Microevolution and Natural Selection

A comprehensive set of flashcards covering key concepts related to microevolution, genetic mechanisms, and natural selection.

Hardy-Weinberg Equation

A mathematical equation used to calculate allele frequencies in a population.

Gene Pool

The total collection of alleles in a population.

Microevolution

Gradual change in allele frequencies in a population over time.

Mutation

A spontaneous change in DNA that creates new alleles.

Gene Flow

The transfer of alleles from one population to another due to migration.

Genetic Drift

A change in allele frequencies in a population due to chance events.

Bottleneck Effect

A type of genetic drift where a population's size is significantly reduced, leading to a loss of genetic diversity.

Founder Effect

A form of genetic drift that occurs when a new population is established by a small number of individuals.

Natural Selection

The process that results in the differential survival and reproduction of individuals due to differences in phenotype.

Directional Selection

A type of natural selection that favors individuals at one extreme of a trait distribution.

Stabilizing Selection

A type of natural selection that favors intermediate variants and acts against extreme phenotypes.

Disruptive Selection

A type of natural selection that favors individuals at both extremes of a trait distribution.

Allele Frequency

The relative frequency of an allele at a genetic locus in a population.

Homozygous

An organism that has two identical alleles for a trait.

Heterozygous

An organism that has two different alleles for a trait.

Phenotype

The physical expression of a genotype; the observable traits.

Genotype

The genetic constitution of an individual; the alleles that it possesses.

Fitness

The ability of an organism to survive and reproduce in its environment.

Sexual Selection

A mode of natural selection where individuals choose mates based on observable traits.

Allelic Frequencies Formula

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

Genotypic Frequencies Formula

p^2 + 2pq + q^2 = 1, used to calculate expected frequencies of genotypes.

Carriers

Individuals who carry one copy of a recessive allele but do not exhibit the trait.

Autosomal Recessive

A mode of inheritance in which two copies of a gene must be present for the trait to be expressed.

Genetic Variation

Diversity in allele frequencies among individuals within a population.

Random Mating

Mating that occurs without preference for specific genotypes.

Selection Pressure

Environmental factors that affect the survival of a phenotype.

Allele

Different forms of a gene that can exist at a specific locus.

Trait

A characteristic or feature of an organism, which can be influenced by genetics.

Predation

The preying of one organism on another.

Adaptation

The process of change by which an organism becomes better suited to its environment.

Comparative Fitness

The relative reproductive success of different genotypes.

Evolutionary Change

A change in the genetic makeup of a population over time.

Phenotypic Range

The range of observable characteristics in a population.

P-value

A measure of the probability that an observed difference could have occurred by random chance.

Soot

A black powder produced by incomplete combustion of carbon-containing materials.

Natural Selection Evidence

Observations and data that support the theory of natural selection, such as changes in moth coloration.

Adaptive Radiation

The process by which organisms diversify rapidly from an ancestral species into a wide variety of forms.

Sexual Dimorphism

Differences in physical traits between males and females of the same species.

Moral Hazard

When one party is more likely to take risks because another party bears the consequences of those risks.

Overdominance

A condition where the heterozygote has a higher fitness than either homozygote.

Endemic

Species that are native to and found only within a limited area.

Gene Frequency Hypothesis

Postulates that the frequency of alleles in a population can change due to mutations.

Phenotypic Plasticity

The ability of an organism to change its phenotype in response to changes in the environment.

Cystic Fibrosis

An autosomal recessive genetic disorder that impacts the lungs and digestive system.

Evolutionary Mechanisms

Processes that bring about changes in allele frequencies, such as natural selection and genetic drift.

Complex Traits

Traits that are influenced by multiple genes as well as environmental factors.

Population Genetics

The study of how allele frequencies in populations change over time.

Biological Species Concept

Defines species based on their ability to interbreed and produce fertile offspring.

Morphological Species Concept

Defines species based on structural features.

Ecological Niche

The role and position a species has in its environment.

Allopatric Speciation

The formation of new species in populations that are geographically isolated.

Sympatric Speciation

The formation of new species without geographic isolation.

Speciation

The evolutionary process by which populations evolve to become distinct species.

Extinction

The end of an organism or a group of organisms, usually the end of a species.

Fossil Record

The collection of preserved remains or traces of organisms from the past.

Homologous Structures

Structures in different species that are similar because of common ancestry.

Analogous Structures

Structures in different species that serve similar functions but are structurally different and do not share a common ancestry.