Flashcards BIOL 214 Chapter 20: Microevolution, Hardy-Weinberg, and Natural Selection

What is the concept of evolution?

The process through which an entity changes over time.

Who proposed the idea of natural selection?

Charles Darwin

What did Charles Darwin define evolution as?

'Descent with modification'

What is microevolution?

Changes in allele frequencies within a population over time.

What is population genetics?

The study of the properties of genes and alleles within populations.

What are the four fundamental observations of natural selection?

Resource competition, intraspecific variation, fitness differences, and heritability.

What is phenotypic variation?

Observable structural, physiological, or behavioral differences among individuals.

What are the two types of phenotypic variation?

Quantitative variation and qualitative variation.

What is quantitative variation?

Continuous traits that can be measured along a spectrum.

What is qualitative variation?

Discrete character states or distinct categories.

What influences phenotypic expression aside from genetics?

Environmental effects.

What is genetic variation?

Differences in the specific alleles of genes found within individuals in a population.

What are the sources of genetic variation?

Rearrangement of existing alleles and mutations.

What is the Hardy-Weinberg Principle?

It predicts genotype frequencies in a non-evolving population.

What are the five assumptions of Hardy-Weinberg Equilibrium?

No mutation, no gene flow, random mating, very large population size, and no selection.

What does the allele frequency equation state?

p + q = 1, where p is the frequency of the dominant allele and q is the frequency of the recessive allele.

What is the genotype frequency equation?

(p + q)^2 = 1^2, yielding p^2 + 2pq + q^2 = 1.

What does p^2 represent in genotype frequencies?

Frequency of Homozygous Dominant individuals.

What does 2pq represent in genotype frequencies?

Frequency of Heterozygous individuals.

What does q^2 represent in genotype frequencies?

Frequency of Homozygous Recessive individuals.

Who is known for the concept of gradual geological processes?

Sir Charles Lyell

What did Jean-Baptiste Lamarck propose?

That species can change over time, giving rise to new species.

What did Alfred Russel Wallace contribute to evolutionary theory?

Independently co-discovered the theory of evolution by natural selection.

What is the significance of Darwin's observations on the HMS Beagle?

He observed distinct structural adaptations in related organisms.

What example did Darwin use to illustrate variation in beak shapes?

Galápagos Finches.

What is the role of heritable traits in natural selection?

Heritable traits improving fitness become more prevalent in successive generations.

What is an example of environmental effects on phenotypic variation?

Hydrangea flower color changing based on soil pH.

What are Single-Nucleotide Polymorphisms (SNPs)?

Single base-pair site differences in DNA sequences among individuals.

What is Whole Genome Sequencing (WGS)?

Comprehensive determination of an organism's entire genomic sequence.

What are the five agents of evolutionary change?

1. Mutation, 2. Gene Flow, 3. Nonrandom Mating, 4. Genetic Drift, 5. Natural Selection

What is the mechanism of mutation in evolution?

Direct alteration of the DNA sequence.

What is the primary role of mutation in evolution?

It is the ultimate source of all genetic variation.

What does gene flow refer to in evolutionary biology?

Movement of alleles from one population to another.

Give an example of gene flow.

Physical migration of animals into a new population or drifting of gametes over distances.

What is nonrandom mating?

Mating that alters genotype frequencies without changing allele frequencies.

What is assortative mating?

Phenotypically similar individuals mate with one another.

What is the consequence of assortative mating?

Increases the proportion of homozygous individuals in the population.

What is disassortative mating?

Phenotypically dissimilar individuals mate with one another.

What is the consequence of disassortative mating?

Produces an excess of heterozygous individuals in the population.

What is genetic drift?

Random changes in allele frequencies caused by chance events.

In which populations does genetic drift play a larger role?

Small populations.

What is the founder effect?

Allele frequency shifts occurring when a small subgroup establishes a new population.

What is the bottleneck effect?

Dramatic reduction in population size due to catastrophic events, limiting the allele pool.

What is natural selection?

Differential survival and reproductive success of individuals with specific heritable traits.

What are the conditions required for evolution by natural selection?

1. Phenotypic variation, 2. Variation leads to differences in offspring survival, 3. Variation must be heritable.

What is the difference between natural selection and evolution?

Natural selection is a mechanism/process; evolution is the historical outcome of change.

Define fitness in evolutionary terms.

The relative contribution an individual makes to the gene pool of the next generation.

What are the components of fitness?

1. Survival, 2. Mating success, 3. Fecundity/Fertility.

What is sexual selection?

A specific form of natural selection directed toward securing mating opportunities.

What is intrasexual selection?

Direct competition among individuals of one sex for access to mates.

What is intersexual selection?

Selection favoring traits that attract the opposite sex.

What is parental investment?

The time, energy, and risk involved in producing and raising offspring.

What is sensory exploitation?

Evolution of male traits that exploit pre-existing sensory biases in females.

How does natural selection maintain genetic variation?

Through balancing selection, frequency-dependent selection, and environmental heterogeneity.

What are polygenic traits?

Traits influenced by multiple genes that can experience different modes of selection.

What is Hardy-Weinberg equilibrium?

A theoretical state where allele and genotype frequencies remain constant over generations.

What is the equation for allele frequencies in a population?

p + q = 1

What is the Hardy-Weinberg genotype frequency equation?

p^2 + 2pq + q^2 = 1