Unit 8 Evolution Study Guide Flashcards

Vocabulary terms and definitions covering Evolution, Natural Selection, Mechanisms of Genetic Change, Evidence of Evolution, and Speciation based on the Unit 8 Study Guide.

Natural Selection

The process by which individuals with traits better suited to their environment survive and reproduce more, causing those traits to become more common over time.

Competition

A factor for natural selection involving the struggle for limited resources, such as having only one slice of pizza for $4$ hungry people.

Genetic Variation

A factor for natural selection where a population possesses diverse traits, such as humans having brown, blonde, black, or red hair.

Differential Reproduction

A factor for natural selection where individuals with advantageous traits survive and reproduce, carrying their traits to the next generation, such as survivors of the black plague.

Overpopulation

A factor for natural selection occurring when a population exceeds its environment's capacity, such as a classroom that can only hold $32$ people due to the number of seats.

Selective Pressure

Any environmental factor, like predators, climate, or competition, that influences which traits are beneficial for survival.

Population

A group of individuals of the same species living in the same area.

Phenotypes

The observable traits of an organism (what it looks like), influenced by both genes and the environment.

Allele

A different version of a gene, such as an allele for brown eyes versus an allele for blue eyes.

Allele Frequency

The percent that a specific gene version shows up in a population.

Mutation

A change in DNA that can create new genetic variation within a population.

Microevolution

Small-scale genetic changes in allele frequency within a population over time.

Macroevolution

Large-scale evolutionary changes that occur over long periods, such as the formation of entire new species.

Speciation

The process by which a population becomes a new species, specifically when they are no longer able to reproduce.

Gene Flow

The movement of alleles between populations when individuals migrate and interbreed with different groups.

Non-Random Mating

When individuals choose mates based on specific traits, which affects the allele frequencies in a population.

Bottleneck Effect

A sudden reduction in population size, often caused by a catastrophe, which drastically reduces genetic diversity.

Founder Effect

Reduced genetic diversity that results when a population is descended from a small number of colonizing ancestors that interbreed.

Fossil Record

Preserved remains or traces of organisms from the past that indicate the time frame in which they lived and show how species have changed.

Biogeography

The study of the distribution of species across different locations on Earth, looking at where they are located now and where they once were.

Embryology

The study of early development; looks at how a new organism develops from a fertilized egg (zygote) into a fetus, with similarities suggesting common ancestry.

Comparative Anatomy

The study of similarities and differences in the physical body structures among different species.

Homologous Structure

Body parts in different species that share a common origin but may have different functions, such as a human arm and a whale flipper.

Analogous Structure

Structures that have similar functions but evolved independently, such as the wings of birds and the wings of insects.

Vestigial Structure

A reduced or unused body part that was functional in ancestors, such as the human appendix.

DNA/Amino Acids

Molecular evidence where similarities in the sequence of genetic bases or proteins indicate relatedness between species.

Common Ancestor

An ancestral species from which multiple different species evolved.

Phylogenetic Tree

A diagram showing evolutionary relationships among species, including nodes and the appearance of new traits.

Convergent Evolution

When unrelated species evolve similar traits because they are adapted to similar environment conditions.

Reproductive Isolation

When populations can no longer interbreed and produce fertile offspring, maintaining the separation of species.

Geographic Isolation

Speciation led by physical barriers, such as the formation of a river or glacier, that separate populations.

Behavioral Isolation

Speciation resulting from differences in mating behaviors or courtship rituals, such as differing mating dances in birds.

Temporal Isolation

Speciation occurring because species reproduce at different times of the day, season, or year, such as frogs breeding in early spring versus late summer.