BIOL 286 Exam 2

lectures 10-18

cooperative breeding

social system in which group members help to raise young that they did not produce, AND may delay their own reproduction (e.g. birds, insects, naked mole rat)

dialects

naked mole rates have colony specific types of sounds and chirps

cooperative breeding ecological factors

relatively stable, productive environments favor it & unpredictable environments are prone to deteriorate, less productive

home range

the portion of the habitat used on a daily or seasonal basis

territoriality

exclusive use of a part of all of the home range: requires defense and may have fitness consequences

territoriality

the size of food-resource territories increases as a function of body mass; large animals have larger territories than predicted on the basis of their energetic needs and overlap

territoriality

territory size may also be relate to sexual selection; a male that can successfully defend a larger territory may attract more females (e.g. elephant seals)

migration

physical movement from one area to another and back again; allows organisms to track resources and habitat quality; carries risks of predation and starvation

dispersal

the one-way movement of an individual from the natal area; results in gene flow if dispersers breed in new habitat; introduces mortality risk associated with movement

phylopatry

the lack of dispersal

natal dispersal

away from where born prior to reproduction; may be independent of environmental conditions, thus minimizing the probability of inbreeding

pre-saturation dispersal

occurs before resources become sparse

saturation dispersal

the dispersal to avoid the shortage of important resources such as food or nest sites

inclusive fitness

the relative ability to transfer one’s genes, or copies of them, into the next generation

direct fitness

based on personal reproductive success

indirect fitness

based on that of individuals that carry copies of one’s genes

parent-offspring

0\.5

grandparent-grandchild

0\.25

aunct/uncle-niece/nephew

0\.25

first cousins

0\.125

altruism directed toward kin

may be adaptive; altruism directed toward non-kin may not, but will depend on the social system

cooperative breeding

may result from kin selection or the improbability that an individual can leave the group and find a mate

social system

integrates a collection of behaviors that are adaptive in a specific environment

behavior

influences effective population size and potential for inbreeding

Marjory Stoneman Douglas

instrumental figure in American environmental movement; fought to protect Everglades and raise to National Park status; campaigned from Women’s suffrage

social reciprocity

the mutual exchange of good or actions for the benefit of each member in the exchange (e.g. vampire bats regurgitating blood to stop roost-mates from starving)

reproductive and social behaviors

may lead to, or maintain, differences among species

phylogeny

used as a synonym for evolutionary tree; a hypothesize diagram that shows the history of divergence and change from a single ancestral line to its descendents

principle of parsimony

choice among alternative that require fewest number or evolutionary changes; the least complex explanation to explain data

homologous characters

those that are similar in different organisms because they were derived from a common ancestor (e.g. vertebrate forelimbs - may have differences in form & function but have same arrangement of bones)

analogous characters

traits that serve a similar function but have separate evolutionary origins; result of convergent evolution (e.g. bird and bat wings)

convergent evolution

similarity between species in certain traits that is caused by similar, but evolutionarily independent, responses to common environmental problems; independent appearance of evolutionary novelties; unrelated organisms develop traits that serve the same function (e.g. cacti and euphorbs)

homoplasy

similarity in the characters found in different species NOT inherited from a common ancestor: convergent and parallel evolution

parallel evolution

similar phenotypes arise from similar developmental origins in different species (e.g. attachment organ in larval stages of blind cave fish, clawed frogs & sea squirts de to the expression of similar genes)

taxon

any group of species that we designate or name (e.g. vertebrates)

clade

a taxon that consists of all the descendants of a common ancestor

timing of divergences

shown by the position of nodes on a time or divergence axis; length of tree branches convey time

general events leading to speciation

populations become isolated from some reason; populations diverge in one or more traits; reproductive isolation; secondary contact with isolated gene pools & may not be able to successfully reproduce

secondary contact

if populations come back into contact

varied speciation rates

habitat specialization; diet specialization; changes in ploidy

allopatric

speciation among populations with discontinuous distributions

sympatric

speciation among populations with overlapping distributions

allopatric dispersal

new populations established in area and subjected to unique selective pressures

allopatric peripatric

small isolated population drifts to become reproductively isolated

allopatric vicariance

existing populations divided by physical barriers

sympatric

reproductive isolation must occur without geographic isolation; groups on their way to becoming separate species remain in contact with each other and should have the possibility of gene flow

polyploidy

changes in chromosome number (e.g. 30-70% of angiosperms)

autopolyploidy

genome duplication within a species

allopolyploidy

genome duplication associated with hybridization (mating among different) species

biological species

a group of interbreeding organisms that have an isolated gene pool

base unit of taxonomic classification

consisting of an ancestor-dependent group of populations of evolutionarily closely related similar organisms

description of the new species is required

defined what features (behavioral, anatomical, genetic) mark it out as being unique and new, must allow it to be distinguished from close relative, and details of the origins of the species type and subtypes

new species

this description and data must be published in form that is internationally accessible and archived in multiple locations

subspecies

group of phenotypically similar populations of a species inhabiting a geographic subdivision of the range of that species but differing taxonomically from other populations of that species

microsatellites

a tool for genetic analysis

microsatellites

tandemly repeated DNA motifs of various lengths (usually

microsatellites

can be amplified by polymerase chain reaction (PCR), so easy to make lots of copies of for analyses

genetic haplotypes

combinations of gene variants, usually single nucleotide polymorphisms (SNP’s), that are likely to be inherited together within the same chromosomal region

genetic haplotypes

areas are less prone to recombination than would be expected by chance

inversions

suppress recombination

coalescence

tool for developing gene trees

tree depth/time

traces alleles back to common ancestor; large populations is longer than those for smaller populations

gene trees

tool for characterizing evolutionary relationships and effective population sizes

barriers to hybridization

occur at many stages: prezygotic & postzygotic

hybridization

reproduction between individuals of different species

prezygotic mechanisms

timing of reproduction, geographic, habitat isolation, behavioral (mating displays)

temporal reproductive isolation

difference in mating time

habitat isolation

species may co-exist in the same geographic area, but are specialized on particular features/species in the habitat

habitat fragmentation

may be causing space use overlap between monkeys that would normally not come in contact

reproductive incompatibility

structural/mechanical (differences in reproductive anatomy)

structural/mechanical incompatability

differ in genitalia (e.g. female Drosphila show greater resistance and refusal to mate with hybrid or heterospecific males compared to conspecific males)

heterospecific

males of different species

gametic attraction/incompatability

inability of one species’ sperm to fertilize eggs of different species (e.g. chemical cues in eggs that only attract sperm of same species for aquatic or marine environments)

postzygotic mechanisms

parental genomes may be incompatible, hybrid inviability, hybrid sterility, hybrid inferiority/breakdown

parental genome incompatibility

may lead to reduced survival or reproduction

hybrid inviability

(occurs in finches of Galapagos) through hybridization occurs

hybrid sterility

e.g. mules produced through the mating of a donkey and horse

hybrid inferiority/breakdown

hybrids have lower fitness than either of the parental species in the population

hybridization

the cause of the isolation, must have evidence between species, must be reproductively isolated from parental species

introgression

transfer of genetic material between two species through hybridization and then backcrossing with the parental species, so there is no speciation

homoploid hybrid species

those formed without a ploidy change

homoploid hybrids

if they have higher fitness than either parental species, especially if introduced into novel habitats, can be selected for, rarer but has been documenteda

adaptive radiation

organisms that rapidly and simultaneously diversify from a common ancestor, proposed by HF Osborn

ecological opportunity

a reduction in competitors provides a chance for radiating species to use ecological niches that they were previously excluded from; reduction in predators allows the use of habitats that were previously dangerous/inaccessible

recent adaptive radiation

differentiation of a single ancestor into an array of species that inhabit a variety of environments and that differ in traits used to exploit those environments

adaptive radiation criteria

common ancestry, phenotype-environment correlation that demonstrate link between the divergent phenotypes of descendant species and their differing environments, adaptive value of trait in different environments, and rapid speciation

ecotypes

genetically distinct populations adapted to local conditions, may be on route to speciation

environmental variation driving species variation

ecotypes and phenotypic plasticity

evolution of ecotypes

existence of the genetic variation in the trait, the intensity of natural selection, geographical barriers to gene flow, likely end results of genetically isolated ecotypes

hominoids

primates that include lesser apes and great apes

hominins

species on the human branch of the hominoid tree

lesser apes

have proportionally larger brains and lack tails, but are smaller and have less sexual dimorphism

phylogeny of greater and lesser apes

diverged about 18 mya

primates

order of mammals

suborders

prosimians & anthropoids

prosimians

‘first apes’, have enlarged eyes and ears, generally nocturnal without color vision

anthropoids

‘human-like’ primates/simians, monkeys and apes

monkeys

generally have tails and more horizontal posture

apes

don’t have tails and have more upright body posture

introgression

occurrence of hybridization between two species, followed by hybrids backcrossing with their own species; allows alleles from one species to get incorporated into the gene pool of another species