EEB 2245W: EXAM 2
75 Cards in this Set
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sexual selection
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selection for mating success rather than for viability and fitness
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secondary sexual characters
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the burdensome and costly features that allow a male to have an advantage over other males in competition for mates;
theory of sexual selection
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intrasexual competition
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members of one sex--usually males--compete with each other for access to the opposite sex
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intersexual competition
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members of one sex--usually females--exhibit preference when selecting their mates
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sexual dimorphism
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distinct differences in males and females to promote attraction of one sex by the other
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Sex reversed Role Species
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reproductive potential of females is not restricted by food resources but by males, in this case the females are larger than the males and compete with each to secure males
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male-male contests (3)
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A) Combat: larger, strength, weaponry
B) Displays: bright colors/markings, posturing, acoustic signaling
C) Territoriality
(intrasexual selection; precopulatory)
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mate guarding (paternity assurance)
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postcopulatory male-male contest;
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sperm competition
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last one in, size, amount matter
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direct benefits
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(intersexual selection) male provides a direct benefit to the female or her offspring, such that selection favors females that recognize males that are superior providers via some correlated character:
nutrition, superior territory, freedom from disease, parental care
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genetic covariance (genetically correlated)
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any increase in the frequency of the male trait is accompanied by an increase in the frequency of the female trait through hitchhiking
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Runaway Sexual Selection
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Sexual selection may result in exaggerated traits; example: the long-tailed widowbird experiment
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indirect benefits
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indirect benefits
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sexy son
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sons of females who choose males with exaggerated traits will have improved mating success because they inherit the trait that made their father attractive to their mother
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genetic quality
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"good genes" hypothesis--the preferred male trait indicates high fitness, which is inherited by the offspring of females who choose such males
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levels of selection
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multilevel selection theory; hierarchal levels of decay
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intragenomic conflict
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selection at the level of the gene (allele) if the fitness of a particular sequence is partially independent of the fate of other sequences in the same genome
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segregation distorter alleles
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strongly linked system of a distorter locus and a recognition locus
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relatedness
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all cells start out related to each other and to the organism as a whole by r=1 (=100%)
the coefficient of relatedness (r) between two individuals represents the percentage of genes that those two individuals share by common descent
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Weismannist organisms
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somatic cell line is independent of germ cell line; somatic cell lines die when organisms die
(like humans)
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group selection
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adaptations are for the benefit of the social group, population, or species
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group adaptation
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a property of a group of organisms that benefits the survival and reproduction of the group as a whole, but not the organism as an individual
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infection model
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given selfish (S) vs. altruist (A) alleles, groups with mainly altruists will go extinct at a lower rate; individual selection HAS to favor selfish individuals --> with one successful immigrant during the lifetime of the group, the selfish allele (S) will go to fixation
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kin selection
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altruistic behavior in individuals toward very close relatives -- helping your relatives to reproduce helps your own genes increase in the next generation
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inclusive fitness
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an extended phenotype
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trait-group selection
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unrelated groups with certain individual traits, e.g., altruism, out-reproduce those without those traits because of differential group-level reproductive success
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species selection
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another type of group selection that reduces conflict between levels
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altruistic trait
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a trait (or an act) that confers a benefit on someone else at a cost to the actor
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cooperation
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a basic ingredient of social interactions, social behavior, and societies
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kin group
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a very special type of group--one that contains closely related individuals (high r values)
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Hamilton's Rule
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an altruistic gene enjoys a NET benefit when the benefit to the recipient weighted by the degree of relationship to the recipient is greater than the cost suffered by the altruist
Br > C or Br - C > 0
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true sociality
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female produces offspring, and lives long enough to reproduce with those offspring
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haplodiploidy
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females are diploid (2N), males are haploid (N), developing from unfertilized eggs
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eusociality
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showing an advanced level of social organization, in which a single female or caste produces the offspring and non-reproductive individuals cooperate in caring for the young
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macroevolution
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formation of new species
rise and fall of whole lineages
origin of evolutionary novelities
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speciation
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the irreversible separation of one population into two
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clustering algorithms
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things in the same group are put together
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folk taxonomy
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kalam of Papua New Guinea + Tribes of Arfak Mtns of New Guinea --> suggests that biological similarities are very comparable
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perceptual cluster statistic
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not very likely, genes don't flow freely between pools so gene don't get tainted, co-adapted keeps it clean
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perceptual cluster statistic
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not very likely, genes don't flow freely between pools so genes don't get tainted, co-adaptation keeps it clean
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nominalist (nihilist)
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no larger units of classification above the individual
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prospective concepts
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based on process; necessarily horizontal/instantaneous
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retrospective concepts
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based on pattern; these can be applied vertically as well
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morphological species concept
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a group of individuals whose members show consistent morphological differences with respect to other such groups
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reproductive isolation
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a group of individuals whose members are reproductively isolated from all other groups, under natural conditions
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recognition species concept
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each species is unified by a shared mate recognition systems
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chronospecies
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a group of one or more species derived from a sequential development pattern which involves continual and uniform changes from an extinct ancestral form on an evolutionary scale
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ecological isolation
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environments of some animals do not overlap and do not provide reproduction likelihood, e.g. lions and tigers
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behavioral isolation
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premating RIMS due to courtship behavior
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postzygotic "intrinsic" isolating mechanisms
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hybrid incompatibilities; incapable of reproducing because hybrid doesn't work with original
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ecological species concept
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all lineage which occupies an adpative zone different from that of any other lineage in its range and which evolves separately from all lineages outside its range
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phylogenetic species concept
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smallest diagnosably distinct cluster of individual organisms within which there is a parental pattern of ancestry and descent--i.e. it is the smallest monophyletic group of common ancestry;
a species is the smallest aggregate population or lineage which can be united by synapomorphic ch…
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monophylogenetic groups
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smallest aggregate population unique specialization
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cladistic species concept
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species are unbranched segments or lineages in a phylogeny; Internodal or Hennigian species concept
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Genealogical species concept
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an exclusive group of organisms, where an exclusive group is one whose members are all more closely related to one another than to any organism outside the group
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cohesion species concept
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most inclusive group of organisms having the potential for genetic exchangeability (gene flow) and demographic exchangeability (genetic drift and natural selection)
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geographic speciation
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widespread; exists in all species; different organisms because of different geographic locations
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polymorphisms
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adapted to their own environment but same species
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clinal variation
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as cline changes, the organism adapts to its environment but same species
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mimicry complexes
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mimic another species in order to achieve better success
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Bergmann's Rule
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as latitude changes, body size changes; coldest parts of NA, largest ___ are found
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Allen's Rule
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limb length shortens as latitude goes North
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gloger's rule
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lighter pigmentation as go farther north; greater protection from the sun
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Ring species
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clinal variation and circular hybridization in seagulls;
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mosaic variation
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sympatric presence of the population it mimics
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allopatric speciation
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formation of a new species as a result of evolutionary changes following a period of geographical isolation
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dispersal allopatric speciation
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members of population move across a barrier
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vicariance allopatric speciation
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members of population are split by a barrier, none move
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Dobzhansky-Muller 2-locus Model
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1) ancestral AABB
2) barrier causes: AaBB, AABb
3) speciation occurs--> aaBB, AAbb
4) postzygotic isolation: AaBb (hybrid) --> sterile or inviable
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Dumbell model of allopatric speciation
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divides into two equal halves, usually occurs when a variant occurs, e.g. isthmus of panama
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vicariance
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geographic separation of a population, typically by a physical barrier such as a mtn. range or a river
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peripatric speciation
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founder effect speciation
rapid genetic change in peripheral populations
small populations are founded by few individual
no gene flow in parental population
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founder-flush model
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1. population bottleneck, 2. fixation of unusual gene combinations **, 3. population flush occurs, 4. population released from stabilizing selection, 5. co-adapted gene complexes are destabilized, 6. recombinants of normally low fitness increase in frequency, 7. population crashes again (…
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hybrid zones
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an area of contact between two noticeably different populations, in which hybridization takes place
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introgression
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when one allele comes into another; generally occurs when there is a neutral allele
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EEB 2245W: EXAM 2