AP Bio Evolution

Allopartic separation

Speciation happens because a given group is separated by geographic separation by the parent group.

Sympartic separation

speciation happens even though they still live in the same area

Behavioral isolation

Some members have different mating patterns, dances, behaviors, etc

Temporal isolation

Some members of the population mate and reproduce at a different time or in a different season than the rest of the population

Geographical isolation

Part of a population is separated geographically, like a mountain or body of water

Reproductive isolation

Parts of the population can’t mate with each other anymore and produce fertile offspring

Prezygotic isolation

Prevents fertilization of the egg, these barriers happen before fertilization can even happen (like behavioral or habitat isolation)

Postzygotic isolation

Mechanism of reproductive isolation that prevents formation of viable offspring (like hybrids)

Phylogenetics

Study of peny, evolutionary hof a taxonomotic group of organisms

Node

Branching point on a phylogenetic tree, nodes and branches can be rotated without changin relationships

Root node

Common ancestor of all of them

Sister group

Two most closely related

Outgroup

Lineage falls outside the claude but is closely related to it, used to determine the root of the tree

Derived character

Distingusishes a group from their ancestors

convergent evolution

Species in similar environments tend to have similar phenotypes selected for

Stabilizing selection

favors intermediate phenotypes and acts against extreme phenotypes

intrasexual selection

individuals of the same sex compete with one another, resulting in traits such as large size and horns in males.

intersexual selection

individuals of one sex chooses a mate based on certain traits

Artificial selection

form of directional selection in which humans govern the selection process.

Directional selection

favors individuals at one extreme end of the phenotypic range

Disruptive selection

favors individuals at both extremes of the phenotypic range

Genetic Drift

Random change in the frequency of a particular allele within a population. (allele frequency), such as bottleneck and founder effect.

Founder effect:

random process that reduces genetic variation, within a small population, due to separation from the larger population, by migration or geological events

Migration/Gene flow

movement of individuals between populations causing an exchange of alleles between populations.

Introduces new genes into populations, increases genetic variation

Hardy Weinberg Equilibrium  

5 conditions

1. Large Population (no Genetic Drift)

2. Absence of migration (no Gene Flow)

3. No net mutation ( no modified genes, deleted, duplicated)

4. Random mating (no Sexual Selection)

5. Absence of selection (no Natural Selection) 

does not exist in evolving populations

Things that disrupt Hardy Weinberg Equilibrium  

Mutations, non-random mating, gene flow, genetic drift, natural selection

Biogeography

study of the geographical distribution of flora and fauna

Species tend to be more closely related to other species from the same area than to other species with the same way of life but living in different areas

Natural barriers restrict the spread of species to other favorable environments

Isolation frequently produces many of variations of species

Homology

similarity resulting from common ancestry

Homologous structure

anatomical resemblances that represent variations on a structural theme that was present in a common ancestor, serve different functions (human arm, cat leg, bat wing)

Analogous structures

structures with same functions but structurally different
(bat wing, insect wing)

Comparative embryology

Reveals additional anatomical homologies not visible in adult organisms

Vestigial organs (structures)

Useless structures that were once important

divergent evolution

process where related species accumulate differences, often due to environmental changes or geographic isolation, causing them to diverge from a common ancestor

(ex: fox and dog)