Quantitative Genetics and Natural Selection

These flashcards cover key concepts from the lectures on quantitative genetics and natural selection, providing questions and definitions that encapsulate the main ideas discussed in class.

What is population genetics?

The study of the distribution of alleles within populations and the mechanisms that can cause allele frequencies to change over time.

What are quantitative traits?

Traits for which phenotypes form graded series between extremes, including continuous traits, categorical traits, and dichotomous/threshold traits.

What is the primary focus of quantitative genetics?

The inheritance and evolution of quantitative traits, characterized by statistical measures of means and variances.

What is the significance of Darwin's 'On the Origin of Species'?

It introduced the ideas of common ancestry and natural selection as mechanisms of evolution.

What is natural selection?

The mechanism of evolution where differential survival and reproduction occur due to phenotypic differences.

What is blending inheritance?

A model where inherited traits are determined from a blend of parental values, which blended away favorable traits before natural selection could act on them.

Who is Gregor Mendel?

A scientist known for his work on inheritance, whose particulate inheritance model showed that traits could reappear in offspring.

What is the theory of evolution?

The idea that life on earth evolved gradually from a primitive species, with natural selection as a key mechanism.

What defines heritability in genetics?

The proportion of total phenotypic variance due to genetic variation among individuals.

What are the modes of selection?

Directionality in how selection acts: directional selection shifts the population mean, stabilizing selection decreases variance without shifting the mean, and disruptive selection increases variance.

What is the Modern Evolutionary Synthesis?

A reconciliation of Darwinian evolution with Mendelian genetics, providing a consensus on how evolution works.

How do environmental influences affect quantitative traits?

They result in phenotypic variation, which can include effects from genetic and environmental interactions.

What is Muller's ratchet?

The process by which asexual populations accumulate deleterious mutations which cannot be purged through recombination.

What are good genes in the context of sexual selection?

Traits that indicate a male is healthy and likely to pass on alleles that produce healthier offspring.

What is the significance of sexual dimorphism?

The differences in morphology, physiology, or behavior between males and females of a species.

What is intrasexual selection?

A form of selection where members of the mate-limited sex compete for access to mates.

What is intersexual selection?

A form of selection where members of the reproduction-limited sex choose which individuals to mate with.

What are the consequences of differential investment in reproduction between sexes?

They lead to differences in reproductive rates and variances in success, influencing sexual selection dynamics.

What is the concept of cryptic female choice?

The influence females have over which sperm fertilize their eggs, often occurring after mating.