Adaption and Evolution 1/12/17

Seite 1

Terms:

Natural Selection

Adaptation

Population

Fitness

Heritability (h^2)

Phenotypic Plasticity

Evolution

Selection

Selection Coefficient (s)

Darwin = a gentleman of

distinction, naturalist

Observations while on ship…

Variability of life forms

Similarities suggested

relatedness

Logical arguments:

Heritable variation within

species

Prodigious reproductive

potential of organisms

Intense competition

Conclusions:

Concept of evolution by

natural selection

Mechanism:

Individuals with inherited

traits that increase fitness will increase in frequency in the

population relative to other competing individuals

Prereqs for Natural Selection

Phenotypic variation

Differential survival and/or

repro success associated with certain phenotypes

Individual capacity to

overproduce is limited by environmental resources

Trait heritability

Genotype + Environment +

Development = Phenotype

Selection Coefficient (s) = 1... you're dead

Mechanisms of Evolution

Finches eat small seeds

Drought eliminates small

seeds leaving only large, hard ones

Proportion of finches with

deeper, more massive bills increase

Evolution by Natural

Selection Checklist:

Phenotypic variation

Competition among individuals

Differential survival

Trait heritability