BIOL2040: Evolution Review

Flashcards created for BIOL2040 Evolution review, covering key concepts and terminology.

Descent with modification

Change in characteristics over generations.

Natural selection

Process whereby beneficial alleles increase in frequency over time due to increased survival and reproductive success.

Mutation

Random changes in DNA that can create new alleles and variation in traits.

Gene flow

The transfer of alleles or genes from one population to another.

Genetic drift

Random changes in allele frequencies in a population, often having a bigger impact in small populations.

Erasmus Darwin

Proposed that all life arose from a single living filament that was modified over time.

Jean-Baptiste Lamarck

Proposed the inheritance of acquired characteristics as a way species evolve.

Hardy-Weinberg equilibrium

A state where allele frequencies in a population remain constant in the absence of evolutionary forces.

Fitness

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

Adaptation

An inherited trait that increases an organism's fitness through natural selection.

Exaptation

A trait that evolved for one function and is co-opted for another.

Mendelian Genetics

The study of how traits are inherited through the laws established by Gregor Mendel.

Law of Segregation

Each individual has two copies of each gene, which separate during gamete formation.

Law of Independent Assortment

The inheritance of one trait typically does not influence the inheritance of another if they are on different loci.

Blending inheritance

The idea that offspring are a blend of parental traits, leading to loss of variation.

Particulate inheritance

The notion that genes are passed down as discrete units, preserving variation.

Selection differential (S)

The difference between the mean trait of selected individuals and the mean of the whole population.

Evolutionary response to selection (R)

The difference in trait means between generations due to selection.

Quantitative trait loci (QTLs)

Genomic regions that contribute to the variability of a quantitative trait.

Apomorphy

A derived trait that distinguishes a clade from other organisms.

Plesiomorphy

An ancestral trait that is shared by a group of organisms.

Synapomorphy

A shared derived trait that defines a clade.

Symplesiomorphy

A shared ancestral trait among a group of organisms.

Clade

A group of organisms that share a common ancestor.

Monophyletic

A group that includes a common ancestor and all its descendants.

Paraphyletic

A group that includes a common ancestor but not all its descendants.

Polyphyletic

A group that does not include the most recent common ancestor of its members.

Linkage disequilibrium

The non-random association of alleles at different loci, often due to their proximity on a chromosome.

Linkage equilibrium

The condition where the frequencies of alleles at different loci are independent of one another.

Cost of sex

The idea that sexual reproduction has disadvantages compared to asexual reproduction, such as producing males.

Good genes hypothesis

Suggests that females choose mates based on indicators of genetic quality.

Sensory bias

Female preferences for male traits that are exaggerated or novel can drive male trait evolution.

Reproductive isolating mechanisms

Barriers that prevent species from interbreeding, maintaining distinct species.

Allopatric speciation

Speciation that occurs due to geographic isolation.

Parapatric speciation

Speciation occurring when populations are adjacent to each other but do not mate randomly.

Sympatric speciation

Speciation that occurs without physical barriers to gene flow.

Haldane’s Rule

In hybrid offspring, the heterogametic sex (e.g., XY) tends to be at a fitness disadvantage.

Extinction vortex

Feedback loops leading to population declines where extinction risk increases.

Cladogenesis

Branching evolution leading to the formation of new species.

Anagenesis

Gradual evolution within a single lineage without branching.

Pseudoextinction

When a lineage is considered extinct but continues to exist in another form.

Phylogenetic comparative methods (PCM)

Statistical methods used to account for the evolutionary relationships among species when analyzing traits.

Heterochrony

Differences in the timing of developmental events among species leading to phenotypic differences.

Homeotic genes

Genes that regulate the development of anatomical structures in various organisms.

Deep coalescence

A process where alleles coalesce to a common ancestor earlier than the speciation event.

Out-of-Africa hypothesis

The theory that modern humans originated in Africa and spread to other parts of the world.

Multiregional hypothesis

The theory that modern humans evolved from local populations of H. erectus around the world.

Interbreeding

The process whereby different species or populations breed and exchange genetic material.

Genotype

The genetic constitution of an individual.

Phenotype

The observable characteristics of an organism influenced by its genotype and environment.