biol 150

Phylogeny

History of evolution, shows that all species are equidistant from a common ancestor with extant species at tips

Transformism

No extinction or branching of lineages

Vestigial

small and useless traits that are fully developed in another related organism

Homology

similarity between species due to shared ancestor, BINARY

Structural homology

many organisms have similar structures because of ancestor (horses and bats have same arm structure)

Molecular homology

similarity of cells and other fundamental processes intrinsic to function

Analogy

features that appear similar but evolved separately due to being widely beneficial (convergent evolution)

Eusocial

social structure of organisms, like bees

Geographic distribution of species

closer more related

natural selection

differential survival and reproduction of individuals due to phenotype fitness

Postulates of evolution

variation must exist, some elements must be heritable, more individuals will be born than survive, survival and reproduction are not random

Locus

Location of a gene on a chromosome

allele

Different forms of a gene

components of biological fitness

viability, sexual selection, fecundity

null hypothesis

disprove to provide evidence for actual hypothesis

Hardy-Weinberg assumptions

mating is random, mutations do not occur, population is large, no migrational gene flow, natural selection does not occur

codominance

both alleles expressed in hetero phenotype

complete dominance

dominant allele masks recessive

directional selection

moves one way, changes mean, decreases variance

stabilizing selection

removes extremes, focuses around mean, reduces variance

disruptive selection

reduces middle, favours extremes, increases variance, mean stays same

Positive assortative mating

choose matex that share pheno. trait, increases homozygosity at loci

Negative assortative mating

traits that are not shared, increases heterozygosity

inbreeding

effects all loci, reduced fitness, frequency of rare recessives increases

outbreeding

increases heterozygosity, not evolution

genetic drift

random changes in allele frequency bc of random gamete sampling

founder effect

Small # start new population therefore less variation and varied frequencies

bottleneck

severe pop. drop, random survival

mutation

permanent change in DNA sequence, source of all variation, even bad

migration

movement of individuals (and alleles) in and out of populations

speciation

process by which isolated populations diverge and split over time

morphological species

same lineage, similar phenotypes. some look different and can breed, phenotypic variation.

biological species

groups of actually/potentially breeding. hard to test, some organisms not sexual reproducers.

reproductive isolation

prezygotic, can't even mate. post-zygotic, can't survive/reproduce.

ecological species

same niche, resources, pressures. can have similar roles, wide range of needs.

phylogenetic species

genetic similarity and history, smallest monophyletic group. availability of genetic info.

allopatric speciation

The formation of new species in populations that are geographically isolated from one another.

sympatric speciation

The formation of new species in populations that live in the same geographic area. disruptive, PA

secondary contact

when two populations that have diverged in isolation are reunited geographically

ecology

life and organism interactions with each other and environment

law of the minimum

ecosystems are not constrained by total resources, only 1 or 2 limiting resources

biogeography

range of every species is limited by biotic and abiotic conditions

primary production

sunlight, CO2 and water into sugar and O2, areas close to poles receive less energy

primary productivity

initial biomass in system, total amount CO2 fixed by photosynthesis per area

lentic vs. lotic

standing water systems vs. flowing water systems

meromictic

super stratified, don't mix epo and hypolimnion, bottom level noxic

trophic status

PP in lake, too much eutrophic, not enough oligotrophic, meso

richness, abundance, diversity

species in a region, number of individ. in species in area, weighted number including both

upwelling zones

global wind patterns move water according to coriolis, increases productivity

antagonistic selection

two fitness components in opposition to each other

viability/morality selection

ability to survive to reproduce

sexual selection

ability to procure mate

fecundity selection

number of female gametes produced

pleiotropy

A single gene having multiple effects on an individuals phenotype, more kids reduced life

freshwater zones

litoral (shallow rooted plants), limnetic (offshore, photosynth), benthic (substrate), photic (regions thatrecieve sunlight), aphotic (no sun)

thermal zones

epilimnion (upper watm, circulates, O2), meta (mid, thermocline), hypo (cold bottom, less O in summer, more soluble but less access)

winter stratification

O2 top, nutrients bottom, 0C 4C, fish die if O2 used

spring turnover

surface warms, O2 sinks, nutrients rise 0 ->4

summer strat

O2 top, nutrient bottom, 22C 4C, low O2 bc temp

autumn turnover

cools, O2 sink, nutrient rise, 22 -> 4

dimictic

mix fall and spring, shallow dont strat in summer

cold monomictic

mix once a year

warm monomictic

mix all winter fall and spring, no ice, strat early fall late spring summer

meromictic

rarely mix

adaptation

trait increases fitness relative to others without

acclimation

change in phenotype due to environment

phenotypic plasticity

the ability of an organism to change its phenotype in response to changes in the environment, same genotype different pheno in diff enviro

reaction norm

relationship between geno, pheno, and environment

genotype-environment effect

The process by which genes influence the kind of environment that an individual experiences.

negative frequency dependent selection

rare phenotypes are favored by selection

positive frequency dependent selection

the fitness of a phenotype increases as it becomes more common

red queen hypothesis

species must adapt and evolve to reproduce and to survive against competition

coevolution

parasite and host adapt together

homeostasis

steady state of internal physical/chemical processes

conduction

molecular collision through contact (standing on one leg)

convection

liquid around object (boundary layers)

radiation

heat from sun (re-radiation)

bergmann's rule

Warm-blooded animals that live in cold areas are bigger than those that live in warm areas

allen's rule

mammals living in the cold have shorter faces and limbs than mammals living in warmer areas

water balance

equal flow of water in and out of system, residence time when water stays in system

trophic status

level in food chain, defined by different characteristics

grazing pathway

feasting on living tissue of those beneath

detrital food chain

energy passed on through decomposition pathway, less than 10% material in terrestrial ecosystems consumed through green pathway

decomposer

mineralizes dead organic material into inorganic nutrients (bacteria and fungus)

detritivore

consumes dead matter, does not mineralize back into nutrients

energy loss in trophic levels

only 10% of consumed energy is used, putting a limit on the amount of trophic levels based on the population of the lowest

bioaccumulation

100% of toxins ingested stay in the body and are passed on, increasing in tissue over lifetime. more magnified in older organisms due to magnification

homeorhesis

steady flow instead of steady state, where a dynamic system returns to specific trajectory when interrupted

resistance

ability to remain unchanged when disturbed

resilience

rate community can recover after disturbed (inverse relationship with resistance)

latitudinal gradient

going from equator to poles, resistance decreases and resilience increases, niche breadth also increases

hysteresis

dependence of state of system on its history! movement between stable states depends on previous conditions

proximate questions

how do things occur? mechanism: what stimulus were involved? ontogeny: how does it change over time?

ultimate questions

why do things occur? adaptive value: how does it increase fitness? phylogeny: what is the evolutionary history?

behaviour

stimulus response that alters relationship between organism and environment. fundamentally rooted in evolutionary paradigms

innate behaviour

inherited or inborn, inflexible, can become learned, automatic response

condition dependent behaviour

flexible in response to environment

learned behaviour

not innate or born present, change based on individual’s experiences

sexual dimorphism

phenotypic variation between sexes

parental investment

energy resources and time put into offspring. sperm is cheap. asymmetric potential cause females to invest more so they must make smarter choices