Intro to Ecology (BIO 262) Unit 1

Natural Selection

the differential survival and/or reproduction of organisms that vary in one or more characteristics.

Evolution

a change over time in the proportions of individual organisms differing genetically in one or more traits (= change in allele frequencies in a population over time)

Ecotypes

populations of a species adapted to specific environmental conditions, leading to distinct genetic traits.

Directional selection

natural selection that acts in favor of an extreme phenotype over other phenotypes in a population, pushing a population’s phenotype in one particular way. Ex: woolly mammoths: sabertooth tigers eat small ones, push population to be bigger.

Stabilizing Selection

selection that acts against extremes; selection favoring phenotypes that are intermediate in some aspect. Ex: palm trees: small trees get eaten, large trees get knocked down by wind, so average trees do best

Disruptive selection

selection favors extreme phenotypes at the cost of intermediate phenotypes. Ex: fish: small fish hide or aren’t worth eating, large fish are too fast and hard to catch, medium fish are easy to catch and get eaten. Therefore, the small and large fish are selected for.

Heritability

(h²): proportion of total phenotypic variation in a trait that can be attributed to

genetic variance

Predation

eating animals

Herbivation

eating plants

Mimicry

prey looks like a harmful/dangerous organism

Batesian mimicry

harmless mimic looks like harmful model

Mullerian mimicry

harmful mimic that looks like a harmful model

Passive defense

do nothing, and hope that a predator doesn't notice you

Cooperative defense (active defense)

when seeing a predator, prey form large groups

Active escape

prey tries to flee the predator

Kin Selection

a type of natural selection where an organism acts to help its genetic relatives survive and reproduce, even if it hurts the helper's own chances of survival

Relatedness

the average proportion of alleles that two individuals share

Group Selection

Selection for traits that benefit individuals of a group that are not necessarily related to one another

metapopulations

a group of separate local groups of the same species that live in different areas and interact when individuals move between them

Acclimation

short-term physiological adjustments to the environment

Conformer

Adjust their body temp to that of the environment

Endotherm

an animal that generates its own body heat through internal metabolic processes rather than relying on the outside environment

Ectotherm

an animal that relies on external environmental sources of heat to regulate its body temperature

Behavioral Thermoregulation

a conscious, goal-directed action an organism takes to manage its body temperature and maintain thermal

Stabilizing Selection

Disruptive selection

Directional Selection