AP BIO - evolution

Divergent evolution

The process where two or more related species become more dissimilar over time, often due to different environmental pressures.

Convergent evolution

The process where unrelated species develop similar traits due to adapting to similar environments or ecological niches.

Co-evolution

The process where two or more species influence each other's evolutionary trajectory through interactions such as predation, parasitism, or mutualism.

Punctuated Equilibrium

A theory in evolutionary biology that proposes that species remain relatively stable for long periods, interspersed with brief periods of rapid change.

Artificial Selection

The intentional breeding of organisms by humans for specific traits, contrasting with natural selection.

Natural Selection

The process by which organisms better adapted to their environment tend to survive and produce more offspring, leading to evolutionary change.

Fitness

The ability of an organism to survive and reproduce in its environment, often measured by the number of offspring produced.

Adaptation

A trait that enhances an organism's ability to survive and reproduce in a specific environment.

Variation in nature

Differences among individuals in a population, which can be caused by genetic differences, environmental factors, or a combination of both.

Selective pressure

An environmental factor that influences which individuals survive and reproduce, thereby affecting the evolution of a population.

Microevolution

Small-scale evolutionary changes within a population, often involving changes in allele frequencies over time.

Macroevolution

Large-scale evolutionary changes that occur over long periods, leading to the emergence of new species and higher taxonomic groups.

Homologous structures

Anatomical features in different species that share a common ancestry, indicating divergent evolution.

Analogous structures

Anatomical features in different species that serve similar functions but do not share a common ancestry, indicating convergent evolution.

Vestigial structures

Anatomical features that have lost most or all of their original function through evolution, providing evidence of an organism's evolutionary history.

Hardy-Weinberg Equilibrium

A principle stating that allele and genotype frequencies in a population will remain constant from generation to generation in the absence of evolutionary influences.

Conditions for Hardy-Weinberg Equilibrium

1) Large population size, 2) No mutations, 3) No gene flow, 4) Random mating, 5) No natural selection.

Genetic Drift

A mechanism of evolution that involves random changes in allele frequencies in a population, often having a more pronounced effect in small populations.

Gene flow

The transfer of genetic material between populations through migration, which can introduce new alleles and increase genetic diversity.

Disruptive selection

A type of natural selection that favors individuals at both extremes of a trait distribution, leading to two or more contrasting phenotypes.

Directional selection

A type of natural selection that favors one extreme phenotype over the others, causing a shift in the population's trait distribution.

Stabilizing selection

A type of natural selection that favors intermediate phenotypes and reduces variation in a trait.

Speciation

The process by which new species arise, often through mechanisms such as allopatric or sympatric speciation.

Species

A group of organisms that can interbreed and produce fertile offspring, and are reproductively isolated from other such groups.

Hybrid

An offspring resulting from the crossbreeding of two different species, often exhibiting reduced fitness or fertility.

Prezygotic barriers

Reproductive barriers that occur before fertilization, preventing mating or fertilization between species.

Postzygotic barriers

Reproductive barriers that occur after fertilization, affecting the viability or reproductive capacity of hybrid offspring.

Allopatric speciation

Speciation that occurs when populations are geographically isolated, leading to reproductive isolation and divergence.

Sympatric speciation

Speciation that occurs without geographical isolation, often through mechanisms such as polyploidy or behavioral changes.

Miller-Urey experiment

An experiment that simulated early Earth conditions to demonstrate the abiotic synthesis of organic compounds, supporting theories about the origin of life.

Early Earth

Characterized by a harsh environment with volcanic activity, a reducing atmosphere, and no free oxygen, which facilitated the formation of organic molecules.

First life

Simple prokaryotic organisms that emerged around 3.5 billion years ago, likely obtaining energy through chemosynthesis or photosynthesis.

Eukaryotic cells appearance

Eukaryotic cells are believed to have appeared around 1.8 billion years ago, with evidence supporting the endosymbiotic theory explaining their origin.