties to cross. So, for example, one variety always had yellow peas, while the other always had green peas. Since peas are a self-pollinated plant, these varieties do not mix under natural conditions. These varieties are called clean lines. Secondly, in order to obtain more material for the analysis of the laws of heredity, Mendel worked not with one, but with several parental pairs of peas. Thirdly, Mendel deliberately simplified the task, observing the inheritance of not all the traits of peas at once, but only one pair of them. For his experiments, he initially chose the color of pea seeds - peas. In cases where parental organisms differ in only one trait (for example, only in the color of the seeds or only in the shape of the seeds), the crossing is called monohybrid. Fourthly, having a mathematical education, Mendel used quantitative methods to process the data: he not only noticed what the color of pea seeds in the offspring was, but also accurately calculated how many such seeds appeared. It should be added that Mendel very well chose peas for his experiments. Peas are easy to grow, under the conditions of the Czech Republic, they multiply several times a year, pea varieties differ from each other in a number of well-visible signs, and, finally, in nature, peas are self-pollinating, but in an experiment this self-pollination is easy to prevent, and the experimenter can pollinate the plant with pollen from another plants, i.e. crosswise.
If we use the terms that appeared many years after Mendel's work, then we can say that the cells of pea plants of one variety contain two genes of only yellow color, and the genes of plants of another variety - two genes of only green color. Genes responsible for the development of one trait (for example, seed color) are called allelic genes. If an organism contains two identical allelic genes (for example, both genes for green seeds or, conversely, both genes for yellow seeds), then such organisms are called homozygous. If the allelic genes are different (that is, one of them determines the yellow, and the other - the green color of the seeds), then such organisms are called heterozygous.
Biotic - connections between living organisms in an ecosystem. The main type of biotic links is food links (food chains).
Links in the food chain:
Producers - plants and some bacteria that create organic matter from inorganic;
Consumers - animals, some plants and bacteria that feed on ready-made organic substances;
Destroyers - fungi and some bacteria that break down organic matter to inorganic.
3. Intraspecific relationships - biotic relationships between individuals of the same species. Examples: competition between males for the female, the struggle of individuals for leadership in the group, parental care for offspring, the protection of young animals and females by males.
5. Predation - direct food connections between organisms, in which some organisms are destroyed by other organisms. Examples: fox eating hares, tit eating caterpillars.
6. Competition is a type of relationship that arises between species with similar ecological needs due to food, territory, etc. Example: competition between elk and bison living in the same forest for food. The negative impact of competition on both competing species (for example, a decrease in the number of elk and bison due to a lack of food).
8. Symbiosis is a type of interspecies relationship in which both organisms receive mutual benefit. Examples of symbiosis: hermit crab and anemones, root plants and bacteria, cap mushrooms and trees, lichens (fungus and algae symbiosis).
3. Prepare a micropreparation of onion skin and examine it under a microscope.
Sketch the cell and label the visible parts and organelles of the cell.
1. Phenotypic (non-hereditary) variability.
Modification (phenotypic) variability is associated with the reaction of the same genotype to a change in external conditions in which organisms develop and which create differences in the forms of its manifestation. The same genotype appears in different phenotypes. Genotype and phenotype are the most important concepts of genetics, they were proposed by Wilhelm Ludwig Johansen (1857-1927) in 1909 (Danish biologist, professor at the Institute of Plant Physiology at Copenhagen University, member of the Swedish Academy of Sciences). The genotype (from the Greek - birth, imprint, image) is the totality of all genes of an organism, its hereditary material basis.
Phenotype (from the Greek - phenomenon, imprint, image) - a set of all the characteristics and properties of an organism, formed on the basis of a genotype. Any phenotype of an organism is the result of the realization of a genotype under specific environmental conditions. The differences between phenotypes developing on the basis of the same genotype show modification variability. In the specific forms of certain phenotypes, the interaction between the genotype and the external conditions in which the organism develops is expressed. External conditions have a huge impact on all the signs and properties of the developing organism.
Example: White cabbage does not form a head in hot climates. Horse and cow breeds brought into the mountains become stunted
Hereditary variability. Hereditary variability includes such changes in the characteristics of an organism, which are determined by the genotype and persist in a number of generations. Sometimes these are large, clearly visible changes. For example, short legs in sheep, lack of plumage in chickens, lack of pigment (albinism) or polydactyly (multiple fingers, extra toes on the hand or foot) Genotypic variability is variability resulting from new genetic combinations as a result.
Or sexual reproduction, crossing over (the phenomenon of exchange of regions of homologous chromosomes during conjugation1 during meiosis2). and other rearrangements at the chromosomal level;
Or under the influence of mutations (mutational variability).
Genotypic variability is subdivided into mutational and combinative. They lead to an increase in intraspecific diversity in nature.
Mutational variability is associated with the process of mutation formation. Mutations are sudden, abrupt, persistent changes in the structure of the genotype. Organisms that have mutated are called mutants. The mutational theory was created by Hugo de Vries (Hugo de Vries, Netherlands. Hugo de Vries, 1848-1935 - Dutch botanist, geneticist) in 1901-1903. Modern genetics is based on its main principles: mutations, discrete changes in heredity, are spontaneous in nature, mutations are inherited, they are quite rare and can be of various types.
Classification of mutations.
1. By the way of origin. Distinguish between spontaneous and induced mutations Spontaneous occur in nature extremely rarely with a frequency of 1-100 per million copies of a given gene. At the present time, it is obvious that the spontaneous mutational process depends on both internal and external factors, which are called mutational pressure of the environment.
Induced mutations occur when a person is exposed to mutagens - factors that cause mutations. Mutagens are of three types:
* Physical (radiation, electromagnetic radiation, pressure, temperature, etc.).
* Chemical (cytostatics, alcohols, phenols, etc.).
* Biological (bacteria and viruses).
2. In relation to the primordial path. There are somatic and generative mutations. Generative mutations occur in reproductive tissues and are therefore not always detected. In order for a generative mutation to emerge, it is necessary for the mutant gamete to participate in fertilization.
3. By adaptive value. There are positive, negative and neutral mutations. This classification is associated with the assessment of the viability of the resulting mutant.
4. By changing the genotype. Mutations are genetic, chromosomal, and genomic.
5. By localization in the cell. Mutations are divided into nuclear and cytoplasmic. Plasma mutations result from mutations in plasmagens found in mitochondria. It is believed that they lead to male infertility. Moreover, such mutations are mainly inherited in the female line.
Combinative variability arose with the advent of sexual reproduction, it is associated with various options for the recombination of parental inclinations and is the source of an infinite variety of combined traits.
Mutagenic factors.
Mutagen is a factor that causes mutation.
Any mutations can occur spontaneously or be induced. Spontaneous mutations appear under the influence of unknown natural factors and lead to errors in DNA replication. Induced mutations arise under the influence of special targeted factors that increase the mutational process. Factors of physical, chemical and biological nature have a mutagenic effect.
1. Among physical mutagens, the most powerful mutant effect is exerted by ionizing radiation - X-rays, α-, β-, γ-rays.
2. Chemical mutagens must have the following properties:
High penetrating power;
The property to change the colloidal state of chromosomes;
A certain effect on the state of a chromosome or gene. Chemicals that cause mutations include organic and inorganic substances such as acids, alkalis, peroxides, metal salts, formaldehyde, pesticides, defoliants, herbicides, colchicine, etc.
3. In addition to mutagens of physical and chemical nature, there are biological factors of mutagenesis in the environment. Smallpox, measles, chickenpox, mumps, hepatitis, rubella, etc. viruses can cause chromosome breaks.
2. Artificial communities - agroecosystems, the role of man in them.
LIFE IN AGRO - AND URBOECOSYSTEMS. LIFE IN EXTREME CONDITIONS. Life in agroecosystems is characterized by pollution of the environment with pesticides that are used in agriculture. So, for the destruction of economically harmful insects, insecticides are used; fungal diseases of plants - fungicides; weeds - herbicides. At the same time, there is an impact on all levels of life in agroecosystems - from biogeocenosis as a whole to populations and individual individuals. In such cases, scientists point to the possibility of responses from nature and its components to humans and their environment in agroecosystems. Moreover, agroecosystems are, in fact, artificial with the creation of an ecological absurdity by man: an agrocenosis consists of one, less often - two types of cultivated plants, and the ideal food chain for it consists of only two links: "plant - human" or "plant - domestic animals" ... In nature, such a system is impossible due to its instability. In the constant struggle of a person with weeds and pests of cultivated plants, the effect of "ecological boomerang" often arises. This is a set of negative, especially dangerous phenomena that arise in the environment as a result of improper economic activities of a person, which ultimately turn out to be harmful to him. In particular, when using pesticides against agricultural pests, beneficial pollinating insects (bees, wasps, bumblebees) also die. The economic and social advantages of urban forms of settlement are undeniable. However, the growth of the urban population with the creation of urban ecosystems in recent decades has turned out to be so rapid, and the concentration and intensification of production and non-production activities is so high that the environment of many cities in the world is no longer able to satisfy many biological and social requirements of modern man. Excessive population density in cities gives rise to such problems as environmental pollution, noise, lack of housing, schools, hospitals, transport, green spaces, random traffic, unemployment, crime, mass diseases of various types, etc. Living in extreme conditions requires from a person of large material and energy costs. This is clearly seen in the example of the northern cities of Russia, in the Arctic. To maintain normal living conditions in these cities, huge fuel and energy resources are expended, while environmental pollution, and above all the atmosphere, from burning fuel during a long cold period occurs. Long-term residence of a person in extreme conditions negatively affects health. Life expectancy among northerners is lower than among inhabitants of temperate latitudes. In Soviet times, people who worked and lived in extreme conditions were given wage increments, while the length of service went 1 to 2 or 1 to 1.5 years, that is, increased by 1.5-2 times.
3. From the available organisms, make up the food chain: golden eagle, grasshopper, shrew,
herbaceous plants. Determine which functional group the golden eagle belongs to in
compiled food chain. Explain the answer.
1. The reasons for the stability of ecosystems, their change. Anthropogenic changes in ecosystems.
the ability of an ecosystem to return to its original state after a temporary external influence is the recoverability of the system (elastic stability, elasticity).
The first two concepts are interpreted as adaptive resistance, the third - as regenerative. If a particular function of the ecosystem under the influence of a disturbance deviates from the “norm”, the degree of this deviation shows the relative stability of the system, and the time required to restore the “norm” - its relative elasticity. There are several different mechanisms for ensuring environmental sustainability:
1) constancy is achieved due to the action of negative feedbacks that keep the ecosystem in a stable state (homeostasis). In this case, the principle of Le Chatelier-Brown operates: when an external influence takes the system out of a state of stable equilibrium, the equilibrium shifts in the direction in which the effect of the external influence is weakened;
2) environmental sustainability is ensured by the redundancy of functional elements. For example, if a community includes several populations of autotrophic organisms, each of which has its own temperature optimum for photosynthesis, then
the photosynthesis of the community as a whole will change slightly with temperature fluctuations under certain conditions. In this case, the sustainability of an ecosystem is directly related to its species diversity;
3) adaptation - restructuring of the structural elements of the system without significant changes in its functions. Reorganization can also be irreversible, for example, in the process of evolution.
Populations or species generally develop in ecosystems surrounded by other species. While studying the paleobotany of the “bygone biospheres,” Vernadsky showed that in the course of the evolution of life on Earth, the structure of biogeocenoses changed and became more complex (first, chemotrophs, then phototrophs, etc.). With the appearance of the first phototrophs (algae), the process of formation of primary ecosystems ended, and the circuit of the cycle of substances was closed, but there were excess biogenic products → heterotrophs appeared, etc., but these ecosystems were unstable, quickly appeared and disintegrated (i.e. microorganisms quickly multiplied - a rapid change of generations) → evolution accelerated. The emergence of multicellular organisms was accompanied by an increase in the stability of ecosystems. When plants emerged on land → many new habitats → rapid evolution → a huge amount of organic matter was not consumed and was removed from the biotic cycle in the form of coal, oil, etc. that have come down to us. until a sufficient number of consumers appeared. The middle of the Cretaceous - herbaceous plants and annuals appeared → different acceleration of nutrient circles, because there were many animals and rodents. An important success was the formation of the biotic cycle - the creation of such living environments in which the same portion of a substance can be used repeatedly. This became possible when the triad arose: producer → consumer → reducer. The further direction of the evolution of ecosystems led to a decrease in the consumption of substances from biotic cycles and an intensification of the migration of chemical elements (in animals, this is the appearance of warm-bloodedness, since mammals spend only 1% of the substances they consume to create their biomass; in plants, this is the appearance of annuals). In the process of life development, ecosystems become more complex. The main integrating factor in the life of a biogeocenosis is food relationships. A certain complex structure of biogeocenosis is a necessary prerequisite for maintaining its stability. The most fragile and unstable ecosystems with the fewest components (tundra). The most stable ecosystems are tropical forests, where flows of matter and energy are repeatedly duplicated (there are a lot of species and a small number of each) - they can withstand the loss of a percentage of their constituent components without prejudice to their functioning. All ecosystems are a real environment for interspecific relationships, → constant interactions of all components of the biogeocenosis are the cause of changes in biogeocenosis and other ecosystems → transformation of the biosphere. Change of biogeocenoses - succession. The climax community is stable in balance with the environment.
General features of changes in biogeocenoses:
1) all biotic systems are dynamic and mobile, responsive to the influence of the external environment;
2) in the process of ecosystem development, lengthening of food chains is observed, an increase in the number of trophic levels → differentiation of matter and energy flows occurs (narrow food specialization of species);
3) as a result of lengthening food chains, the retention time of matter and energy increases (a circle of long-lived organisms appears).
2. Reproduction, its role in nature. Sexual and asexual reproduction of organisms.
Reproduction - the ability to reproduce their own kind, inherent in all organisms and ensuring the preservation of a biological species, and therefore
life on Earth. Various forms of reproduction are known in nature. Asexual reproduction in a broad sense includes division, sporulation, vegetative reproduction, including budding and fragmentation. Specific forms of sexual reproduction are conjugation (in some algae, ciliates, bacteria), in which there is a temporary connection of two unicellular individuals, accompanied by the exchange of some parts of the nuclear apparatus, and parthenogenesis. The latter phenomenon (literally meaning virgin reproduction - Greek parthenos - virgin and genesis - birth) is unisexual reproduction, in which the development of the embryo from the egg occurs without fertilization. Sexual reproduction is typical for most inhabitants of the Earth. The specific mechanisms of the role of dioeciousness in the evolutionary process, shedding light on a number of problems of clinical sexopathology, are revealed in a series of works by the Soviet researcher V.A.Geodakyan. In most sexually reproducing organisms, sex cells (gametes) differentiate from other cells in the body that have a standard set of chromosomes (autosomes, or euchromosomes). In multicellular animals, both female gametes (eggs) and male (sperm) are produced in special gonads (gonads), subdivided into female - ovaries and male - testes, and the meeting of gametes and their fusion (fertilization) is facilitated by the presence of special genital organs. Cytogenetic studies have established that in higher organisms, all somatic cells of both sexes have the same double set of autosomes (2A) and different sex chromosomes. In this case, one sex gives only one type of gametes (for example, in the human ovaries, only sex chromosomes of type X are normally formed), and the other sex gives two types of gametes (for example, in the testes of a person - sex chromosomes of types X and Y). Thus, one of the sexes (in humans - male), formed from two different gametes, has a hybrid genetic constitution (XY) and is therefore called heterogametic. The opposite sex, defined by a set of two gametes of the same type (XX), has a homogeneous genetic constitution and is called homogametic. In most species, including all mammals, the male sex is heterogametic. However, in some species, in particular in birds and butterflies, the female sex is heterogametic. Thus, in humans and other mammals, the sex of the embryo is determined singamo, that is, during the act of fertilization. In organisms with male heterogamety, fertilization of an egg by a sperm carrying a Y chromosome leads to the development of a male embryo, and fertilization by a sperm carrying an X chromosome leads to the development of a female embryo. This implies that spermatozoa carrying X- and Y-chromosomes are formed in the gonads in equal quantities and, therefore, the appearance of that ilm of the other sex has an equal degree of statistical probability, entirely depending on the game of chance.
3. At great depths in the ocean, there are practically no plant organisms. However, various animals live here: sponges, hydroid polyps, horny corals, bivalve molluscs, annelids, crabs, bottom fish, etc. How can you explain the absence of plants and what serves as food for the animals living here?
1. Trophic levels of organisms in the ecosystem, their role.
2. Cell division is the basis for the growth, development and reproduction of organisms. Mitosis.
Cell division is the basis for the reproduction and growth of organisms Cell division is the process underlying the reproduction and individual development of all living organisms. The nucleus plays the main role in cell division. On stained cell preparations, the content of the nucleus at rest is represented by chromatin, which is distinguishable in the form of thin strands (fibrils), small granules and lumps. The basis of chromatin is formed by nucleoproteins - long threadlike molecules
DNA (chromatids) linked to specific proteins, histones. In the process of nuclear fission, nucleoproteins spiralize, shorten and become visible under a light microscope in the form of compact rod-shaped chromosomes. Each chromosome has a primary constriction (a thinned non-helical region) - a centromere that divides the chromosome into two arms. Mitosis is an indirect cell division that is widespread in nature. Thanks to mitosis, an even distribution of genetic material between the two daughter cells is ensured. Mitosis has four successive phases. The period of a cell's life between two mi-gothic divisions is called interphase. It is ten times longer than mitosis. In this phase, the synthesis of ATP molecules and proteins, DNA doubling, doubling of some organelles of the cell takes place. In prophase, DNA spiralization begins. Thickened and shortened DNA strands consist of two chromatids. By the end of prophase, the nuclear membrane and nucleoli disappear. The centrioles of the cell center diverge to the poles, and a division spindle is formed. In metaphase, the final spiralization of chromosomes occurs, their centromeres are located along the equator, attaching to the filaments of the fission spindle. In anaphase, centromeres divide, sister chromatids are separated
3. Solve the problem. In mice, long ears are the dominant feature, and short ears are
recessive. A male with long ears was crossed with a female with short ears. V
the first generation all offspring turned out with long ears. Identify genotypes
parents and offspring.
According to 1 Mendel's law, all offspring will be long-eared
The answer is 100% long-eared heterozygotes (Aa).
1. Fertilization, its meaning. Features of fertilization in animals.
Fertilization in plants. The importance of the aquatic environment for the fertilization process in mosses and ferns. The fertilization process in gymnosperms is in female cones, and in angiosperms - in a flower. Fertilization in animals. External fertilization is one of the reasons for the death of a significant part of germ cells and zygotes. Internal fertilization in arthropods, reptiles, birds and mammals is the reason for the most likely formation of a zygote, protection of the embryo from adverse environmental conditions (predators, fluctuations
2. Levels of organization of wildlife.
Molecular. Any living system, no matter how complex it is organized, consists of biological macromolecules: nucleic acids, proteins, polysaccharides, and other important organic substances. From this level, various vital processes of the organism begin: metabolism and transformation of energy, transmission of hereditary information, etc. Cellular. A cell is a structural and functional unit, as well as a unit of development for all living organisms living on Earth. At the cellular level, the transmission of information and the transformation of substances and energy are coupled.
Organizational. The elementary unit of the organismic level is an individual, which is considered in development - from the moment of inception to the end of existence - as a living system. At this level, organ systems arise that are specialized to perform various functions. A set of organisms of the same species, united by a common habitat, in which a population is created - a supraorganismic system. In this system, elementary evolutionary transformations are carried out - the process of microevolgo. Biogeocenosis - a set of organisms of different species "and varying complexity of organization with factors of their habitat. In the process of joint historical development of organisms of different systematic groups, dynamic, stable communities are formed. Biosphere. Biosphere is the totality of all biogeocenoses, a system that encompasses all the phenomena of life on our planet. At this level, there is a circulation of substances and a transformation of energy associated with the vital activity of all living organisms.
3. Distribute the listed oak forest plants in tiers: maple, oak, hazel, lily of the valley,
linden, bracken fern, viburnum, apple tree, two-leaved mine. What does it matter
layered arrangement of plants in an ecosystem?
1. The main aromorphoses in the evolution of plants.
Aromorphoses are a major evolutionary change. It provides an increase in the level of organization of organisms, advantages in the struggle for existence, the possibility of mastering new habitats.
1. The emergence of chloroplasts with chlorophyll in cells, photosynthesis is an important aromorphosis in the evolution of the organic world, which provided all living things with food and energy, oxygen. The appearance from unicellular multicellular algae is an aromorphosis that contributes to an increase in the size of organisms.
2. Four-chambered heart, complete separation of arterial and venous blood, warm-bloodedness, a high degree of development of the cerebral cortex, intrauterine development of the embryo, the presence of mammary glands and feeding the baby with milk, the presence of a diaphragm
2. The biosphere is a global ecosystem. The teachings of V.I. Vernadsky about the biosphere.
(notebook)
3. Solve the problem. In peas, normal growth is inherited as a dominant trait.
A normal-growing pea plant is crossed with a dwarf one. In the offspring it happened
splitting traits: half of the plants were of normal growth, and half were
dwarf. Determine the genotypes of the parents and offspring.
A - allele of the gene of normal growth,
a - allele of the dwarf growth gene. This means that the dwarf plant has the genotype aa, well, and
since offspring had both normal and dwarf growth, therefore the parent with normal growth was heterozygous Aa. See further.
F1 2Aa (50% normal growth) and 2aa (50% dwarf growth)
ANSWER: genotypes of parents (see P): Aa and aa, genotypes of offspring (see F1): Aa and aa
1. The main aromorphoses in the evolution of vertebrates.
Aromorphosis is a major evolutionary change. It provides an increase in the level of organization of organisms, advantages in the struggle for existence, the possibility of mastering new habitats. The factors causing aromorphoses are hereditary variability, the struggle for existence and natural selection. The main aromorphoses in the evolution of multicellular animals:
1) the emergence of multicellular animals from unicellular ones, cell differentiation and tissue formation;
2) the formation of bilateral symmetry in animals, the front and rear parts of the body, the abdominal and dorsal sides of the body in connection with the separation of functions in the body (orientation in space - the front part, protective - the dorsal side, movement - the abdominal side);
3) the emergence of cranial fish, similar to the modern lancelet, armored fish with bony jaws, allowing active hunting and coping with prey:
4) the appearance of the lungs and the appearance of pulmonary respiration along with the branchial;
5) the formation of the skeleton of fins with muscles similar to the five-fingered limb of terrestrial vertebrates, which allowed the animals not only to swim, but also to crawl along the bottom, to move on land;
6) complication of the circulatory system from a two-chambered heart, one circle of blood circulation in fish to a four-chamber heart, two circles of blood circulation in birds and mammals. Development of the nervous system: cobweb in intestinal cavity, abdominal chain in annelids, tubular nervous system, significant development of the cerebral hemispheres and cerebral cortex in birds, humans and other mammals. Complication of the respiratory system (gills in fish, lungs in terrestrial vertebrates, the appearance in humans and other mammals in the lungs of many cells entwined with a network of capillaries). The emergence of chloroplasts with chlorophyll in cells, photosynthesis is an important aromorphosis of the evolution of the organic world, which provided all living things with food and energy, oxygen. Further complication of plants in the process of evolution: the emergence of roots, leaves, a developed stem, tissues that allowed them to master the land (ferns, horsetails, lyes). Aromorphoses that contribute to the complication of plants in the process of evolution: the emergence of a seed, flower and fruit (the transition of seed plants from reproduction by spores to reproduction by seeds). The spore is one specialized cell, the seed is the rudiment of a new plant with a supply of nutrients. The advantages of plant propagation by seeds are the reduction of the dependence of the reproduction process on the environment and an increase in survival.
2. The role of living organisms in the biosphere. Human influence on the biosphere.
All living organisms that inhabit our planet do not exist on their own, they depend on the environment and experience its effects on themselves. Wildlife is a complex, hierarchical system. There are several levels of organization of life on our planet, and the highest of them is the biosphere.
From modern positions, the biosphere is considered as the largest ecosystem on the planet that supports the global circulation of substances. The stability of the biosphere is based on a high diversity of living organisms, individual groups of which perform different functions in maintaining the general flow of matter and the distribution of energy. However, the stability of the biosphere has certain limits, and the violation of its regulatory capabilities is fraught with serious consequences. Considering that complex systems of feedbacks and dependencies operate in the biosphere, then, accordingly, as the pressure on the environment increases, the environment, in turn, responds with an increase in the counter pressure. For example, man has always used the environment mainly as a source of resources, but for a very long time his activities did not have a noticeable effect on the biosphere. Only at the end of the last century, changes in the biosphere under the influence of economic activity attracted the attention of scientists. These changes were growing and are currently hitting human civilization. We had to admit that even vital resources for the human economy are sometimes even more important for maintaining ecological balance in the biosphere and, ultimately, for optimal natural conditions for the existence and development of mankind, for present and future generations. That is why it is relevant today to study the problem of human interaction with the environment. It is the organic "cooperation" of these two elements that will contribute to the long and stable existence of the biosphere. The purpose of this work is as follows: to show that a person is not a self-sufficient living being living separately according to his own laws, he coexists inside nature, is a part of it and obeys its laws. For this it is necessary to determine the place of humanity in the structure of the biosphere; how the human impact on the biosphere is carried out and what are the results of this impact; how the biosphere reacts to any changes in the processes taking place in it. Only after considering these issues can we conclude that a person in all its manifestations is a part of the biosphere and is its definite function in a definite space-time.
3. Consider several types of fruits from different plants (maple, dandelion, burdock,
mountain ash, peas, etc.). What are the types of fruits and signs of adaptability to
the spread of seeds in each plant.
1. The main features of the living.
Distinctive features of living organisms.
REDUCING BIOLOGICAL DIVERSITY.
With the development of civilization, its influence on nature increases. More and more territory of the city and agricultural land, there are fewer corners on our planet where animals could exist in natural conditions. As the population grows and economic activity expands, untouched areas of nature are reduced. The main breeding areas, migration routes, hunting zones, feeding areas of herbivores disappear under artificial turf, are flooded with water, "fed" to livestock or plowed up. Forest areas are stripped by loggers, turned into pastures, used for sowing or planted with trees alien to the area. The problem of reducing biological diversity due to the destruction of natural areas of nature is typical for all natural areas of the earth.
In the last decade, the anthropogenic impact on the natural landscapes of the tundra zone has greatly increased. Anthropogenic transformation of typical tundra of the Yamal Peninsula. At the site of the complete destruction of moss-lichen tundras, thermokarst and erosion processes begin to actively develop (the growth of ravines in the vicinity of settlements reaches 15-30 m per year). An alarming situation has developed in the Yashkul region of Kalmykia, where the main herd of the European saiga population is concentrated. Once these ungulates, contemporaries of mammoths, grazed in vast open spaces from the Tien Shan to the Carpathians. Now there is a sharp decline in the number of this species, ideally adapted to the conditions of dry steppes. Animals, especially young animals, drown in thousands in the waters of irrigation canals, cutting the original migratory routes of saigas. Poachers shoot hundreds of them per night. But the main reason for the decline in the number of saigas is the progressive process of anthropogenic desertification in the Caspian steppes, which is rapidly reducing the areas suitable for habitation of these animals.
As a result of thoughtless industrial and agricultural land development, environmental pollution in the United States is destroyed or sent to the natural habitats of wild waterfowl, rare animals. Ducks, geese, swans and other species of birds flying there from Canada and Alaska die in the millions. In the world's oceans, due to predatory fishing and the ever-increasing pollution and destruction of the environment, 25 species of the most valuable commercial fish have either been almost completely destroyed or their numbers have sharply declined. Up to 250 thousand individuals of various species of dolphins are annually destroyed. Dugongs and sea turtles die, and about a million seabirds die in fishing nets every year.
At present, almost all the basins of the surface runoff of the European and Asian part of Russia have been transformed by hydroelectric construction. This significantly disrupted the reproduction of fish stocks in inland water bodies, primarily valuable anadromous and semi-anadromous fish, such as sturgeon, salmon, Caspian herring, roach, vimbets. Losses from fluctuations in the water level in connection with the operation of hydroelectric facilities are equal to the value of the annual catch in reservoirs (50-70 thousand tons) or exceed it. In irrigation systems, waterworks and industrial water intakes, more juveniles of commercial fish perish than are produced by all fish factories in Russia. Thus, as a result of anthropogenic destruction of the habitat, there is a sharp decline in the number and even the disappearance of many species of living beings. In the last three centuries alone, 120 animal species have disappeared on our planet. According to experts, in the next 30 years, the same fate may befall about 100 more species, which will negatively affect people's lives.
Scientific ecological research in the field of studying the protection of the gene pool of wild animals and plants makes it possible to ensure the safety of many valuable and rare animals and plants.
ENVIRONMENTAL POLLUTION.
The problem of a healthy environment has become as vital as the problem of providing people with food or energy. It is well known that human health depends on the state of the environment. Even hereditary diseases are ultimately, from a historical point of view, the result of interactions between an unfavorable environment and many previous generations of people.
At present, as a result of human economic activity, environmental pollution has taken on a gigantic scale and can have a number of undesirable consequences: damage to flora and fauna (decrease in the productivity of forests and cultivated plants, extinction of animals); violation of the stability of natural biocenoses; damage to property (corrosion of metals, destruction of architectural structures); harm to human health. Many of the pollutants (pesticides, polychlorinated biphenyls, plastics) decompose extremely slowly in natural conditions, and taxic compounds (mercury, lead) are not neutralized at all. Especially a lot of pollutants enter the environment as a result of energy production from burning fossil fuels. Man, releasing solar energy in this way, accelerates the circulation of substances and energy in nature. Industrial waste and pollutants (carbon monoxide, nitrogen oxides, hydrocarbons, particulate matter, etc.) of the atmosphere disrupt the natural carbon cycle, contributing to a number of negative consequences (greenhouse effect, photochemical smog, etc.).
Various industries emit a large amount of pollutants into the atmosphere, in particular, metallurgical enterprises of the world annually emit more than 150 thousand tons of copper, 120 thousand tons of zinc, 90 thousand tons of nickel, cobalt, mercury, etc.
Agriculture is also a significant environmental pollutant. Thus, there are more than 1,500 pesticides in the world alone (in Russia, only 150-160 are used so far). A particular danger is caused by the use of organophosphate pesticides, which are potent poisonous substances that lead to the mass death of birds (starlings, blackbirds, doves, etc.).
Environmentalists are sounding the alarm about the catastrophic decline in biodiversity on our planet, associated with the activities of modern man, who for the most part, living in the city, practically does not encounter nature, has no idea about its diversity and can only see on TV. This makes him feel like biodiversity is not part of everyday life, but it is not.
What is biodiversity?
Scientists understand the term biodiversity to mean the diversity of life on Earth - plants, animals, insects, fungi, bacteria and the ecosystems that they form. In this concept, there is also a relationship that is present between them. Biodiversity can flow:
- at the level of genes, determines the variability of individuals of a certain species;
- at the species level, reflects the diversity of species (plants, animals, fungi, microorganisms);
- diversity this includes differences between them and different ecological processes).
It should be borne in mind that all the above types of diversity are interrelated. Many ecosystems and different landscapes create conditions for the emergence of new species, genetic diversity makes it possible to change within one species. The decline in biodiversity indicates certain violations of these processes.
At present, ecologists are sounding the alarm due to the fact that living conditions, ecological processes are violated by man, man creates new species of plants and animals at the genetic level. How this will affect future life on Earth is unknown. After all, in nature, everything is interconnected. This is evidenced by the so-called "butterfly effect". The science fiction writer Ray Bradbury told the world about it in his story "And Thunder Rocked" back in the middle of the last century.
Impossibility of life without biodiversity
The most valuable and important thing on earth is biological diversity. Whether we know about it or not, our whole life depends on the biological wealth of the earth, since animals and vegetation give it to us. Thanks to plants, we get a sufficient amount of oxygen, and materials based on them give us not only food, but also wood, paper, fabrics.
In our technogenic age, a huge amount of energy is needed, obtained by burning fuel, which is produced from oil formed as a result of the decomposition of the remains of many organisms and plants. Human life is impossible without biological diversity.
Coming to the store, we buy food packed in bags, thinking little about where it comes from. The life of the majority of the population lives in an artificial environment, which is made up of asphalt, concrete, metal and artificial materials, but this does not mean that the consequences of reducing biodiversity will bypass humanity.
Life on Earth and its diversity
The history of the planet Earth suggests that at different times it was inhabited by many living organisms, most of which, as a result of evolution, died out and gave way to new species. This was facilitated by conditions and reasons, but even during periods of natural stagnation, there was no reduction in biodiversity, diversity increased.
Nature is arranged in such a way that everything in it interacts. No species of living organisms can live and develop in a closed environment. This has been shown by numerous experiments on the creation of isolated biosystems that have suffered a complete collapse.
Modern scientists have described and studied 1.4 million species of living organisms, but according to calculations, there are from 5 to 30 million species on Earth that live and develop depending on conditions. This happens naturally. Living organisms have populated the entire planet. They live in water, air, land. They can be found in the desert and in the North and South belts. Nature provides everything you need to continue life on Earth.
With the help of living organisms, the nitrogen and carbon cycle takes place, which, in turn, supports the renewal and processing of natural resources. The environment favorable for life, created by the Earth's atmosphere, is also regulated by living organisms.
What contributes to the reduction of biodiversity?
First of all, the reduction of forest areas. As mentioned above, plants play a very important role in the life of the planet. The taiga and the jungle are called the lungs of the planet, thanks to which it receives a sufficient amount of oxygen. In addition, more than half of the species of living organisms exist precisely in the jungle, which occupies only 6% of the earth's surface. They are called the genetic fund accumulated over 100 million years of evolution on Earth. Its loss will be irreparable and could lead the planet to a complete ecological disaster.
The reasons for the decline in biodiversity are human activities transforming the planet in order to meet their, not always reasonably increased, needs. Uncontrolled felling of taiga and jungle leads to the disappearance of many species of life, even unexplored and not described by man, to the disruption of ecosystems and water balance.
This is facilitated by deforestation and burning of forests, harvesting of various types of plants and fisheries carried out in predatory proportions, the use of pesticides, drainage of swamps, the death of coral reefs and cutting of mangroves, an increase in the number of agricultural land and the area of settlements.
It is clear that the development of technology, technical progress cannot be stopped. But it is necessary to take measures to solve environmental problems of biodiversity loss.
International Convention on Biological Diversity
To this end, the "Convention on Biological Diversity" was adopted, which was signed by 181 countries, whose governments committed themselves to preserving it in their countries, pledged to act jointly with other states and share the benefits of the use of genetic resources.
But this has not prevented the decline in biodiversity on the planet. The ecological situation on Earth is becoming more threatening than ever. But there is hope that the common sense that God has given to man will prevail.
Evolution is the engine of life
The engine of life forward is evolution, as a result of which some species die out and new ones appear. All modern living things have replaced extinct ones, and, as scientists have calculated, out of the whole variety of species that existed on Earth, their current number is only 1% of their total number.
The extinction of species is a natural moment of evolution, but the current rate of decline in biodiversity on the planet is taking on alarming proportions, natural self-regulation is disrupted, and this has become one of the most important environmental problems of mankind.
The role of the species in the biosphere
Humanity's knowledge of the role played by representatives of a particular species in the biosphere is negligible. But scientists know for certain that each species has a certain meaning in nature. The disappearance of one species and the inability to replace it with a new one can lead to a chain reaction that will lead to the extinction of humans.
Necessary actions
The first step for humanity is to try to preserve the rainforests. Thus, leaving the opportunity to save some species of living things and plants from extinction. Preserving the jungle will stabilize the climate.
The jungle is a direct source of the richest genetic material, a treasury of various types of living beings. In addition, it is a source of plants, on the basis of which a person creates unique medicines. By moisturizing the atmosphere, rainforests prevent global climate change.
Biological diversity (BR) is the totality of all life forms that inhabit our planet. This is what makes the Earth different from other planets in the solar system. BR is the wealth and diversity of life and its processes, including the diversity of living organisms and their genetic differences, as well as the diversity of their places of existence. BR is divided into three hierarchical categories: diversity among representatives of the same species (genetic diversity), between different species and between ecosystems. Research of global BR problems at the gene level is a matter of the future.
The most authoritative assessment of species diversity was carried out by UNEP in 1995. According to this estimate, the most probable number of species is 13-14 million, of which only 1.75 million are described, or less than 13%. The highest hierarchical level of biological diversity is ecosystem, or landscape. At this level, the patterns of biological diversity are determined primarily by zonal landscape conditions, then by local features of natural conditions (relief, soil, climate), as well as by the history of the development of these territories. The greatest species diversity is (in descending order): humid equatorial forests, coral reefs, dry tropical forests, humid temperate forests, oceanic islands, landscapes of the Mediterranean climate, treeless (savanna, steppe) landscapes.
In the past two decades, biological diversity has begun to attract the attention of not only biologists, but also economists, politicians, and the public in connection with the obvious threat of anthropogenic degradation of biodiversity, far exceeding normal, natural degradation.
According to UNEP's Global Biodiversity Assessment (1995), more than 30,000 animal and plant species are at risk of destruction. Over the past 400 years, 484 animal species and 654 plant species have disappeared.
Reasons for the current accelerated decline in biological diversity-
1) rapid population growth and economic development, making huge changes in the living conditions of all organisms and ecological systems of the Earth;
2) increased migration of people, growth of international trade and tourism;
3) increasing pollution of natural waters, soil and air;
4) insufficient attention to the long-term consequences of actions that destroy the conditions for the existence of living organisms, exploiting natural resources and introducing non-native species;
5) impossibility in a market economy to assess the true value of biological diversity and its losses.
Over the past 400 years, the main direct causes of the extinction of animal species have been:
1) the introduction of new species, accompanied by the displacement or extermination of local species (39% of all lost animal species);
2) destruction of living conditions, direct withdrawal of territories inhabited by animals, and their degradation, fragmentation, increased marginal effect (36% of all lost species);
3) uncontrolled hunting (23%);
4) Other reasons (2%).
The main reasons for the need to preserve genetic diversity.
All species (no matter how harmful or unpleasant they may be) have a right to exist. This provision is recorded in the "World Charter for Nature" adopted by the UN General Assembly. Enjoyment of nature, its beauty and diversity is of the highest value, not expressed in quantitative terms. Diversity is the basis for the evolution of life forms. Declining species and genetic diversity undermines the further improvement of life on Earth.
The economic feasibility of biodiversity conservation is due to the use of wild biota to meet the various needs of society in industry, agriculture, recreation, science and education: for the breeding of domestic plants and animals, the genetic reservoir necessary to renew and maintain the resistance of varieties, the manufacture of medicines, as well as for providing the population with food, fuel, energy, timber, etc.
There are many ways to protect biological diversity. At the species level, there are two main strategic directions: in-situ and out-of-habitat. Protecting biodiversity at the species level is an expensive and laborious path, possible only for a select few species, but unattainable for protecting all the richness of life on Earth. The main thrust of the strategy should be at the ecosystem level, so that the systematic management of ecosystems ensures the protection of biological diversity at all three hierarchical levels.
The most effective and relatively economical way to protect biological diversity at the ecosystem level is protected areas.
In accordance with the classification of the World Conservation Union, there are 8 types of protected areas:
1. Reserve. The goal is to preserve nature and natural processes in an undisturbed state.
2. National Park. The goal is to preserve natural areas of national and international importance for scientific research, education and recreation. Usually these are large territories in which the use of natural resources and other material human influences are not allowed.
3. Monument of nature. These are usually small areas.
4. Managed natural reserves. The collection of certain natural resources is permitted under the supervision of the administration.
5. Protected landscapes and seaside views. This is a picturesque mixed natural and cultivated area with the preservation of traditional land use.
Protected area statistics usually include land in categories 1-5.
6.Resource reserve created to prevent premature use of the territory.
7. Anthropological reserve, created to preserve the traditional way of life of the indigenous population.
8. Territory of multipurpose use of natural resources, focused on the sustainable use of waters, forests, flora and fauna, pastures and tourism.
There are two additional categories that overlap the eight above.
9. Biosphere reserves. Created with the aim of preserving biological diversity. They include several concentric zones of varying degrees of use: from a zone of complete inaccessibility (usually in the central part of the reserve) to a zone of reasonable, but rather intensive exploitation.
10. World Heritage Sites. Created to protect the unique natural features of global importance. Management is carried out in accordance with the World Heritage Convention.
In total, there are about 10,000 protected areas (categories 1-5) in the world with a total area of 9.6 million km, or 7.1% of the total land area (excluding glaciers). The goal that the World Conservation Union sets for the world community is to achieve the expansion of protected areas to the size of 10% of the area of each large plant formation (biome) and, therefore, the world as a whole. This would contribute not only to the protection of biodiversity, but also to increase the resilience of the geographic environment in general.
The strategy of expanding the number and extent of protected areas is in conflict with the use of land for other purposes, especially in view of the growing population of the world. Therefore, in order to protect biological diversity, it is necessary, along with protected areas, to increasingly improve the use of “normal” inhabited lands and the management of populations of wild species, and not only endangered ones, and their habitats on such lands. It is necessary to apply such techniques as the zoning of territories according to the degree of use, the creation of corridors connecting land masses with less anthropogenic pressure, reducing the degree of fragmentation of biodiversity hotspots, managing ecotones, preserving natural waterlogged lands, managing populations of wild species and their habitats.
Bioregional management of large territories and water areas, as well as international agreements on this issue, are among the effective ways to protect biological diversity. The UN Conference on Environment and Development (1992) adopted the International Convention for the Protection of Biological Diversity.
An important agreement is the Convention on International Trade in Endangered Species of Wild Fauna and Flora. There are also a number of other conventions that protect various aspects of biological resources and biodiversity: the Convention on the Conservation of Migratory Species of Wild Animals, the Convention on the Conservation of Wetlands, the Convention on the Protection of Whales, etc. Along with the global conventions, there are numerous regional and bilateral agreements regulating specific biodiversity issues.
Unfortunately, so far it can be stated that, despite numerous measures, the accelerated erosion of the world's biological diversity continues. However, without these safeguards, the rate of loss of biodiversity would be even greater.
