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Evolution - Coggle Diagram
Evolution
Speciation
species concepts
biological
phylogenetic
ecological
genotypic clustering
evolutionary
Reproductive isolation
pre-mating
pre-zygotic
Total reproductive isolation
post-zygotic
hybrid sterility
can be extrinsic or intrinsic
hybrid viability
Allopatric
dispersal
vicariance
Secondary contact
species form hybrid zone
reinforcement
fitness cost from hybridizing places selection pressure which flavors pre-zygotic/mating barriers
species merge
Sympatric
strong selection
ecological selection
rapid evolution of reproductive isolation
Gene flow
asymmetric
gene flow greatest from large populations
positives
reduces effect of drift
allows spread of beneficial alleles
increase variation
negatives
counteract selection
can reduce local adaption
Polyploid selection
autopolyploidy
single species diploid
allopolyploidy
interspecific hybridization
Challenges: finding mate and avoiding gene flow with parents
Population genetics
process of natural selection
selection
variation
heritability
Evolution history
Aristotle
Linnaeus
Buffon
E.Darwin
Lamarck
Malthus
Lyell
2 more items...
Struggle for existence; influence on Darwin
inheritance of acquired traits
adaption to the environment
common descent with divergence
binomial name; nested system of species
linear and hierarchal arrangement
haploids
mean fitness stays the same or rises in the absence of mutations
evolution can occur not by natural selection
mutation
genetic drift
drift can cause significant loss of variation
founder effect
Inbreeding depression
decreased fitness from increasing homozygosity
bottleneck
recombination
pleiotropy
hitchhiking
diploids
heterozygote advantage
creates a stable equilibrium
heterozygote disadvantage
creates an unstable equilibrium
leads to fixation
allele change is slow rapid and then slows with increasing allele frequency
fixation is slower in diploids than in haploids
mutations
mutations can decrease fitness over time
mutation load
u in haploids and 2u in diploids
across multiple loci: e^-u
Fixation
probability of neutral allele fixing is its initial frequency
Time to fixation = 2N haploids or 4N diploids
Coalescence time
how long ago all alleles descended from same ancestral allele
Adaption
trait or integrated set of traits that has evolved by natural selection
ancestral trait: traits inherited that are difficult to change and are sub-optimal
interactions
competition
mutualism
entangled fates
descendants of interlocking lineages have tied fates and then cooperation is promoted
co-speciation
parallel phylogenies result from vertical transmission
mutual benefits
predation
parasitism
commensalism
selection
directional
stabilizing
disruptive
evidence for ongoing selection
variation
heritability
breeding value
how much that an individual contributes to the trait mean of its offspring against the genetic background
function of additive effects of alleles
dominance
frequency
selection
R=h^2 * S
S=reproducing trait value - prior to selection trait value
Va/Vp or slope of offspring trait against parental trait
not transferable due to changing Ve and Vg
estimates populations
indicates degree that trait is genetically based
measurable effects
Senescence: deterioration with age
senescene theory
if extrinsic damage killed old you then intrinsic damage will have evolved to kill old you too
mutation accumulation theory
late acting mutations accumulate because they are not selected against
antagonistic pleiotropy theory
mutations that act early to increase fertility act late to decrease health and vice versa
pleiotropy = genes that contribute to multiple traits
reduced by modular developement
Phenotypic value
epistasis
environment
dominance
disrupted each generation
additive effects
Phenotypic variance
Va + Vd + Vi + Ve
Arises from existing variation or new mutations
large effect mutations = rapid adaption but could be very detrimental
small affect mutations = fine tuned adaption but can be very slow
modest effect mutations = most common
Sex
Isogamy = same size egg and sperm
Anisogamy = eggs are big and costly
male biased operational sex ratio (more males in dating pool than females
males compete more than females for mate = more variance in success
intrasexual
territory
intersexual
direct benefits
immediate benefits to female = chance of more offspring
good genes, honest indicator
honest indicator = costly
chance of more fit offspring
sensory bias
relies on ecological selection
runaway
positive feedback between male trait and female preference
linkage disequilibrium
frequency dependent selection
most animals are dioecy
Fishers sex ratio
stable equilibrium at 50/50
sex disadvantages
cost of producing males
destruction of favorable gene combinations
cost of finding mate
sex advantages
negative epistasis
decrease impact of deleterious alleles
red queen
sex increase rate of adaption
reduces selective interference
mullers ratchet
negative alleles accumulate in asexual populations
without sex favorable mutations must compete with each other
sex allows combing of good alleles and removal of bad alleles
combinations only rise to fixation when nested and may let bad alleles hitch-hike
beneficial alleles fix more independently in sexual populations
can return alleles lost to drift
Macroevolution
diversification patterns
species selection
competition
variation
inheritance
sex
natural selection flavors asexuality
species selection favors sex
speciation - extinction
adaptive radiation
extraordinary diversification driven by environmental or trait change
ecological opportunity
lack of predators or competition
key innovation
sister group comparisons can provide evidence of this
Phylogeny