Biology presentation driving forces of evolution. Presentation “The main driving forces of evolution. Checking homework

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Lesson Objectives: To introduce students to various forms struggle for existence; To teach correctly to determine the forms of the struggle for existence; Convince that natural selection is the main driving force of evolution.

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Examination homework. What form of natural selection usually operates in populations of species living in relatively unchanging environmental conditions? Give her a description. If, as a result of natural selection, individuals that deviate from the norm in their structure die, then what form of selection can take place in this case? Give her a description.

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Forms of the struggle for existence Intraspecific struggle Interspecific struggle Struggle against adverse environmental conditions

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Intraspecific struggle Leads to the preservation of the population and species due to the death or non-participation in reproduction of the least adapted individuals of this species.

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Examples of intraspecific struggle: Fight for territory; Competition for prey; Intraspecific cannibalism; Fight for dominance in the pack; Fight for possession of a female

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Interspecific struggle Leads to the victory of a more viable individual or population of one species over a less viable individual or population of another species.

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Struggle with adverse environmental conditions Leads to the survival of the most adapted individuals, populations and species in the changed conditions of inanimate nature.

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Examples of dealing with adverse conditions environment: Seasonal molt; Summer and winter hibernation; Seasonal flights and migrations of birds; Strongly developed root system and modified leaves in desert plants; Short stature of birch and willow in tundra conditions.

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Fixing the topic: Write down the serial numbers of the reasons leading to the death of dandelion individuals in three lines: A - Intraspecific struggle B - Interspecific struggle C - Fight against adverse environmental conditions

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Causes of death of dandelion individuals: 1- fruits, along with hay, enter the stomach of a sheep; 2-many birds eat fruits; 3-seedlings feed on herbivores; 4-dandelions are trampled by people; 5- plants darken wheatgrass, nettle; 6-dandelions themselves crowd out each other; 7-seeds perish on the rocks, in the desert; 8-seeds do not germinate due to lack of moisture; 9-plants die from severe frosts; 10-plants die from pathogenic bacteria and viruses.

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Answer the questions: In nests of owls you can often find chicks of different ages. In the snowy owl, older chicks appear in June, and younger chicks in July. In the eagle owl, all the chicks are older than one another by 5-7 days. What is the biological significance of this phenomenon? What provisions of evolutionary doctrine can explain the features of reproduction of birds of prey?

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Cod fry often settle under the bell of some species of jellyfish, whose tentacles are poisonous. How could such a phenomenon occur? With the help of what provisions of evolutionary theory can such a “strangeness” of the behavior of cod fry be explained?

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driving forces evolution

The development of evolutionary ideas The author of the first coherent evolutionary concept was Charles Darwin, who wrote a book on this subject: "On the Origin of Species by Means of Natural Selection, or on the Preservation of Favorable Breeds in the Struggle for Life" Charles Darwin (1809 - 1882)

The main provisions of the evolutionary doctrine 1. Within each species of living organisms, there is a huge range of individual hereditary variability in morphological, physiological, behavioral and any other characteristics. This variability may be continuous, quantitative, or discontinuous qualitative, but it always exists. 2. All living organisms reproduce exponentially. 3. Life resources for any kind of living organisms are limited, and therefore there must be a struggle for existence either between individuals of the same species, or between individuals different types or with natural conditions. In the concept of "struggle for existence" Darwin included not only the actual struggle of an individual for life, but also the struggle for success in reproduction.

Basic provisions of the evolutionary doctrine 4 . In the conditions of the struggle for existence, the most adapted individuals survive and give offspring, having those deviations that accidentally turned out to be adaptive to given environmental conditions. This is a fundamentally important point in Darwin's argument. Deviations do not occur in a directed way - in response to the action of the environment, but by chance. Few of them are useful in specific conditions. The descendants of a surviving individual who inherit a beneficial variation that allowed their ancestor to survive are better adapted to the environment than other members of the population. 5. Survival and preferential reproduction of adapted individuals Darwin called natural selection. 6. The natural selection of individual isolated varieties under different conditions of existence gradually leads to divergence (divergence) of the characteristics of these varieties and, ultimately, to speciation.

The basic logic of the evolutionary doctrine Heredity Variability The ability of organisms to reproduce indefinitely Limited environmental conditions Organisms differ from each other and can transmit their characteristics descendants Struggle for existence Survival of the fittest Natural selection

Natural selection As a result: Living systems adapt to environmental conditions There are a huge number of species of living organisms on planet Earth Highly organized species and species with a more primitive level of organization can coexist

Artificial selection Natural selection ELEMENTARY EVOLUTIONARY FACTORS

artificial selection

Artificial selection Preservation and reproduction of specimens of plants and animals that are in some way beneficial or useful to humans

Material for selection In the change of breeds of domestic animals and plants cultivated by people, two main points are involved: VARIABILITY, which provides material for breeding new breeds; HEREDITY - a common property of all living beings, thanks to which the characteristics of the parents are transmitted to offspring * Darwin personally studied all the breeds of domestic pigeons available to him and found that they all descended from a wild rock pigeon. From one form, setting special requirements each time when creating a new breed, people received both large pouts with high legs, and a small pigeon - a seagull, and carrier pigeons with their fast flight, and peacock pigeons with a fan-shaped tail, and many others.

Forms of artificial selection Unconscious selection is a selection in which the goal is not to create a new variety or breed. People keep the best, in their opinion, individuals and destroy (cull out) the worst. Unconscious selection arose long ago, from the moment of domestication of the dog. Unconscious selection leads to a change in plants and animals, to the improvement of breeds and varieties, to the creation of new local breeds and varieties. The desired result with this selection is formed slowly, but it can be impressive. Methodical selection is a selection carried out by a person according to a certain plan, with purpose- Creation of a breed or variety. Features: the goal is set: the breeder decides which traits need to be changed and in which direction, i.e., the direction of selection is determined (egg production, fleshiness, beautiful crest, beautiful tail, beautiful plumage); a plan is drawn up for creating a breed (variety): what breeds (varieties) and in what order should be crossed, what types of crossbreeding should be used; created special conditions life; methodological selection is creativity.

NATURAL SELECTION individual differences and changes and destruction of harmful ones, I have called natural selection or the survival of the fittest. C. Darwin

The mechanism of natural selection 1. Changes in genotypes in a population are diverse, they affect any signs and properties of organisms. 2. Among the many changes, there are random ones that are better suited to specific natural conditions in given time. 3. Those with these beneficial traits leave more surviving and breeding offspring than the rest of the population. 4. From generation to generation, useful changes are summed up, accumulated, combined and turned into adaptations - adaptations.

Scope of natural selection Natural selection affects all traits of an individual. Selection proceeds according to phenotypes - the results of the realization of the genotype in the process of ontogenesis in specific environmental conditions, i.e., selection acts only indirectly on genotypes. The field of action of natural selection is populations. The point of application of natural selection is a trait or property.

Natural selection has two sides: differential (selective) survival differential mortality *i.e. natural selection has positive and negative sides. The negative side of natural selection is elimination. The positive side is the preservation of the phenotypes most appropriate to the conditions of the ecosystem at the moment. *Natural selection increases the frequency of these phenotypes, and hence the frequency of the genes that form these phenotypes.

Struggle for existence

What causes the struggle for existence? One dandelion plant occupies an area of 10 m 2 on the ground and produces 100 flying seeds per year. a) How many square kilometers of area will cover all the offspring of one dandelion in 10 years, provided that it reproduces unhindered in a geometric progression? (1 x 10 12 km 2) b) Will there be enough space for these plants on the surface of the globe for the 11th year? (the surface area of the globe is 510 million km 2) c) Will this species completely cover at least one continent? Why? The main reason for the struggle is the discrepancy between the ability of species to reproduce indefinitely and the limited resources.

Forms of the struggle for existence Interspecific intraspecific struggle with adverse environmental conditions

Intraspecific struggle for existence Individuals of the same species have similar needs In territory In reproduction In food

Intraspecific struggle Leads to the preservation of the population and species due to the death or non-participation in reproduction of the least adapted individuals of this species.

Examples of intraspecific struggle: Fight for territory; Competition for prey; Intraspecific cannibalism; Fight for dominance in the pack; Fight for possession of a female

Interspecific struggle Leads to the victory of a more viable individual or population of one species over a less viable individual or population of another species.

Struggle with adverse environmental conditions Leads to the survival of the most adapted individuals, populations and species in the changed conditions of inanimate nature.

Coping with adverse environmental conditions Drought in the savanna Low temperatures Lack of light Alkaline gut

Examples of dealing with adverse environmental conditions: Seasonal molt; Summer and winter hibernation; Seasonal flights and migrations of birds; Strongly developed root system and modified leaves in desert plants; Short stature of birch and willow in tundra conditions.

MOVING. Propulsive selection - a form of natural selection that operates under a directional change in conditions external environment. In this case, individuals with traits that deviate in a certain direction from the average value receive advantages. In this case, other variations of the trait are subjected to negative selection. As a result, in the population from generation to generation, there is a shift in the average value of the trait in a certain direction. At the same time, the pressure of driving selection must correspond to the adaptive capabilities of the population and the rate of mutational changes. A modern case of motive selection is the "industrial melanism of English butterflies". . It preserves hereditary changes in a certain direction, shifting the rate of reaction accordingly. For example, when developing the soil as a habitat for various unrelated groups of animals, the limbs turned into burrowing ones.

STABILIZING. Stabilizing selection is a form of natural selection in which the action is directed against individuals with extreme deviations from the average norm in favor of individuals with an average severity of the trait. Many examples of the action of stabilizing selection in nature have been described. For example, at first glance it seems that individuals with maximum fecundity should make the greatest contribution to the gene pool of the next generation. However, observations of natural populations of birds and mammals show that this is not the case. The more chicks or cubs in the nest, the more difficult it is to feed them, the smaller and weaker each of them. As a result, individuals with average fecundity turn out to be the most adapted. Selection in favor of averages has been found for a variety of traits. In mammals, very low and very high birth weight newborns are more likely to die at birth or in the first weeks of life than middle weight newborns.

SEXUAL. Sexual selection is natural selection for success in reproduction. In males of many species, pronounced secondary sexual characteristics are found, which at first glance seem to be maladaptive: a peacock's tail, bright feathers birds of paradise and parrots, scarlet combs of roosters, enchanting colors of tropical fish, songs of birds and frogs, etc. Many of these features make life difficult for their carriers, making them easily visible to predators.

DISRUPTIVE. Disruptive (tearing) selection is a form of natural selection in which conditions favor two or more extreme variants (directions) of variability, but do not favor the intermediate, average state of the trait. As a result, several new forms may appear from one initial one. The formation of seasonal races in some weeds is explained by the action of disruptive selection. It was shown that the timing of flowering and seed ripening in one of the species of such plants - meadow rattle - stretched almost all summer, and most of the plants bloom and bear fruit in the middle of summer. However, in hay meadows, those plants that have time to bloom and produce seeds before mowing, and those that produce seeds at the end of summer, after mowing, receive advantages. As a result, two races of rattle are formed - early and late flowering.

Comparative signs Natural selection Artificial selection 1. Selecting factor Conditions of the external environment Man 2. Results of the variety of species, their fitness to the diversity of the variety of varieties of plants and rocks of animals, their fitness to human needs 3. Duration of action is constant, thousands of years about 10 years (elimination time Sorts or breeds) 4. Object of action Position separate individuals or their groups 5. Place of action Natural ecosystems Research institutions (breeding stations, tribal farms) 6. Selection forms Driving, stabilizing, dioretical, sexual unconscious, Methodical 7. Selection material HEREDITARY VARIATION HEREDITARY VARIABILITY

Development of evolutionary ideasAuthor
first
slender
evolutionary concept was
Charles Darwin, who wrote
about this book:
"On the Origin of Species by
natural selection or
conservation
favorable breeds in
fight for life"
Charles Darwin (1809 - 1882)

The driving forces of evolution are heredity, variability,
natural
selection
Heredity
property of living organisms to transmit
traits from parents to offspring.
Variability
property of living organisms to acquire
new signs in the development process.

Natural selection is the survival and leaving of offspring by the fittest individuals and the death of the less fit.

The struggle for existence is
intraspecific and interspecific
relationships and relationships
organisms with environmental factors.

The basic logic of evolutionary teaching

Heredity
Variability
Organisms are different
from each other and can
transfer their
characteristic
features for descendants
survive
most
adapted
Ability
organisms to
unlimited
reproduction
Limitation
environmental conditions
Struggle for
Existence
Natural
selection

Eventually:

live
systems
adapt
to
conditions
environmental
environments
Natural
selection
On the
planet
Earth
exists
huge
number of living species
organisms
Can
coexist
high
organized
views and views from over
primitive
level
organizations

Evidence for Evolution: Paleontological

archeopteryx

Archeopteryx

Evidence for Evolution: Transitional Forms

Evidence for evolution: Morphological (comparative anatomical)

Homologous and similar organs

Rudiments and atavisms

Evidence for evolution: embryological

Karl Baer: the law of germline similarity

Forms of struggle for existence

Intraspecific struggle
Interspecies struggle
Fight against adverse
environmental conditions

Intraspecific struggle

Leads
to
conservation
populations and species
check
death
or
non-participation
in
reproduction
least
adapted
individuals of this species.
Label for guinea pigs.lnk

Examples of intraspecific struggle

Struggle for
territory;
Competition for
prey;
Intraspecific
cannibalism;
The struggle for dominance
in a flock;
Struggle for possession
female

Interspecies struggle

Leads to victory
more
viable
individuals
or
populations
one
kind
above
less
viable
individual
or
population of another
kind.

Examples of interspecific struggle:

crowding out
bees
Australian bee
European;
Competition
between
gray
And
black
rats;
competition for light
between spruce and birch;
Parasitism;
The displacement of the sable marten from his
habitual
places
habitat.

Fight against adverse environmental conditions

Examples of dealing with adverse conditions
environment:
Seasonal molt;
Summer and winter
hibernation;
seasonal flights and
migrations of birds;
highly developed
root system and
modified leaves
in desert plants;
The stunted birch and
willows in the tundra.

Examples of dealing with adverse environmental conditions:

Summarizing:
Struggle for
Existence
"Defeat" least
adapted
individuals who have
unfavorable
signs
"Victory" most
adapted
individuals who have
favorable
signs
Death, elimination
from breeding
Survival and
participation
in reproduction
Adverse
signs
not transmitted
offspring
Favorable
signs are transmitted
offspring and
intensify

Summarizing:

driving forces
evolution:
Natural
selection
Struggle for
Existence
hereditary
variability
result
fight for
Existence
is an
natural selection

Driving Forces of Evolution:

microevolution
This
process
transformations
population or populations under
by the factors of evolution,
which the
leads
to
change
gene pool and the formation of a new
kind.

microevolution

1. Under the influence of elementary factors
on the gene pool of the population occurs
frequency change
individual genes. This
leads
to
elementary
evolutionary phenomenon - change
genotypic and phenotypic
composition of the population.
2. Long-term unidirectional
impact
natural
selection
observed
differentiation
populations.

Evolutionary factors are any
phenomena and processes that
any effect on evolution
Factors
evolution
Mutations
Drifting
genes
Waves
life
Insulation

This
process
in which
committed
sudden,
natural or caused
artificially
hereditary
changes
in
genetic
material,
leading
to
change in individual signs
organism.

mutation process

S.S. Chetverikov was one of the first
who drew attention to periodic
fluctuations
numbers
individuals
constituting the population.
Such
SHAKE
NUMBERS
INDIVIDUALS
POPULATIONS
received
title
"POPULATION
WAVES" or "WAVES OF LIFE".
CAUSES
CHANGES
NUMBERS
POPULATIONS:
dramatic climate change,
fodder base, natural disasters,
human economic activity and
others

1. Waves can be completely random
and drastically change in the population
concentration
seldom
occurring genes or entire
genotypes.
2. During a period of sharp decline
population size some
genes (genotypes) can completely
disappear, regardless of
their biological value.
3. As the waves rise, other genes
sharply increase their concentration.
Waves of life, just like mutation
process, deliver random
non-directional
genetic
material
for
natural
selection.

1. Periodic (for example, seasonal fluctuations
number of insects, annual plants,
flu viruses)
2. Non-periodic
(depend
from
many
factors). Examples: population fluctuations
predator - prey, outbursts
lemmings in the Arctic, passages of locusts,
rabbit breeding in Australia, plague
epidemics in Europe in the past.

Types of population waves:

At the bottom of the abundance curve
there is a bottleneck effect.
Few individuals pass through it and in the new
population, the ratio of alleles will be different.

At the bottom of the abundance curve, there is a “bottleneck effect”. Few individuals pass through it and in the new population

“Only spring waters will rush, and without that they
hundreds of gins ... "
Nekrasov
Only survive
few individuals and
fitness is not
plays a role rather
case (represented by D. Mazaya)

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

Isolation is a violation of the freedom of crossing.
In an isolated group, allele frequencies
will be different than in a large population.
Isolation leads to genetic drift, and also
is the starting point for speciation.
Insulating
factor

Isolation is a violation of the freedom of crossing. In an isolated group, the allele frequencies will be different than in a large population. isolation drive

I.
potential
partners are not
meet
II.
potential
partners
meet, but
do not mate
Geographic
insulation
live in different
habitats
Ecological
(seasonal)
insulation
breed in
different dates
behavioral
insulation
differ in color
marriage rituals,
song or smell

Geographic isolation
Paradise magpies live in the rainforests of New Guinea.
Each of the five species lives on its own mountain range,
separated from the rest by the savannah. Morphological differences
between species are so significant that they were originally
described as separate genera.

Environmental isolation
Lake Tana (Ethiopia) inhabited by the complex
closely related species of barb fish.
Since other fish species in the lake are very
not enough, then the barbs have mastered all available
ecological niches.
Form eating mixed food
Predator
Produces insects, plankton and fish fry near the surface of the water

Biological dictation
1. Evolution
2. Heredity
3. Variability
4. Natural selection
5. Struggle for existence
6. Paleontological evidence
7. Embryological evidence
8 Rudiments
9. Microevolution
10. Mutation process
11. Population waves
12. Isolation summary of other presentations

"Natural selection according to Darwin" - Forms of natural selection. Types of struggle for existence. There is genetic variation. hereditary variability. disruptive selection. stabilizing selection. Heredity. Driving selection. Natural selection. Observation results. 1831 - C. Darwin goes on a trip around the world. Fight against adverse conditions. Interspecies struggle. Intraspecific struggle. Struggle for existence.

"Biology "Natural Selection"" - Final scheme. Natural selection is the result of the struggle for existence. Tasks. Disruptive form of selection. Driving form of selection. Stages of the lesson. Forms of natural selection. Consolidation of knowledge. Strengthening the ability to distinguish and characterize individual forms. Earth. The purpose of the lesson. Questions on Ch. Darwin. Natural selection. Knowledge check. Problem question. Stabilizing form of selection.

"Natural selection" - Stabilizing. As a result, individuals with average fecundity turn out to be the most adapted. Selection in favor of averages has been found for a variety of traits. Sexual. Many examples of the action of stabilizing selection in nature have been described. As a result, two races of rattle are formed - early and late flowering. Moving. Natural selection. As a result, several new forms may appear from one initial one.

"Struggle for existence, natural selection" - In territory. Natural selection is the driving force behind species change. Presentation on the topic: Natural selection. The first position of the theory. Alkaline environment of the intestine. Drought in the savannah. Intraspecific struggle for existence. The second position of the theory. Fight against adverse environmental conditions. In reproduction. In nature there is a continuous struggle for existence. The main provisions of Ch. Darwin's theory of natural selection.

"The main driving forces of evolution" - Examples of dealing with adverse environmental conditions. driving forces of evolution. The result of disruptive selection. Examples of interspecific struggle. Examples of intraspecific struggle. Fight against adverse environmental conditions. Forms of natural selection. The result of stabilizing selection. Provides adaptation of various groupings of individuals. Forms of the struggle for existence. Interspecies struggle. The result of motive selection.

"Types of natural selection" - The creative role of natural selection. Birth weight distribution in English infants. The concept of natural selection. An example of stabilizing selection. Polymorphism. Natural selection. An example of driving or directional selection. Adaptations are an example of the action of natural selection. An example of disruptive selection. Stock of genetic variability. Driving or directed selection. The principle of natural selection.

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