Evolution Final

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(Fall 2013) Flashcards on Evolution Final, created by j_sunga on 21/10/2013.
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Flashcards by j_sunga, updated more than 1 year ago
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Sexual Selection advantage individuals have over others of the same sex and species solely in respect to reproduction
Direct Intrasexual competition physical combat for mates or territiories, sometimes ritualized postures
Indirect Intrasexual Competition methods (4) mate guarding, mating plugs, sperm competition, infanticide
Direct Intersexual competition choose who will provide direct benefit to self or offspring (raising, gifts, resources)
Indirect intersexual selection selection for indicators of genetic quality
"handicap principle" features that impose significant cost to survival are selected for (associated with good genes)
Lek group of males crowd together and display for females
Runaway selection females prefer traits that will make their sons preferred
Non Altruism (2) Manipulation, group behaviour
Kin selection costly to individual, benefits genetic relative
r probability homologous alleles in two individuals are identical by descent
Hamilton's Rule C<Br
Corollaries of Kin selection (2) favours prevention of exploitation, conflict between relatives when B/C = 1
Greenbeard effect Altruistic alleles favoured if signal linked to behaviour, actors can detect signal, preferentially help those with signal
Reciprocal altruism requirements Each individual interacts with same set of individuals • Many opportunities for altruism in lifetime, Individual can recognize cheaters and have good memory, Potential altruists can provide roughly equivalent benefits at equivalent costs
Naive Group selection organisms sacrifice their own fitness for the greater good
Trait group model selfish favoured at organismal level, groups with more altruists are favoured
speciation formation of new species through evolutionary mechanisms
morphospecies concept and problems based on similarity - may be defined differently, hard to differentiate
biological species concept reproductively isolated
problems with BSC difficult to demonstrate (hybrids and asexual), extinct species
phylogenetic species concept smallest monophyletic group that can be separated from others
types of pre-mating isolation barriers no chance to mate (ecological/temporal), behavioural
types of prezygotic barriers mechanical, behavioural, genetic
post zygotic extrinsic and intrinsic barriers ecological inviability, behavioural sterility - developmental inviability, genetic sterility
Steps in classical speciation (3) physical isolation, divergence, reinforcement by secondary contact
Modes of speciation (4) allopatric (other), peripatric (near), parapatric (beside), sympatric (same)
Peripatric speciation small peripheral population is isolated
parapatric speciation continuously distributed with substantial ecological differences across range
implications of small/medium/large mutations on speciation small - molecular clock, can accumulate, medium - quickly to incompatibility, large - instant to incompatibility
Wright's Adaptive Landscape Model populations pushed to local peaks, can be pushed off peaks by drift then move to possibly higher peak
Speciation by Anagensis (up), evolutionary change within one lineage, no change in # of species
speciation by cladogenesis (branch) - branching of one lineage into two or more, descendants may coexist
3 reasons for decoupling of genetic and morphological variation cryptic species, small genetic differences with major effects, very slow morphological change
patterns of branching (2) phyletic gradualism, punctuated equilibrium
Phyletic Gradualism morphological evolution is gradual, constant, involves entire population, new species arise by gradual transformation
punctuated equilibria quick transitions from one form to another, ALWAYS involves branching
reasons for stasis lack of new variant spreading (only in local population), habitat tracking
reasons speciation may not occur habitat, genetic or historical constraints
examples of one way interspecific interactions mimicry, commensalism
examples of mutualistic situations plant and pollinator, provider and protector, endosymbiosis
Situations for coevolution (2) Mutualistic, interspecific competition
Character displacement instead of becoming extinct, species diverge to specialize in different niches
Ecological Release constraints are released and expansion of resources species use (can occur by competitor disappearance)
Red Queen Effect running to stand still - escalating traits with no net advantage
reasons for arms races to stop escalation (4) Constraints, diminishing returns (too costly), predator/parasite shift to new prey/host, one or both species become extinct
cospeciation common pattern of speciation (parallel phylogenies) due to mutualism, parasitism, monophagy
Explanations for parallel phylogenies (3) true coevolution, sequential evolution, spurious correlation
geographic mosaic of coevolution interactions different in various regions of species' range
factors that increase diversity (6) changing environments, new niches, innovations, cospeciation, limited gene flow, prolonged longevity
background extinction Ongoing extinction of relatively small numbers of species, roughly balanced by speciation
Causes of background extinction can not adapt to new change: environment, predator, prey, host, pathogen, competitor
Co-extinction dependant interaction lost, species follows
Mass Extinction rapid loss of large amounts (>50%) of species diversity
possibilities following extinction survival but no recovery, survival followed by diversification
main differences of holocene extinction caused by one species (aware of it), prevetnable, over span of decades
3 major approaches to reconstructing past phenetics, cladistics, model-based methods
informative unit of cladistic reconstruction synapomorphies - shared AND derived traits
Tandem Duplication due to unequal crossing over in meiosis or by unequal sister chromatid exchange in germ-line mitosis
segmental duplication duplications of large segments through replication errors
aneuploidy duplication/loss of one or more chromosomes, not entire set
possible evolutionary fates of duplicated genes (5) loss due to selection, functional redundancy, nonfunctionalization, neofunctionalizatoin, subfunctionalization
Autopolyploidy duplication of chromosomes within a species (failure of meiosis and fertilization involving diploid gametes)
Allopolyploidy hybridization between related species followed by chromosome doubling
re-diploidization Over time, may silence or lose enough of duplicate genes to behave as diploids
consequences of whole genome duplication re-diploidization, sterility/instant speciation, new avenues of diversification
significance of paleopolyploidy in plants Suggest ALL angiosperm plants have polyploidy in ancestry
ontogeny recapitulates phylogeny Organisms pass through adult stages of ancestors during development
cis regulation regulate expression of genes downstream on same DNA strand
homeobox genes Encode proteins which bind to DNA to regulate other genes
characteristics of arthropods Bilateral symmetry, segmented body, hard exoskeleton, jointed legs, many pairs of legs
heterochromy evolutionary changes in developmental timing (ex. neoteny)
neoteny sexual maturity reached while organism still shows juvenile traits
what is a genome both genome size and genotype, not a blueprint
C-value genome size of eukaryotes, haploid nuclear DNA content
DNA constancy hypothesis all chromosome sets within a species have constant amount of DNA
C-value paradox no correlation of genome size with complexity of organisms or # of genes
transposable elements Non coding sequences that can move in genome, copy themselves
Ways to change genome size Replication slippage, Polyploidy and rediploidization
phenotypic consequences of genome size body size, SA:V (physiology), development (cell division)
Holometabolous complete metamorphosis (small genomes, below threshold level)
Evolutionary Trend observable macroevolutionary pattern in which evolution occurs in a consistent direction over a prolonged period of time
Driven vs. Passive trend direction of underlying couses, predictable vs. increased variance
causes of evolutionary trends (4) directional selection, species sorting, irreversibility of evolution, expansion of variance (directional speciation)
parallel evolution involve same, but independently occurring genetic and developmental changes among related species
convergent evolution independent evolution of similar features among distantly related lineages (usually via different genetic/developmental mechanisms)
Dollo's Law evolution of features is too historically contingent to be reversed
parsimony hypothesis of fewest # of changes
Cope's Rule lineages generally undergo an increase in body size overtime
Bergmann's Rule inverse correlation between body size and temperature within a species’ range
information theory writing detailed books about one to quantify complexity
ways of measuring adaptability taxon longevity, niche diversity, geographic range, # of individuals, biomass
Life's little joke Only unsuccessful lineages demonstrate mainline/progressive series (ex. humans)
explanation for increase in mean complexity left wall - lower limit creates skewed distribution
relative progress local improvements due to arms races and changing environments
reasons for claim humans are no longer evolving medicine, food surplus, no predators, populations mixing
reasons for acceleration of human adaptive evolution increased population size, new ecological niche, more gene flow
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