Question | Answer |
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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