Evolution and Genetics

Natural Selection

indirect at gene level, direct at individual

individuals over reproduce but #s stay constant due to environmental limitations

environment dictating natural selection at 3 levels

genetic (developmental) structure

structural (stimuli) behavior

behavioral (selection) reproduction of genes

VP formula

VP = VG + VE + VGE

adaptation

genetically based features favored by selection

adaptive traits

traits that enhance survival of their bearer relative to others

difference between adaptations and adaptive traits

adaptations are adaptive traits but not all adaptive traits are adaptations

indirect competition

each individuals independently deals w/ the selection

direct competition

interaction among individuals IS the selection

2 ways to determine adaptive value of behaviors

cost benefit analysis and comparative approach

cost benefit analysis

cost = decreased reproduction or # alleles

benefit = increase reproductive fitness

ex: optimal quail group size

comparative

convergent and divergent species

divergent species

closely related species, but possess different behaviors in their differing environments (ex. mobbing behavior of gulls-- cliff vs. ground)

convergent species

different species in similar environments have similar behaviors (

ex. ground squirrels and ground gulls

evidence for links between genetics and behavior

twin studies, drosophilia genetics, hybridization, transgenic, artificial selection, AVP/OT in moles, BDNF, Kallman syndrome

AVP/OT in moles

extra 460 nucleotides in middle of promoter for OT and AVP receptor genes = monogamy

BDNF

mutation causes issues

kallman syndrome

small gonads, no sense of smell, sexually indifferent

gene turned on in olfactory bulb, produces anosmin

Anosmin connects olfactory axons w/ olfactory bulb, causing smell

GnRH neurons that trigger sexual development begin in nose

If no anosmin, no olfactory tracks to brain, so no GnRH released

pleiotropy

1 gene controls many traits

artificial selection

dog breeds, etc

transgenics

inserting and/or transferring a gene from one species to another; the molecular transfer of species-specific behavior

ex. Drosophila per gene, controls several “rhythms”

knockout:

fosB knockout mice and nuturing

stabilizing selection

directional selection

disruptive selection