Modern idea of the organic world. Presentation on biology "Modern ideas about the evolution of the organic world" (grade 9). “Only the spring waters will rush in, and without that they are dying in the hundreds...” Nekrasov

Modern evolutionary teaching is often called synthetic, because it includes not only Darwinism (i.e. Charles Darwin’s doctrine of selection and the struggle for existence), but also data from genetics, systematics, morphology, biochemistry, physiology, ecology and other sciences. The discoveries made in genetics and molecular biology turned out to be especially valuable for understanding the essence of evolution.

The chromosome theory and gene theory revealed the nature of mutations and the laws of transmission of heredity, and molecular biology and molecular genetics have established ways to store, implement and transmit genetic information using DNA. It was determined that The elementary evolutionary unit capable of responding to environmental changes by restructuring its gene pool is a population. Therefore, it is not the species, but its populations that are saturated with mutations and serve as the main material of the evolutionary process, which occurs under the influence of natural selection.

The modern doctrine of evolution is based on the population idea .

A population is a structural unit of a species. It represents a set of individuals of a species that have a common gene pool and occupy a certain territory within the range of this species.

Gradually, a divergence occurs between such populations ( divergence ) according to a number of genetic characteristics that accumulate through combinations and mutations. Gradually, individuals of populations acquire noticeable differences from the original parent species. If the differences that appear ensure that individuals of one population do not interbreed with individuals of other populations of the original species, then the isolated population becomes an independent new species, isolated by divergence from the original view.

In modern evolutionary teaching, a distinction is made between elementary units of evolution, elementary material and elementary factors of evolution.

Elementary unit evolution serves population. Each population is characterized by such properties as area, number and density, genetic heterogeneity of individuals, age and sex structure, special functioning in nature (intra-population and inter-population contacts, relationships with other species and with the external environment).

Elementary material evolution is served by hereditary variability - combinative and mutational.

These two types hereditary variability lead to the emergence of both qualitative and quantitative phenotypic differences between organisms.

Under certain conditions and over a period of time, new heritable traits that have arisen can reach fairly high concentrations in one or more adjacent populations of the species. Groups with special characteristics that have arisen in this way can be found in some territory within the species' range.

Different types.

Elementary factors of evolution- this is natural selection, mutation process, population waves and isolation.

Natural selection eliminates from the population individuals with unsuccessful combinations of genes and preserves individuals with genotypes that do not disrupt the process of adaptive morphogenesis. Natural selection guides evolution.

Mutation process maintains genetic heterogeneity of natural populations.

Population waves supply mass quantities of elementary evolutionary material for natural selection. Each population is characterized by a certain fluctuation in the number of individuals, either increasing or decreasing. In 1905, the Russian geneticist Sergei Sergeevich Chetverikov called these fluctuations waves of life.

Insulation provides barriers to prevent free interbreeding of organisms . It can be caused by territorial-mechanical (spatial, geographic) or biological (behavioral, physiological, environmental, chemical and genetic) incompatibility.

Breaking the crossbreeding insulation divides the original population into two or more, different from each other, and consolidates the differences in their genotypes. The separated parts of the population are already independently subject to the action of natural selection.

Isolation, mutation process and population waves, being factors of evolution, influence its course, but do not direct evolution.

The direction of evolution is provided by natural selection.

All types arose in the process evolution and continue to evolve. But there are organisms populations which are so well adapted to their environment that their species characteristics have remained virtually unchanged for tens and hundreds of millions of years. These include the first autotrophs - blue-green algae, the descendants of the first cartilaginous fish - sharks, the same age as dinosaurs - crocodiles. For more than four hundred million years in Africa, South America And Australia, almost unchanged, are inhabited by fish that can breathe not only with gills, but also through a swim bladder, not much different from real lungs. They have adapted perfectly to drought, which lasts in those places from 6 to 9 months a year. When reservoirs dry up, these fish (protoptera) go into hibernation - they fall asleep with their nose up in peculiar burrows dug in the muddy bottom, until the rainy season wakes them up. However, in a laboratory experiment, the experimental fish slept without water and food for more than 3 years... Explains the mysteries of the appearance of such amazing natural phenomena modern theory evolution.

The topic of the lesson is “ Modern representations about evolution organic world».

The basis of these ideas is “The Evolutionary Theory of Charles Darwin.” However, Darwin proposed his theory 150 years ago, and since then many things have happened. most important discoveries population ecology, genetics, molecular biology. The most important of them were: the rediscovery of G. Mendel’s laws at the beginning of the twentieth century, the introduction of the concept of the gene by W. Johansen, the formulation of T. Morgan’s chromosomal theory of inheritance, the mutation theory of G. Friese, the population ideas of S. S. Chetverikov and many others () ( see Fig. 1, 2).

Rice. 1

Rice. 2

The first discoveries of genetics, namely the genetic nature of heredity and mutation theory, caused a crisis in evolutionary theory. Scientists time could not correctly combine these discoveries and the provisions of the theory of evolution. A major breakthrough in the field of evolutionary ideas was the work of the English biologist J. Huxley () - “Evolution - a modern synthesis.” It served as an impetus for the formulation of the synthetic theory of evolution. At the moment, the synthetic theory of evolution contains the following provisions:

1. The material for the evolutionary process is mutations, as well as their combinations during the sexual process.

2. The main driving force of evolution is natural selection, which arises against the background of the struggle for survival.

Overpopulation is no longer the driving force behind evolution, as Darwin previously assumed.

3. The smallest unit of evolution is the population.

One individual is not capable of reproduction and transmission of its characteristics to offspring, therefore the individual cannot be considered as a unit of evolution.

4. Evolution is divergent in nature, that is, as a rule, one species gives rise to several other species at once.

5. Evolution is gradual and long-term.

Speciation is a continuous sequence of changes in different characters. It is impossible to distinguish the beginning and end of speciation.

6. A species is a collection of populations.

Gene flow is possible between populations as a result of interbreeding. When gene flow is interrupted for some reason, we speak of isolation. Isolation leads to the accumulation of differences between populations and, ultimately, to speciation.

7. Macroevolution follows the same path as microevolution.

There are no specific paths of macroevolution that would not be characteristic of microevolution.

8. All taxa are of monophyletic origin.

This means that all species of the same taxon have a common ancestor.

9. Evolution has an undirected course, that is, its movement is not subject to any logic.

Indeed, completely identical populations that have undergone isolation will, as a rule, develop in completely independent directions.

These provisions of modern evolutionary theory help explain the diversity of species on Earth. However, there is still a lot of experimental data that contradicts these theses. But let's hope that further discoveries can overcome these contradictions.

Experiments of the first evolutionists

Modern synthetic evolutionary theory is based on hundreds of complex genetic and molecular biological experiments. At the same time, it practically does not contradict Darwin’s basic theory of evolution in any way. It is completely incomprehensible how one scientist was able to create this theory 150 years ago, without even relying on such concepts as a gene or a chromosome. Darwin's genius lies in the fact that he created his theory based only on paleontological method and the method of observing wildlife.

Preventing the Collapse of Darwinism

Huxley's work - "Evolution - a modern synthesis" practically saved Darwinism from collapse (see Fig. 3). The fact is that in the middle of the century, many scientists were ready to abandon Darwinism, based only on the fact that some experiments contradicted it. However, Huxley was able to prove that these experiments not only do not contradict Darwinism, but, moreover, confirm it.

Rice. 3

Experiment confirming microevolution

Evolution is practically inaccessible to experiment. The change of generations in living beings lasts months, years or even decades, so keep track of evolutionary path some kind is simply impossible. A great success in the field of evolution experiments has been the observation of microorganisms. The fact is that a new generation of E. coli is formed in 10 - 20 minutes, so within a few days, weeks or months a huge number of generations can be accumulated (see Fig. 4). At this scale, mutations will be sufficiently pronounced to allow their role in natural selection to be assessed. These experiments brilliantly confirmed Darwin's theory of evolution.

Rice. 4

References

Mamontov S.G., Zakharov V.B., Agafonova I.B., Sonin N.I. Biology. General patterns. - M.: Bustard, 2009.
Pasechnik V.V., Kamensky A.A., Kriksunov E.A. Biology. Introduction to general biology and ecology. Textbook for 9th grade. 3rd ed., stereotype. - M.: Bustard, 2002.
Ponomareva I.N., Kornilova O.A., Chernova N.M. Basics general biology. 9th grade: Textbook for 9th grade students. educational institutions/ Ed. prof. I.N. Ponomareva. - 2nd ed., revised. - M.: Ventana-Graf, 2005.

Homework

What discoveries were associated with the crisis of Darwinism at the beginning of the twentieth century?
Why does classical genetics contradict Darwinism?
Are you convinced by the evolutionist evidence?
What particular theories were united by J. Huxley’s synthetic theory of evolution?

Modern evolutionary teaching is often
called synthetic because it
includes not only Darwinism (i.e. the teaching
Charles Darwin on selection and the struggle for existence),
but also data from genetics, systematics, morphology,
biochemistry, physiology, ecology and other sciences.
Particularly valuable for understanding the essence
evolution were discoveries made in
genetics and molecular biology.

Chromosome theory and gene theory revealed the nature
mutations and laws of transmission of heredity, and molecular
biology and molecular genetics have established ways
storage, implementation and transfer of genetic information from
using DNA.
It was determined that elementary
evolutionary unit capable of responding to changes
environment, the restructuring of its gene pool is the population.
Therefore, it is not the species, but its populations that are saturated with mutations and serve
the main material of the evolutionary process going under
the action of natural selection.

The modern doctrine of evolution is based on the population idea.

A population is a structural unit of a species. She represents
a collection of individuals of a species that have a common gene pool and
occupying a certain territory within the range of this species.

Gradually between such populations
there is a divergence (divergence) in
a number of genetic traits that
accumulate through combinations and mutations.
Gradually, individuals of populations acquire
noticeable differences from the original
parent species. If appeared
differences ensure non-crossbreeding
individuals of one population with individuals of others
populations of the original species, then the isolated
the population becomes independent
a new species, isolated by
divergence from the original species.

In modern evolutionary teaching, elementary units of evolution, elementary material and elementary factors are distinguished

evolution.
The elementary unit of evolution is the population.
Each population is characterized by such properties as
range, number and density, genetic
heterogeneity of individuals, age and sex structure,
special functioning in nature
(intrapopulation and interpopulation contacts,
relationships with other species and with the external environment).

Sexual contacts between
individuals within one
populations are carried out
much easier and more often than
with individuals different populations
the same type.

Therefore, changes that accumulate in one population with
through recombination, mutation and natural selection,
determine its qualitative and reproductive isolation
(divergence) from other populations.
Changes in individual individuals do not lead to evolutionary
changes, since a significant accumulation of similar
heritable characteristics, and this is only available to the whole
group of individuals, which is a population.

The elementary material of evolution is hereditary variability - combinative and mutational.

Elementary material
evolution serves
hereditary variability is combinative and mutational.
These two types of hereditary
variability leads to
emergence as
quality and
quantitative
phenotypic differences
organisms.

Under certain conditions
and for some time
new ones have arisen over time
heritable traits can
achieve enough
high concentrations in
one or more
adjacent populations of the species.
Arising in this way
groups with special characteristics
can be found on
some territory inside
species range.
Finches.
Different types.

Basic provisions of synthetic
theories of evolution
The material for evolution is hereditary
variability.
Basic driving factor evolution natural selection arising on the basis
struggle for existence.
The smallest unit of evolution is a population.

Evolution
wears
V
most
cases
divergent nature, i.e. one taxon can become
ancestor of several daughter taxa.
Evolution is gradual and long-term
character.
A species consists of many subordinates,
morphologically, physiologically, ecologically,
biochemically and genetically different, but
reproductively not isolated units -
subspecies and populations.

The species exists as a whole and closed
education. View integrity is maintained
migrations of individuals from one population to another,
in which an exchange of alleles is observed (“flow
genes").
Evolution is irreversible. Each
evolutionary change is a combination of many
independently arising and selection rearrangements in the genotype. Because
returning to the original source type is not possible. Necessary
also take into account that it is not individuals that evolve, but populations that are selected
not individual signs, but complexes of signs, and are controlled
selection of entire gene complexes.

The elementary factors of evolution are natural selection, the mutation process, population waves and isolation.

Natural selection eliminates individuals from a population with
unsuccessful combinations of genes and preserves individuals with
genotypes that do not disrupt the process
adaptive morphogenesis. Natural
selection guides evolution.
The mutation process maintains the genetic
heterogeneity of natural populations.

Insulation provides barriers to prevent free
crossing of organisms. It can be caused by territorial-mechanical (spatial, geographic) or biological
(behavioral, physiological, environmental, chemical and
genetic) incompatibility.

Breaking crossbreeding, isolation
dismembers the original population
into two or more, different from each other
from each other, and reinforces differences in
their genotypes. Divided parts
populations are already on their own
exposed to
natural selection.

Population waves
supply mass quantities
elementary evolutionary
material for natural selection.
Each population has
certain fluctuation
the number of individuals to the side then
increase, then decrease. These
fluctuations in 1905 Russian
geneticist Sergei Sergeevich
Chetverikov called them the waves of life.

Types of population waves:

Periodic (for example, seasonal fluctuations)
number of insects, annual plants, viruses
flu)
Non-periodic (depend on many factors). Examples:
fluctuations in predator-prey numbers, outbreaks
number of lemmings in the Arctic, locust swarms,
breeding rabbits in Australia, plague epidemics in
Europe in the past.

Genetic drift - elementary
evolutionary factor.
Genetic drift refers to random
changes in gene frequencies caused by low
population size.
When the number of individuals is small, they stop
Mendel's laws are fulfilled.

Genetic drift

Thus, genetic drift can lead to:

Increased homozygosity of the population;
Preservation of harmful alleles despite
selection;
Reproduction of rare alleles;
Complete disappearance of any
alleles.

“Only the spring waters will rush in, and without that they are dying in the hundreds...” Nekrasov

Only a few survive
individuals, and
fitness is not
plays a role, rather chance
(represented by D. Mazaya)

The founder effect is another cause of genetic drift. In this case, several individuals (or even one, but pregnant) colonize a new place

An example of the founder effect in humans:

The Mennonite sect in Pennsylvania, USA now numbers
about 8,000 people, all descendants of three married couples,
emigrated in 1770. 13% of them suffer from rare
a form of dwarfism with multiple fingers. Apparently one of
ancestors was a heterozygous carrier of this mutation.

Isolation, mutation process and
population waves, being
factors of evolution, influence its course,
but they do not guide evolution.
The direction of evolution provides
natural selection.

Modern evolutionary teaching is often called synthetic because it includes not only Darwinism (i.e. Charles Darwin’s teaching about selection and the struggle for existence), but also data from genetics, systematics, morphology, biochemistry, physiology, ecology and other sciences . The discoveries made in genetics and molecular biology turned out to be especially valuable for understanding the essence of evolution.

Chromosomal theory and gene theory revealed the nature of mutations and the laws of transmission of heredity, and molecular biology and molecular genetics established methods for storing, implementing and transmitting genetic information using DNA. It was determined that the elementary evolutionary unit capable of responding to environmental changes by restructuring its gene pool is a population. Therefore, it is not the species, but its populations that are saturated with mutations and serve as the main material for the evolutionary process, which occurs under the influence of natural selection.

The modern doctrine of evolution is based on the population idea. A population is a structural unit of a species. It represents a set of individuals of a species that have a common gene pool and occupy a certain territory within the range of this species.

Gradually, divergence (divergence) occurs between such populations in a number of genetic traits that accumulate through combinations and mutations. Gradually, individuals of populations acquire noticeable differences from the original parent species. If the differences that appear ensure that individuals of one population do not interbreed with individuals of other populations of the original species, then the isolated population becomes an independent new species, isolated through divergence from the original species.

In modern evolutionary teaching, a distinction is made between elementary units of evolution, elementary material and elementary factors of evolution. The elementary unit of evolution is the population. Each population is characterized by such properties as area, number and density, genetic heterogeneity of individuals, age and sex structure, special functioning in nature (intrapopulation and Sexual contacts between individuals within the same population are carried out much easier and more often than with individuals of different populations of the same species. Therefore, changes that accumulate in one population through recombinations, mutations and natural selection determine its qualitative and reproductive isolation (divergence) from other populations. Changes in individual individuals do not lead to evolutionary changes, since a significant accumulation of similar heritable characteristics is required. this is available only to an integral group of individuals, which is a population.

Elementary materialevolution is served by hereditary variability - combinative and mutational. These two types of hereditary variability lead to the emergence of both qualitative and quantitative phenotypic differences between organisms.

Elementary factors of evolution- this is natural selection, mutation process, population waves and isolation. Natural selection eliminates from the population individuals with unsuccessful combinations of genes and preserves individuals with genotypes that do not disrupt the process of adaptive morphogenesis. Natural selection guides evolution. The mutation process maintains the genetic heterogeneity of natural populations.

Population wavessupply mass quantities of elementary evolutionary material for natural selection. Each population is characterized by a certain fluctuation in the number of individuals, either increasing or decreasing. In 1905, the Russian geneticist Sergei Sergeevich Chetverikov called these fluctuations waves of life.

Insulation provides barriers that prevent free interbreeding of organisms. It can be caused by territorial-mechanical (spatial, geographic) or biological (behavioral, physiological, environmental, chemical and genetic) incompatibility.

By disrupting crossing, isolation divides the original population into two or more that differ from each other, and perpetuates the differences in their genotypes. The separated parts of the population are already independently subject to the action of natural selection.

Isolation, mutation process and population waves, being factors of evolution, influence its course, but do not direct evolution.The direction of evolution is provided by natural selection.

The presentation “Modern ideas about the evolution of the organic world” was compiled according to Ponomareva’s student I.N. "Fundamentals of General Biology". The presentation material corresponds to the material of the paragraph and complements its content. A series of videos will help students understand the lesson material.

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Modern ideas about the evolution of the organic world Biology teacher MBOU - gymnasium No. 39 Mokina Irina Vladimirovna. Yekaterinburg

Chromosomal theory and gene theory revealed the nature of mutations and the laws of transmission of heredity, and molecular biology and molecular genetics established methods for storing, implementing and transmitting genetic information using DNA. It was determined that the elementary evolutionary unit capable of responding to environmental changes by restructuring its gene pool is a population. Therefore, it is not the species, but its populations that are saturated with mutations and serve as the main material of the evolutionary process, which occurs under the influence of natural selection.

Sexual contacts between individuals within the same population are much simpler and more frequent than with individuals from different populations of the same species.

Therefore, changes that accumulate in one population through recombination, mutation and natural selection determine its qualitative and reproductive isolation (divergence) from other populations. Changes in individual individuals do not lead to evolutionary changes, since a significant accumulation of similar heritable traits is required, and this is only available to an integral group of individuals, such as a population.

The elementary material of evolution is hereditary variability - combinative and mutational. These two types of hereditary variability lead to the emergence of both qualitative and quantitative phenotypic differences between organisms.

The elementary factors of evolution are natural selection, the mutation process, population waves and isolation. Natural selection eliminates from the population individuals with unsuccessful combinations of genes and preserves individuals with genotypes that do not disrupt the process of adaptive morphogenesis. Natural selection guides evolution. The mutation process maintains the genetic heterogeneity of natural populations.

Population waves supply mass quantities of elementary evolutionary material for natural selection. Each population is characterized by a certain fluctuation in the number of individuals, either increasing or decreasing. In 1905, the Russian geneticist Sergei Sergeevich Chetverikov called these fluctuations waves of life.

Isolation provides barriers that prevent organisms from interbreeding freely. It can be caused by territorial-mechanical (spatial, geographic) or biological (behavioral, physiological, environmental, chemical and genetic) incompatibility.

Isolation, mutation process and population waves, being factors of evolution, influence its course, but do not direct evolution. The direction of evolution is provided by natural selection.

Modern idea of ​​the organic world. Presentation on biology "Modern ideas about the evolution of the organic world" (grade 9). “Only the spring waters will rush in, and without that they are dying in the hundreds...” Nekrasov