EEB 390 Final Exam - Umich

Constant traits

phenotypes with fixed expression across environments (Vp=Vg, even across environments)

Reaction norm

the distribution of phenotypes for one genotype over a range of environmental conditions

Most traits are the product of an interaction between...

genes and environment

"Big Four" environmental factors

diet, temperature/day length, parasites, social environment

New view of plasticity

1) fundamental to the way organisms cope with environmental variation

2)how traits change over evolutionary time

types of plasticity

reversible vs. irreversible

adaptive vs. non-adaptive

Traditional Perspective

genes lead and phenotypes follow in the process of adaptive evolution "genes as leaders"

Alternative Perspective

phenotypic variation, even when environmentally induced, creates the conditions that result in an adaptive genetic response ('genes as followers')

Canalization

evolution of internal mechanisms that constrain plasticity to consistently produce one phenotype

Genetic assimilation

when a trait that initially appears only in response to environment becomes genetically determined

Evolvability

the capacity of a system for adaptive evolution

Asexual reproduction

production of offspring from unfertilized gametes

Sexual reproduction

joining together of genetic material from (usually) two parents to produce an offspring that has genes from each parent

Two-fold cost of sex

asexual lineages multiply twice as fast as sexual lineages because all asexual individuals can reproduce

Anisogamy

production of two different kinds of gametes

Isogamy

production of one kind of gametes

Search cost

individuals of different sexes must locate each other, which costs time and energy and risk of predation

Breaks up favorable combinations

sex (recombination) scrambles genotypes, disrupting favorable combinations; asexual reproduction preserves advantageous genotypes

Fisher-Muller Hypothesis

sexual reproduction can combine the beneficial mutations from different individuals, accelerating adaptive evolution

Muller's Ratchet

process by which the genomes of an asexual population accumulate deleterious mutations in an irreversible manner

Red Queen Hypothesis

sex helps hosts evolve fast enough to maintain their defense against parasites

Sexual selection

differential reproductive success resulting from a) competition for mates among the same sex (intrasexual) or b) attraction to the opposite sex (intersexual)

Sex role reversal

females that are larger and more brightly colored than males

Intersexual selection

attraction preference from the opposite sex

Sensory Bias

females choose males that have a characteristic that is similar in nature to a preference unrelated to reproduction

Indirect benefits

benefits that affect the genetic quality of a particular female's offspring, such as male offspring that are more desirable to females

Direct benefits

benefits that affect a particular female directly, such as food, nest sites, or protection

indicator traits (Good genes)

traits that signify overall good health and well-being of an organism, increasing its attractiveness to mates

Runaway Selection

a form of sexual selection that occurs when female mating preferences for certain male attributes create a positive feedback loop favoring both males with these attributes and females that prefer them

Intrasexual selection

due to competition between members of the same sex

Sexual dimorphism

Differences in physical characteristics between males and females of the same species (color, body size, structures)

Alternative mating strategies

divergent ways that males of the same species use to acquire mates

Sperm competition

the competitive process between spermatozoa of two or more different males to fertilize the same egg during sexual reproduction

Sexual conflict

evolution of traits that confer a fitness benefit to one sex but a fitness cost to the other

Perspective of the female

sperm competition increases fertilization rates and genetic variability of progeny

Perspective of the male

multiple mating reduces his probability of siring offspring

Game theory

a mathematical approach to studying behavior that solves for the optimal decision in strategic situations (games) where the payoff to a particular choice depends on the choices of others

Payoff

for evolutionary biology it is fitness increase. For other scenarios it can be food, profit, the good bit

Cost

for evolutionary biology, it is the fitness decrease

Cooperation

when ones actions benefit another

Conflict

when fitness interests of tow individuals differ

EES (Evolutionary Stable Strategies)

a strategy that, if adopted by a population, cannot be invaded by any alternative strategy

Reciprocal altruism

altruistic behavior can be maintained evolutionarily if individuals sequentially exchange acts of altruism

Direct fitness

fitness of a gene or individual through production of its own surviving offspring

Indirect fitness

fitness through an organism's genetic relatives

Inclusive fitness

sum of direct and indirect fitness

Siblicide

larger/older individuals kill smaller siblings

Dilution effect

change of an individual being captured by a predator decreases as group size increases

Kin selection

a form of natural selection in which an individual's fitness is influenced by the presence or actions of genetic relatives

Kin cooperation

association with genetic relatives increases either direct or indirect fitness

Kin competition

relatives directly compete for local resources and individuals gain fitness at the expense of their kin

Coefficient of relatedness

r, measures the expected proportion of shared alleles that are identical by descent

Hamilton's rule

when C < r B

C = cost to the altruistic party

r = genetic relatedness

B = fitness benefit to recipient of altuism

Eusociality

a social organization in which there is reproductive division of labor (many individuals have zero reproductive success)

Haplodiploidy

sex is determined by the number of copies of each chromosome that an individual recieves

Coevolution

reciprocal genetic change in interacting species, owing to the natural selection imposed by each on the other

Mutualistic

when effects are positive for both species

Antagonistic

when effects are negative for one species

Commensalistic

when there are no effects

Geographic Mosaic Theory

can find mutualism in some populations, but antagonistic interactions between same species in other populations

Cospeciation

speciation in one species leads to speciation in another

Antagonistic coevolution

when one species has a negative interaction

Brood parasitism

one egg-laying species benefits by having another raise its offspring

Evolutionary arms race/coevolutionary escalation

species interact antagonistically in a way that results in each species developing adaptations and counter-adaptations against each other

Character displacement

when a trait differs more between sympatric than allopatric populations of the same species

Symbiosis

long term interaction between two or more species

Mutualistic coevolution

when each species benefits from the interaction

Obligate mutualism

each partner can only survive and reproduce successfully in the presence of the other

faculative mutualism

mutualism is beneficial but not essential for the survival of each; interaction often varies over time/space

Commensalism

one benefits and the other is unaffected (or both are unaffected)

Rhizobia

bacteria that fix nitrogen after becoming established inside root nodules of legumes

Microbiome

microbial community

Vertical transmission

transmission directly from the mother to an embryo, fetus, or baby

Mimicry

a form of convergent evolution in which it is advantageous for one species to resemble another, via a shared signal receiver

Model

produces stimulus

Mimic

copies model

Predator/"Dupe"

deceived by mimic

Mullerian mimicry

multiple noxious species converge on the same warning phenotype (often color pattern)

Batesian mimicry

one toxic species has a warning phenotype which is deceitfully imitated by harmless species

Wallace's Three Laws (1867)

-models and mimics must be found in the same geographic area

-mimicry confined to a few groups (rare phenotype)

-imitators must be less abundant than models

Life history

investment in growth and reproduction that affects life span and population growth

Fecundity

the reproductive rate of an organism or population, measured by the number of gametes, seed sets, asexual propagules, etc.

Cost of reproduction

reduction of an individual's future fitness caused by reproductive activity

Semelparous

strategy in which individuals only reproduce once in their lives

Iteroparous

a strategy in which individuals reproduce more than once

Life table

a mathematical framework for converting life history trait measurements into predicted rates of population increases

r-selected species

favor genotypes with higher r (high mx, at young ages)

K-selected species

favor genotypes that function well near K (lower mx, at older ages)

"Big bang" life history

semelparous strategy favored if exponential relationship between body mass and reproductive output

Evolutionary tradeoff

advantage of a change in one character is correlated with disadvantage in other characters

Optimality theory

specifying the state of a character (or strategy) would maximize fitness (often inclusive fitness)

Lack clutch

clutch size that maximizes the number of surviving offspring

Evolutionary bet-hedging

trade-off between the mean and variance of fitness (adjust clutch size or sex ratio)

Mother hypothesis

older females have lower overall health for reproduction, so post-reproductive females contribute to the fitness of their existing children

Grandmother hypothesis

older mothers may often be grandmothers by the time of menopause and therefore able to help inclusive fitness by helping raise grandchildren

In-law hypothesis

simultaneous reproduction by successive generations of in-laws lowers survivorship of offspring

Senescence

intrinsic changes that lower survival and reproduction with age

Biological aging

gradual deterioration of functional characteristics over an organism's lifespan

mutation accumulation

accumulation of random detrimental mutations causing aging

Pleiotropy

one gene influences multiple traits