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Definition
| mechanism responsible for evolution of characteristics that directly increase mating success; often leads to sexual dimorphism |
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Definition
| evolution of characteristics that increase competitive abilities between members of the same sex for access to mates. e.g. increased body size/strength, special weapons to win intrasexual contests |
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Definition
| evolution of behavioral, morphological, and physiological traits that increase competitive ability after mating has begun or occurred often between ejacuates of males for fertilization of eggs e.g. copulatory organs and plugs, seminal fluid volume, mate-guarding |
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| Sperm competition in C. elegans and redback spiders |
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Definition
| C.elegans utilize copulary plug polymorphism and redback spider males commit suicede because the longer the male mates with the female the more eggs it fertilizes but of course this increases its chance of getting eaten but also increases the amount of offspring it leaves behind |
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| evolution of characteristics used to attract and/or continue to convince mates e.g. behavioral displays, increased body size, bright colors, or special structures |
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| post-copulatory ability of female to choose males sperm over anothers, especially important in species with multiple mating females or forced copulations, enhanced by female sperm storage |
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| BTW: adaptiveness of homosexual rape in worms and bugs? |
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Definition
they insert copulatory plugs into a worm/bug that they rape
sometimes sperm gets incorporated and the raped male also releases the others sperm |
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Term
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Definition
1. good resources
2. good genes
3. pre-existing bias hypothesis
4. runaway sexual selection |
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Definition
access to feeding/birthing areas etc.
gifts |
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Definition
trait signals something about mate quality
i.e. parasite mediated sexual selection, handicap hypothesis |
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| parasite-mediated sexual selection |
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Definition
| healthy mate hypothesis=Hamilton and Zuk hypothesis: individuals w/ stronger expression of traits are healthier/have fewer parasites |
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Definition
| success despite handicap indicates high mate quality i.e. long peacock tail |
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| pre-existing bias hypothesis |
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Definition
| states that female preference existed before the evolution of the trait, perhaps due to some pre-existing "sensory bias" not because the trait had a value as a signal of mate quality |
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Definition
| the trait may or may not originally have provided a selective advantage, but once female preference evolved, the trait continues to evolve to a greater and greater extent, even if it became a disadvantage |
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| mechanism for evolution of characteristics that increase an individuals genetic contribution to the next generation by enhancing close relatives reproduction rather than its own reproductive fitness examples: social insects, alarm calls, helpers @ nest |
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Definition
| an individuals genetic contribution that includes both its own reproduction plus its contribution to its relatives reproduction |
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| benefit others at the risk of the individual, often explained by kin selection |
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| not all kin selected traits are altruistic |
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Definition
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evolution of cooperation has occurred largely through kin selection
Alturism is not necessarily kin selected |
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Definition
females: diploid
males haploid |
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| Haplodiploidy ( the evolution of paper wasp nest care) |
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Definition
female[2n]--->egg[n]--->male[n]
female[2n]--->egg[n] + sperm[n]--->female
in spring: daughters produced help mom raise sisters
Summer: sons produced and daughters leave to establish their own nests
sisters: share 3/4 genes
offspring: share 1/2 genes
brother: share 1/4 genes |
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Term
| Characteristics of Eusocial animals |
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Definition
1.single reproducing queen
2.overlapping generations
3.cooperative care of young
4. nest defense
include: social insects, naked mole rat, snapping shrimp |
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Term
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Definition
| random changes in gene frequencies in a population or: "genetic changes in a population due to random variations in fecundity, mortality, and inheritance of gene copies through male and female genes |
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Term
| How can changes be "random" |
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Definition
a. during fertilization, alleles are combined by chance therefore in small populations whole alleles could be lost by chance
b. by chance mortality rate for individuals possessing a particular trait may be different than for individuals possessing an alternative trait in array unrelated to the trait |
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Term
genetic drift involves random shifts in gene frequency, not adaptive change after random events
inlarge populations, genetic drift changes frequencies very slowly and generally impacts only those traits that are selectively neutral |
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Definition
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Term
in small populations, genetic drift can and will act swiftly causing changes in allele frequency and can even reduce the frequencies of selectively advantageous alleles in a population
genetic drift will reduce genetic variability in a population by eliminating alleles in a population |
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Definition
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| GD: example evolutionary loss of mammalian protein |
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Definition
| pigs have lost a certain gene that would evolutionarily keep them warm |
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| GD example: florida panther |
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Definition
population had: low genetic diversity, poor sperm quality, low testosterone, low fecundity, heart defects, high parasite loads
GD was an issue because the population was so small advantageous traits were lost and the population was in trouble, alleles from other panthers were incorporated to attempt to bring the population back up |
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Term
| GD example: loss of eye function in cave fish |
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Definition
| GD could have influenced the loss of the appendage only if it was a random event where no fish transferred the gene for creating eyes to their offspring, it may be advantageous but that is independent of genetic drift |
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Term
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Definition
an increase in the # of chromosomes beyond the typical [2n]
can occur following non-disjunction during mitosis/meiosis
can form new polyploidy species |
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Definition
| occurs among parents from the same species forming a new polyploidy species arising from a single species, 2n gametes produced by both |
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Term
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Definition
occurs via the production of polyploidy hybrids;most common method of polyploidy
non-polyploidy hybrids are usually incapable of reproducing, because they only have one copy of each chromosome making meiosis impossible
polyploidy hybrids have two copies of each chromosome and therefore through meiosis can form gametes but they must mate with a simile 4n individual |
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Term
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Definition
1.Flowering plant species may have arisen through allopolyploidy
a.york grounded senecio eboracins=polyploid hybrid of two sececio species
b. tragopogan: polyploidy weeds in western US same species has evolved several times |
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Definition
| immigration of new individuals into a population causing allele frequencies to change in a population |
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Term
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Definition
| cuban anoles: anoles in northern florida are from many different places in the Caribbean leading to the massive amount of gene diversity in that area |
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Definition
| the capacity of a phenotype to respond to environment variation or the ability of a given genotype to express different phenotypes depending on environmental conditions |
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| testing for phenotypic plasticity |
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Definition
1. reciprocal transplant experiments
2. common garden experiments |
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| Phenotypic plasticity examples |
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Definition
1. cladoceran have helmets and spines when they are in a habitat where predators are present and they are not there if they develop in an area without predators
2.tiger snake head size differs depending on whether they develop on the island or the mainland and the study showed that the island snakes had a much more plastic phenotype probably because their environment is more variable |
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Term
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Definition
independent evolution of similar form or function in different organisms
generally occurs through natural selection in response to similar selective pressures
often occurs in unrelated organisms that live in similar environments |
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| convergent evolution examples |
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Definition
1. desert plants: succulent tissues, spines, stem photosynthesis
2.Marsupials in australia are very similar to placentals elsewhere
3.yetis: are closely related to undulates but have through convergent evolution evolved characteristics of primates |
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Term
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Definition
rapid diversification of species descended from a recent common ancestor
generally occurs through natural selection as new species evolve to invade unfilled niches
often occurs in species poor environments such as islands |
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| Adaptive radiation examples |
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Definition
1. galapagos finches
2. cichlid fishes in lake malawi |
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Term
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Definition
1.biological species concept
2.there are major exceptions to/problems w/ the biological species concept |
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| biological species concept |
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Definition
groups of actually or potentially interbreeding individuals from natural populations that are reproductively isolated from other such groups
implies that speciation involves the evolution of reproductive isolating mechanisms
isolating mechanisms can be pre/post zygotic |
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| exceptions/problems w/ the biological species concept |
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Definition
not all organisms fit that definition
it is a generally good conceptual definition but not a good practical definition |
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Term
| orchids and prezygotic isolating mechanisms |
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Definition
| many orchid species are isolated by seasonal reproduction |
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Term
| mules and post-zygotic isolating mechanisms |
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Definition
| a horse and a donkey can make a mule but a mule can not reproduce so this is a post-zygotic isolating mechanism |
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Term
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Definition
-lots of plants make hybrid offspring that can reproduce
-90% of brazilian hawksbill sea turtles have an ancestor that was not a hawksbill |
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| unisexual species and species definition |
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Definition
| all-femal species, therefore they do not mate or interbreed even if they use another male species to stimulate reproduction |
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Term
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Definition
| evolutionary diversification |
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Term
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Definition
| formation of two or more species from a common ancestor through one of two mechanisms 1. allopatric speciation 2. sympatric speciation |
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Definition
| resulting from divergence of two or more populations following geographic isolation |
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Definition
| resulting from divergence of two or more populations without being isolated geographically |
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Term
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Definition
1.marine geminate species on either side of central america; allopatric speciation
2.polyploidy in flowering plants; sympatric speciation
3. cichlid fishes in lake victoria, several hundred fish species, a monophyletic group; sympatric speciation |
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Term
| Earth's surface temperature |
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Definition
1.latitudinal effects
2.altitudinal effects
3.seasonal effects |
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Term
| latitudinal effects on surface temperature |
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Definition
| heating increases toward the equator on annual basis due to the angle of the sun's rays. there are three latitudinal zones tropics, temperate, frigid |
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| altitudinal effects on surface temp |
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Definition
| temperature decreases 1C/100m in dry air and .6C/100m in condensing air |
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Term
| seasonal effects on surface temp |
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Definition
created by 1.earths tilt 2. earths revolution around the sun 3. changing angle of suns rays
during summer/winter solstice the suns rays are directly on the tropic of cancer/capricorn
during fall/winter equinox the suns rays are directly on the equator |
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