evolutionary bases of behavior
Post on 22-Feb-2016
29 Views
Preview:
DESCRIPTION
TRANSCRIPT
EVOLUTIONARY BASES OF BEHAVIOR
DARWIN’S INSIGHTS Wrote On the Origin of
Species Identified natural
selection as the mechanism that controls the process of evolution
Attempted to discover why organisms developed traits that suited them for their environment
DARWIN Noticed animals vary Noted some
characteristics are heritable
Noted organisms reproduce at a pace that outdoes food supply and other resources
Therefore: traits that increase reproduction increase an organisms’ survivability
EVOLUTIONARY THEORY “Survival of the fittest” Fitness: reproductive
success of an individual organism relative to the avg reproductive success in the population
2 ways traits contribute to evolution:
1: survival advantage 2: reproductive
advantage
NATURAL SELECTION Def: heritable
characteristics that provide a survival or reproductive advantage are more likely than alternative characteristics to be passed on to subsequent generations and thus they come to be “selected” over time
CONTROVERSY Went against idea of
divine intervention in life
Implied humans are not unique and they share a common ancestry with other species
REFINEMENTS Theodore
Dobzhansky synthesized Darwin’s theories with the genetics work of Gregor Mendel
Contemporary: gene pool shaped by genetic drift, mutations, and gene flow
ADAPTATIONS Def: inherited
characteristic that increased in a population b/c it helped solve a problem of survival or reproduction during the time it emerged
Key product of evolution
INCLUSIVE FITNESS Def: the sum of an
individual’s own reproductive success plus the effects the organism has on the reproductive success of related others
Explains paradox of self-sacrifice
BEHAVIOR AS ADAPTIVE TRAITS Patterns of behavior
reflect evolutionary solutions to adaptive problems
Camouflaging, fleeing, selective reproduction
PARENTAL INVESTMENT AND MATING SYSTEMS
Parental investment: what each sex has to invest—time, energy, survival risk—to produce and nurture offspring
Most males contribute little, females contribute the most
POLYGYNY When investment is
high for females and low for males:
Polygyny: mating system in which each male seeks to mate w/ multiple females, whereas the female mates w/ only one male
Favors aggressively competitive males
POLYANDRY Def: mating system
in which each female seeks to mate with multiple males, whereas each male mates w/ only one female
Very rare
MONOGAMY Def: mating system
in which one male and one female mate exclusively (or almost) with each other
MISCONCEPTIONS ABOUT EVOLUTION 1: Evolution is only a theory---evidence to
support is substantial 2: Evolutionary analyses assume that
organisms have a motive to max reproductive fitness
3: Evolutionary analyses embrace genetic determinism
top related