Final Exam

What is the definition of evolution?

A change in allele frequencies within a population over time.

What are the forces of evolutionary change?

Natural selection, mutation, gene flow, genetic drift, and non-random mating.

What is a bottleneck event?

A sharp reduction in the size of a population due to environmental events, leading to loss of genetic diversity.

What is the founder effect?

When a small group of individuals establishes a new population, limiting the genetic diversity to the genes of the founders.

What does the Hardy-Weinberg principle state?

The population’s allele frequencies remain constant unless acted on by evolutionary forces.

What are the conditions for Hardy-Weinberg equilibrium?

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

What is convergent evolution?

Unrelated species evolve similar traits due to similar environmental pressures.

What is divergent evolution?

Related species evolve different traits due to different environmental pressures.

What is allopatric speciation?

Speciation due to geographic separation.

What is peripatric speciation?

Speciation that occurs when a small group is isolated at the edge of a larger population.

What is parapatric speciation?

Speciation that occurs in adjacent populations without geographic barriers.

What is sympatric speciation?

Speciation that occurs without geographic isolation due to ecological niches or behavioral differences.

What are prezygotic barriers?

Barriers that occur before fertilization, such as behavioral isolation and temporal isolation.

What are postzygotic barriers?

Barriers that occur after fertilization, such as hybrid infertility and hybrid breakdown.

What is directional selection?

Natural selection that favors one extreme phenotype.

What is stabilizing selection?

Natural selection that favors average phenotypes.

What is diversifying (disruptive) selection?

Natural selection that favors extreme phenotypes at both ends.

What is reinforcement in hybrid zones?

The strengthening of reproductive barriers.

What does fusion in hybrid zones refer to?

The merging of two species into one.

What is stability in hybrid zones?

Continued hybridization without significant speciation.

What is a cline?

A gradual change in a trait or genetic variation across a geographic area.

What is evolutionary fitness?

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

What is intrasexual selection?

Competition among same-sex individuals for mates.

What is intersexual selection?

Mate choice based on traits preferred by the opposite sex.

What is a virus?

Infectious particles made of nucleic acid and protein.

What are viroids?

Small circular RNA that infects plants.

What are prions?

Infectious proteins that cause diseases.

What are prokaryotes?

Organisms with no nucleus, smaller, and often single-celled.

What are eukaryotes?

Organisms with a nucleus, larger, and can be single or multicellular.

What is binary fission?

Asexual reproduction method used by prokaryotes.

What is horizontal gene transfer?

Transfer of genes between organisms, such as during conjugation or transformation.

What is the role of bacteria in ecosystems?

Bacteria act as decomposers, nitrogen fixers, symbionts, and pathogens.

What is the endosymbiotic theory?

Theory that mitochondria and chloroplasts originated from free-living bacteria.

How are protists evolutionarily related to other groups?

Some protists are more closely related to plants, animals, or fungi.

How are fungi evolutionarily related to other groups?

Fungi are more closely related to animals than to plants.

What are the characteristics of fungi?

Cell walls made of chitin, heterotrophic, and reproduction via spores.

What challenges do plants face on land?

Desiccation, gravity, reproduction, and nutrient acquisition.

What adaptations do plants have for survival on land?

Cuticle, vascular tissue, roots, seeds, and flowers.

What are nonvascular plants?

Plants without vascular tissue that rely on diffusion (e.g., mosses).

What are seedless vascular plants?

Plants with vascular tissue but no seeds (e.g., ferns).

What are seed plants?

Plants that have vascular tissue and seeds (e.g., gymnosperms and angiosperms).

What are progymnosperms?

Early seedless vascular plants.

What are gymnosperms?

Seed plants without flowers (e.g., conifers).

What are angiosperms?

Flowering plants with seeds enclosed in fruit.

What is water potential in plants?

Determines the direction of water movement.

What is transpiration?

Evaporation of water from leaves driving water uptake from roots.

What does stomatal regulation control?

Water loss and gas exchange in plants.

What are the features of the animal kingdom?

Multicellular, heterotrophic, lack cell walls, and capable of movement.

What are Hox genes?

Genes that regulate body plan development and differentiation in animals.

How did jaws evolve in vertebrates?

Jaws evolved from gill arches, allowing access to new food sources.

What is bioenergetics in relation to body size?

Larger animals require more energy but are more efficient per unit body mass.

What is thermoregulation?

The process of maintaining body temperature.

What are endotherms?

Organisms that generate their own heat (e.g., mammals).

What are ectotherms?

Organisms that rely on external heat sources (e.g., reptiles).

What are survivorship curves?

Graphs that represent mortality rates in populations.

What does Type I survivorship curve indicate?

Low mortality in early life and high mortality in later life (e.g., humans).

What does Type II survivorship curve indicate?

Constant mortality rate throughout life (e.g., birds).

What does Type III survivorship curve indicate?

High mortality in early life and lower mortality in later life (e.g., fish).

What is an endemic species?

A species found only in one specific location.

What is a keystone species?

A species that has a disproportionate effect on its ecosystem.

What is an invasive species?

A non-native species that disrupts ecosystems.

How are Archaea and Eukarya related evolutionarily?

Archaea and Eukarya are more closely related to each other than to bacteria.

What is a haplontic life cycle?

A life cycle where the haploid stage dominates.

What is a diplontic life cycle?

A life cycle where the diploid stage dominates.

What is a haplodiplontic life cycle?

A life cycle with alternation of generations between haploid and diploid stages.