MCAT Biology Ch16: Evolution Kap Flashcards
evolution
process of adaptation => genetic diversity and new life forms
theory
accomplished by natural selection, mutation, genetic drift, and genetic shift
explains origins of species
ways evolution is accomplished
natural selection, mutation, genetic drift, and genetic shift
Lamarck’s Inheritance of Acquired Characteristics Theory
- concept of use and disuse
- older => newer
- organs used develop, organs not used atrophy (small size) => acquired characteristics => new, more complex species
wrong => traits are inherited, NOT ACQUIRED
use and disuse
organs used develop, organs not used atrophy
acquired characteristics
Organs used develop, organs not used atrophy => CHANGES
Darwin’s Natural Selection Theory
- organisms => offspring => few survive to reproductive maturity
- chance variations of indie in pop => inheritable => advantage => favorable
- greater favorable => reproductive age and produced offspring => inc. traits in future generations => natural selection => sep. of organisms into distinct species => fitness, directly related to genetic contribution to next generation
inheritable
chance variations of indie in pop may be this
if advantage => favorable
natural selection
greater favorable => reproductive age and produced offspring => inc. traits in future generations
this is process, mech of evolution
survival of fittest => favorable genes in gene pool, freq. inc
chance variation result from mutation and recombination
“selected” by environment => surivive to reprod. age
only method capable generating stable evolutionary change over long periods of time (thousands to millions of years) (opp to microevolution)
fitness
reproductive success of individual
neodarwinism (the modern synthesis)
accepted theory
gene changed due to mutation and recombination => favorable => pass
opp = differential reproduction => pervasive in gene pool => pop, NOT INDIE, evolve
differential reproduction
after time, traits passed by more successfully becomes pervasive in gene pool
gene pool
sum total of all genes from individuals in population at a given time
changes over time => population, NOT INDIE evolves
punctuated equilibrium
research on fossil => change in species in rapid burst
contrast to Darwin’s theory
evidence of evolution
palelontology, biogeography, comparative anatomy, comparative enbryology, and molecular bio
palelontology
radioactive dating => relating anatomies and relative abundance => fossil age => chronological succession of species
biogeography
evo not equal around globe => evo in isolation = species divergence
divergence
part of biogeo evidence
species come about from evolved in isolation
comparative anatomy
comparing similar structures => degree of evo similarity
- homologus, analogous, vestigal structures
homologus structure
even if don’t have similar appearance, shape or form => similar in structure and share common evolution origin (bat wings and human arms => forearm sim. among mammals)
analogous structures
evolved separately in each species
sim. purpose but not related origin
bird and insects => developed unique mech
vestigial structures
remnants of organ lost ancestral function
tailbone => tail for balance. human walking
comparative embryology
see sim. between embryos of diff. species => evo patterns
molecular bio
DNA can mutate => compare DNA sequence between diff. species => degree of sim.
more tax distant => amount shared dec.
indirectly comparing DNA seq => compare protein structures
genetic basis of evo
generate diff at level of genome => through:
- mutations
- random base changes in DNA sequence
- recombo, novel gen combo from sex reproduction and crossing over
hardy-weinberg equilibrium
when pop not changing => gene pool is stable => no evo
Five conditions:
- large pop
- no mutations that affect gene pool
- mating between individuals in pop is random
- no net migration of individuals into or out of pop
- genes in pop are all equally successful at reproducing
predict allelic and phenotype frequences
p + q = 1 (freq of allele in pop)
p^2 + 2pq + q^2 = 1 (freq of phenotype in pop)
gene freq constant from gen to gen if no microevolution; same as parent
x2 many alleles in pop as there are individuals