Microevolution

A set of flashcards based on the topic of microevolution, covering key concepts such as mechanisms of evolution, types of selection, and genetic variation.

What is microevolution?

changes in allele frequencies within a species over time.

What are the four mechanisms that can change allele frequencies?

1. Natural selection

2. genetic drift

3. gene flow

4. mutation.

What is natural selection?

Natural selection is the process by which individuals with traits better suited to the environment survive and reproduce more successfully.

What can mutations be classified as?

1. deleterious

2. neutral

3. beneficial.

What is genetic drift?

change in allele frequencies due to chance events, particularly in small populations.

What is the founder effect?

occurs when a small number of individuals start a new population, leading to under- or over-representation of certain traits.

What is the bottleneck effect?

The bottleneck effect happens when a population rapidly decreases in size, causing a loss of genetic diversity.

How is gene flow defined?

transfer of alleles from one population to another through migration or accidental movement.

What type of selection increases the mean phenotype?

Directional selection increases or decreases the mean phenotype.

What is stabilizing selection?

Stabilizing selection removes extreme variants and favors intermediate phenotypes.

What was the result of poaching on elephant tusk frequency?

After poaching, a significantly higher percentage of female elephants became tuskless.

What was observed in the beak size of Galapagos finches during drought?

Disruptive selection led to increased frequency of specialized bill sizes—large and small bills.

How does gene duplication affect evolution?

if gene is duplicated, the second copy can accumulate mutations freely, potentially leading to new functions.

What is horizontal gene transfer?

Horizontal gene transfer is the transfer of genes between organisms, commonly observed in bacteria. (chloroplast, mitochondria)

What aspect of evolution does adaptive evolution refer to?

Adaptive evolution results in a better fit between individuals and their environment.

What does allele frequency mean?

Allele frequency is the proportion of a specific allele among all allele copies at a given locus in a population.

why would a duplicated gene accumulate mutation more quickly thana non-duplicated gene?

A duplicated gene can accumulate mutations more quickly because it has an additional copy that can maintain its original function while the other undergoes changes, allowing for greater variation and adaptability without losing essential functions.

how do new alleles originate?

1. mutations

2. horizontal gene transfer