MECHANISMS & IMPACTS of EVOLUTION - created from Mind Map

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2. GENETIC DRIFT

Definition of evolution (Darwinism)

3. GENE FLOW

1. MUTATION

4. NON-RANDOM MATING

5. NATURAL SELECTION

Definition

Example

Impacts

Change in allele frequency by random chance

Due to tsunami, the two populations of mice (black and grey) now being dominated by only grey mice population even though one black mouse was survived during the tsunami

General

Specific

1. Big losses of genetic variation for small populations 2. Little effect in large population unless enormous spans of time are involved 3. Put the population at risk of extinction 4. Increase the genetic differentiation between two or more populations

1. Founder effect

2. Bottleneck effect

Occur when a few members of the original population started a new colony in a new place like migrating (due to separation). Eg: California Cypress (a very large population) was established from a small number of individuals

Occur when a population’s size is reduced for at least one generation due to an event such as natural disaster (due to destruction). Eg: endangered species

The change in the inherited traits of a population from generation to generation

Definition

Impacts

Example

Change in allele frequency due to the movement of genes from one population to another population

1. Increase variability within the population 2. Create new combinations of traits 3. Reduce the genetic difference between the populations

A bee carrying pollen from one flower population to another

Definition

Example

Impacts

Biochemical changes of organism’s DNA (mutation is the ultimate source of genetic variation)

Sickle cell disease (by having two mutated copies of the HBB gene in each cell, results in the disease but having only one copy provides some resistance to malaria)

1. Increase genetic variation 2. Give potential for individuals to differ 3. Harmful mutations may cause genetic disorders or cancer

Example

Impacts

Definition

1. Assortative mating

2. Disassortative mating

Deaf persons marry one another

White persons marry black persons

1. Less alleles in a population gene pool 2. Less chance for evolutionary change 3. More chance of extinction

Individuals select mates based on their characteristics

Example

Impacts

Definition

Skeletal adaptations like giraffes and lizards, peppered moth in England

1. Directional selection

2. Stabilizing selection

3. Disruptive/diversifying selection

Eliminate genetic variation over time

Decrease genetic variation within a population

Increase genetic variation within a population

The differential survival and reproduction of individuals due to differences in phenotype