megans bio 1070 unit 2 review

What is evolution?

The process that results in changes in the proportion of heritable traits within populations from one generation to the next.

What is natural selection?

A mechanism of evolution where individuals with advantageous traits are more likely to survive and reproduce.

Define adaptation in the context of evolution.

A trait that enhances the fitness of an organism in its environment.

What does fitness refer to in evolutionary biology?

The reproductive success of an organism relative to others in the population.

What is directional selection?

A type of natural selection that favors individuals at one end of a phenotypic spectrum, causing allele frequencies to shift continuously in one direction.

What is stabilizing selection?

A type of natural selection that favors intermediate phenotypes and reduces variation around the mean trait value.

What is disruptive selection?

A type of natural selection that favors extreme phenotypes over intermediate ones, potentially leading to speciation.

Define genetic drift.

Changes in allele frequencies that occur by random chance, often having a more significant impact in small populations.

What is a genetic bottleneck?

A sharp reduction in population size due to environmental events, leading to decreased genetic variation.

What is gene flow?

The transfer of alleles from one population to another, which can increase genetic similarity between populations.

What is the Hardy-Weinberg principle?

A null model for evolution that describes the expected genotype frequencies in a population under certain assumptions.

List the assumptions of the Hardy-Weinberg principle.

1. Infinite population size, 2. No mutations, 3. No migration, 4. No natural selection, 5. Random mating.

What is kin selection?

A form of natural selection that favors altruistic behaviors that benefit relatives, enhancing their inclusive fitness.

Explain reciprocal altruism.

A behavior where individuals provide benefits to others with the expectation of future reciprocation.

What is speciation?

The evolutionary process by which new biological species arise, often through genetic isolation and divergence.

What is allopatric speciation?

Speciation that occurs when populations are geographically isolated from one another.

What is sympatric speciation?

Speciation that occurs without geographic isolation, often through reproductive barriers within the same environment.

Define mutation in the context of evolution.

Changes in DNA that can lead to new alleles, serving as the ultimate source of genetic variation.

What are the two types of genetic changes caused by mutations?

Nucleotide changes and chromosomal changes.

How do mutations impact allele frequencies?

Mutations introduce new genetic variations that can alter allele frequencies in a population over time.

What is the significance of Darwin's postulates?

They outline the conditions necessary for natural selection to occur: variation, inheritance, competition, and survival of the fittest.

What is the role of environmental factors in natural selection?

They determine which traits are advantageous, influencing the survival and reproduction of individuals.

Why are adaptations not perfect?

Adaptations are shaped by historical constraints, trade-offs, and the changing nature of environments.

What is the difference between random and non-random mating?

Random mating occurs without regard to genotype or phenotype, while non-random mating involves preferences that can influence allele frequencies.

What is the significance of studying evolutionary forces?

Understanding evolutionary forces helps explain how populations change over time and the mechanisms driving these changes.

How does genetic drift differ in small versus large populations?

Genetic drift has a more pronounced effect in small populations, leading to greater fluctuations in allele frequencies.