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Evolution
UCSC Kathleen Kay
33
Biology
Undergraduate 4
03/15/2011

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Term
Good Gene Hypothesis
Definition
Male characters evolve to act as honest signals of genetic quality. Thus, Females benefit from selecting high quality males as mates
Term
Sensory bias
Definition
Male evolve to exploit pre-existing female preference. Females don't benefit from selecting these males w/ traits
Term
sexual dimorphism
Definition
Any consisten difference between males and females of a species
Term
Sexual selection
Definition
differential reproductive success due to difference in ability to attract mates
Term
Kin selection
Definition
Refers to the "indirect" component of fitness. This indirect component represents the gain in fitness made possible by an individual's altruistic act
Term
Coefficient of relatedness
Definition
the probability that homologous alleles present in different individuals are identical by descent
Term
inclusive fitness
Definition
total reproductive success of an individual, including reproduction by the individual and also reproduction by related kin
Term
direct fitness
Definition
fitness resulting from personal reproduction
Term
eusocialty
Definition
a system in which one completely foregoes reproduction. system involving overlap in generations, cooperative care of young, and non-reproductive individuals
Term
Kin Selection
Definition
Natural selection that favors the spread of alleles that increase reproduction by related individuals
Term
Two reasons why there is not an even sex ratio
Definition
1. local mate competition; occurs when a small group of related individuals are mating
2. Condition dependent sex allocation; occurs when maternal investment is high and fitter mothers produce more fit offspring
Term
systems of sex determination
Definition
heterogametic chromosomes
haplodiploidy
temperature dependent sex determination
environmentally- determined sex determination
hormone signaling
pheromones signaling
Term
explain when promiscuity would be favored by natural selection over monogamy
Definition
If two parents are not required for parental care, if mates are easy to find, or if fitness increases with the number of mates
Term
under what conditions do we expect self-fertilization in plants to evolve?
Definition
Growing season is short, mates are scarce, few pollinators around
Term
Lack's hypothesis
Definition
Selection will favor clutch size that produces largest number of surviving offspring, and there is a trade off; individual survival declines with increasing clutch size
Term
Assumptions of lack's hypothesis
Definition
1. no trade-offs between reproductive efforts across years
2. clutch size only affects viability
3. no year-to-year variation in optimal clutch size
Term
Evolutionary theory of aging
Definition
The evolutionary theory of aging posits that aging and death are attributable to inability of natural selection to prevent cell and tissue damage from occurring later in life (after peak reproductive period)
Term
Coincidental Evolution Hypothesis
Definition
the CE hypothesis predicts that the virulence of a certain pathogen is not due to any long-term coevolution between it and humans. Instead, the virulence is determined by the natural enemies of the pathogen in its native environment
Term
Trade-off hypothesis
Definition
the level of virulence is shaped by long-term coevolution to represent a balance between the harm done to the host and the reproductive rate of the pathogen in the host
Term
Example of lateral gene transfer; long time ago, and recent
Definition
long time: endosymbiosis of mitochondria or chloroplast
Recent: transfer of antibiotic resistance among bacteria
Term
Reasons why estimates of species number on earth is so variable
Definition
groups of organisms are understudied
locations / ecosystems/ environments understudied
Discover of cryptic species
Term
Dispersal and vicariance
Definition
Dispersal is when individuals leave and area and physically move to a new habitat and colonize it, forming new pops.
vicariance is when an existing pop is fragmented into 2 or more isolated pops
Term
What is a ribosome
Definition
An RNA molecule capable of catalyzing a chemical reaction similar to enzymes
Term
2 findings that suggest prokaryotes evolved 3.5 and 4.0 billion years ago
Definition
fossil stromatolites date to 3.5 bya
2. carbon isotope data with higher 12c to c13 ratio in organic deposits 3.8 bya
Term
why are neither proteins nor DNA considered likely to have been the first life forms
Definition
Proteins are unable to self-replicate, and DNA is unable to catalyze reactions.
Term
Punctuated equilibrium and phyletic gradualism
Definition
-Punctuated equilibrium posits that periods of rapid morphological change are accompanied by periods of rapid speciation and that once new species appear they exhibit stasis
- Phyletic gradualism does not require speciation for morphological divergence to occur and does not predict stasis
Term
Factors that contributed to Cambrian explosion
Definition
- increase in oxygen content of seawater
- origin of hard parts
- evolution of eyes
- diversification of homeotic genes
Term
What are homeotic genes?
Definition
- key regulatory genes that control development by specifying "positional information" in the multicellular embryo. Different genes active in different embryonic locations causing the activation of different genes creating different structures
Term
evidence of Meteorite impact for cause of K-T mass extinction
Definition
Presence of iridium. rare on earth, common in meteorites
Term
In the hominid fossil record, Homo habilis is believed to have evolved from
Definition
Australopithecus africanus
Term
Which of these traits is NOT a synapomorphy of all apes as compared to Old World monkeys
Definition
Color vision
Term
According to mitochondrial DNA data, modern humans evolved in Africa about 
Definition
150,000 years ago.
Term
Describe a feature of the hominid fossil record over the past 5 million years.
Definition
Evolution was largely continuous, gradual; there were no sudden changes in morphologies
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