Struggle for existence. Driving forces of evolution.pptx - Presentation on the topic “Driving forces of evolution” (grade 10) Gene pool and driving forces presentation

• Biology 11th grade
• Subject line “Wildlife”
• MBOU gymnasium No. 44 named after. Deeva V.N.
• Teacher: Lavrenyuk Lyudmila Viktorovna

• G.Ulyanovsk

Driving forces of evolution. Struggle for existence. Natural selection.

Lesson topic:

• Convince students that natural selection is the main driving force of evolution;
• Study the forms of natural selection.
• Introduce students to various forms of struggle for existence;
• Teach how to apply the acquired knowledge when performing practical tasks.

Struggle for

existence

"Defeat" is the least

adapted

individuals having

unfavorable

signs

"Victory" is the most

adapted

individuals having

favorable

signs

Survival and

participation

in reproduction

Death, elimination

from reproduction

Favorable

signs are transmitted

offspring and

are intensifying

Unfavorable

signs

are not transmitted

posterity

Forms of struggle for existence:

Intraspecific struggle

Interspecies fight

Fight against unfavorable

environmental conditions

Pinning a topic:

• Exercise:
• Write down the serial numbers of the reasons leading to the death of dandelion individuals in three lines:

A – Intraspecific struggle

B – Interspecific struggle

B – Combating adverse environmental conditions

Causes of death of dandelion specimens:

1-many birds feed on fruits;

2-seeds die on rocks, in the desert;

3-seedlings feed on herbivores;

4-plants die from severe frosts;

5-dandelions are trampled by people;

6- plants darken wheatgrass, nettle;

7-dandelions themselves crowd out each other;

8-the fruits, along with the hay, enter the sheep’s stomach;

9-seeds do not germinate due to lack of moisture;

10-plants die from pathogenic bacteria and viruses.

B – 1, 3, 5, 6, 8,10

• In owl nests you can often find chicks of different ages. The polar owl's eldest chicks appear in June, and the youngest chicks appear in July. All the eagle owl's chicks are 5-7 days older than each other. What is the biological significance of this phenomenon? What principles of evolutionary teaching can explain the reproductive characteristics of birds of prey?

• Cod fry often settle under the bell of some types of jellyfish, the tentacles of which are poisonous.
• How could such a phenomenon arise?
• What principles of evolutionary theory can be used to explain such “strange” behavior of cod fry?

Forms of natural selection.

• Driving selection – ensures the adaptability of the population and species to unidirectional changes in the environment.

Individuals with extreme manifestations of the trait survive and reproduce.

Result of driving selection:

Industrial melanism of the birch moth, diversity in the beak structure of finches .

Individuals with an average manifestation of the trait survive and reproduce.

The result of stabilizing selection:

Correspondence of the body structure of the pollinating insect to the structure of the flower.

The structure of the crocodile's body has not changed for millions of years.

Individuals that have either of the two extreme manifestations of the trait survive.

The result of disruptive selection:

Differences in color between different

lake frog populations

• What form of natural selection usually operates in populations of species living in relatively constant 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.

Driving forces of evolution:

The result

fight for

existence

is

natural

selection

Natural

selection

Struggle for

existence

Hereditary

variability

• Answer questions on the page
• 375-376, 391.

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“Natural selection according to Darwin” - Forms of natural selection. Types of struggle for existence. There is hereditary variability. Hereditary variability. Disruptive selection. Stabilizing selection. Heredity. Driving selection. Natural selection. Observation results. 1831 - Charles Darwin goes on a trip around the world. Fighting 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. Lesson stages. Forms of natural selection. Consolidation of knowledge. Consolidating the skills to distinguish and characterize individual forms. Earth. The purpose of the lesson. Questions about Charles Darwin. Natural selection. Check of knowledge. Problematic question. Stabilizing form of selection.

“Natural selection” - Stabilizing. As a result, individuals with average fertility are the most fit. Selection toward the mean 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 original one.

“The struggle for existence, natural selection” - In the territory. The driving force behind species change is natural selection. Presentation on the topic: Natural selection. The first position of the theory. Alkaline intestinal environment. Drought in the savannah. Intraspecific struggle for existence. The second position of the theory. Combating unfavorable environmental conditions. In reproduction. In nature there is a continuous struggle for existence. The main provisions of Charles Darwin's theory of natural selection.

“The main driving forces of evolution” - Examples of combating unfavorable environmental conditions. Driving forces of evolution. The result of disruptive selection. Examples of interspecific struggle. Examples of intraspecific struggle. Combating unfavorable environmental conditions. Forms of natural selection. The result of stabilizing selection. Provides adaptation to various groups of individuals. Forms of the struggle for existence. Interspecies struggle. The result of driving 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 natural selection at work. An example of disruptive selection. Stock of genetic variability. Driving or directed selection. The principle of natural selection.

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Lesson objectives:

• Introduce students to various forms of struggle for existence;
• To teach how to correctly identify the forms of struggle for existence;
• Convince that natural selection is the main driving force of evolution.