evolutionary ecology exam 1

cases of genetic drift

-founder effect -bottleneck -

stablizing selection

Selection against extreme values, large or small, in a continuous trait - very common ex: birth weight of humans ex: clutch size of robin eggs- 4 eggs, anymore or anyless result in eggs with nonviable offspring or malnorished offspring

why study ecology?

We are a part of Nature and must understand how it works so that it keeps on functioning properly. application include: conservation of biodiversity and nat. systems -human impact of human disturbance understanding benefits of nat. systems

ecosytem

all the living and nonliving things in an area

mate choice

choice by one sex of the opposite sex

multiple niche polymorphism

different traits are better in different parts of the habitat ex: snails have polymorphism via color and pattern -bird predation via visibility of snails -coloration more or less beneficial depending on environment

secondary sexual trials

ex: boobs and beards -anthers in deers -limited to one sex, but not necessary for gamete transfer

sexual conflict

female and male most often dont align with each other -sex manipulates the others in ways that benefit its own reproductive success but reduce reproductive sucess of its mates ex: sensory exploitation, harassment, traumatic insemination, chemical manipulation, female sexual cannibalism

evolution mechanism: sexy sons (daughters)

traits preferred: heritable attractiveness adaptive value: attractive sons (daughter) not more offspring (either one sex but not both)

spermplugs

"mating sign" in honey bee, leave reproductive structure inside female -> hinders second mating

prediction 2 evidence

-closely related species often live in the same geographical area -fossils resemble living species in the same area -homologous traits 1)structural (morphological) ex: arm/wing./leg/fin modified over time 2)developmental (embryonic) - fish bird reptile human embryos 3) genetics (gene structure, genetic code, genetic machinery)- all organisms use same nucleotide and genetic engineering

Reproduction Cost

-females- major investment in producing offspring and taking care of offspring (limited by resources) -males- need to get mates -sometimes reversed: example: seahorse males major parental role, so do penguins sperm = cheap eggs= expensive

Evidence of Natural Selection

-heritable variations exist in natural populations -convergent evolution: placental vs marsupial mole -artificial selection- ex: selective breeding (dogs) variation already happened outside naturally and we made use of the variation -selection in nature (change in environment leads to change in selection) ex; darwins finches and industrial moths

parameters that affect genetic drift

-low population size --> speeds up rate of fixation or loss of allele, losing gen variation which is needed for natural selection -initial allele frequency matter--> rare alleles tend to be lost -time--> effect accumulate over time even in large populations (they lose genetic variation over time)

prediction 1 evidence

-many species have gone extinct -transitional forms show change through time (documentation of change) -vestigial traits are common ex; hipbone of whale, appendix in humans

distribution of bloody type B

-no B allele in N. and S. america and austrailia -migrational barrier associated with loss of B blood type allele

what ecology is not?

-not evironmentalism (this is more political goal for preservation) -not environmental science (more of an applied discipline of ecology)

evolution

-process by which organisms adapt/change overtime, across generations a) characteristics of species can be modified from generation to generation by natural selection b)species are related by common ancestry - theory of decent with modification

consequences of genetic drift

-reduces genetic variation within a population -deleterious or neutral alleles may increase or decrease

evolution related topics

-sex -food -death ask questions about why! -why have genders? who to mate with? -what to eat? how much to eat? why? -how to grow? when to reproduce? why do we die?

mechanisms of sexual selection S.S.

1) intrasexual competition (e.g. male-male competition) --> same sex individuals sort out mating opportunities among themselves ex: elk anthers 2)mate choice: choice by one sex of opposite sex based on attractive features

darwin's 4 postulates for evolution by nat. sel

1) variation 2) heredity 3)some survive and reproduce more than others (differential reproduction) 4)non-random survival and reproduction success 3+4 -> competition for existence

Evolutionarily Stable Strategy (ESS)

A phenotype such that, if almost all individuals in a population have that phenotype, no alternative phenotype can invade the population or replace it.

Batesian mimicry

A type of mimicry in which a harmless species looks like a species that is poisonous or otherwise harmful to predators. ex: butterflies that look awhile, one is tasteful while other is deadly to birds

heterozygote advantage

Aa>> AA or aa -carrier is protected, shows little effect of diease ex: malaria, Aa protected against malaria and shows little signs of sickle cell while AA is lethal to malaria exposure and aa is lethal to sickle cell disease ex: CF- lung disease and poor absorption of nutrients by pancreas, - heterozygotes are protected against cholera, tuberculosis, typhoid

community

All the different populations that live together in an area

Mullerian mimicry

Evolution of two species, both of which are unpalatable and, have poisonous stingers or some other defense mechanism, to resemble each other -reinforces that image, for example: bees and wasps are both black and yellow but evolved independently

positive frequency dependent selection

Phenotypes are favored only when common -extremely rapid decrease in genetic variation -direction selection -rapid fixation ex: mullerian mimicry

founder effect

a small number of individuals exit a population to found (begin) a new population elsewhere, resulting in immediate change in allele freq ex; EVC, huntingtons, tay-sachs

adaption

a trait that increases fitness in a particular environment by solving an environmental problem

intrasexual competition

a) direct fighting using weaponry or body size ex: narwals fight with modified tooth, larger elephants seals win b)better/faster off finding mates -> elaborate antennae and swift movement -ex: atlas moths male with elaborate antennae can detect females better, honey bee males (drones) bigger eyes mean better vision for finding mates c) better at fertilizing egg (after mating) ' sperm competition" -mostly in insects, spermscoops (damselfly) and spermplugs

fitness

ability of organism to solve environmental problems

frequency-dependent selection

abundance of phenotype affects selection -can be positive or neg

optimal foraging theory

animals chose among alternative behavior pick strategies that maximize fitness by optimizing/balancing this ratio benefit/cost

genetic drift

chance changes allele frequencies parameters that affect this -population size -allele freq -time

peacock's tail

confused darwin bc why put so much energy into beauty if it doesn't solve an environmental problem so he developed new theory of sexual selection -restricted to one sex and costly in relation to energy to produce, increases visibility to predators and slows down bird from escaping predators

models of natural selection

directional selection, disruptive selection, stabilizing selection -also heterozygous advantage, freq dependent selection, multiple nich polymorphism

chemical manipulation ex

drosophilla (fruitflies) males inseminate females with chemicals (mimic female hormones)to increase egg laying but decrease female lifespan (toxic to female)

Ellis von Creveld syndrome

example of founder effect -homozygous recessive -rare dwarfism -deleterious allele -amish descended from 200 european settlers in 18th century -1 copy of EVC in heterozygote on this ship

recurrent laryngeal nerve

example of imperfection of homology -recurrent laryngeal nerve functions for speech, breathing, and swallowing, runs from brain to chest cavity by aorta back to throat (reduces speed of nerve impulse bc far traveling, higher material cost to produce) - in fish, have direct route from brain to gill arch (evolved to aorta) to throat -in giraffes- major problem bc long neck

disruptive selection

favors individuals at both extremes of the phenotypic range, intermediates not good! -able to maintain genetic variation -ex: beak size in black bellied seedcrackers- birds with relatively small beaks and birds with relatively large beaks survive ex: jack salmon- incredible migrations, change in body forms and color bigger mates more successful but die after mating jack salmon are little, younger and dont always die after mating

female sexual cannibalism

female eats male for resources after mating -ex: sagebrush crickets- males call, females mount them and begin to chew its wing and drink its blood when mating ex: black widow spider, female large, males sma;ll mall rolls into mouth after insemination, if female eats him, she receive some sperm, some nutrients male dies but gets more offspring

cave lice females

females have penis, why? females wants as much sperm as possible bc there are limited resources in caves and males produce more sperm than needed for mating so females use excess sperm for food/nutrition

sexual deception

fireflies example: light flashing patterns for mating are specific to each species, one female species mimicks mating pattern of another species, males get attracted for mating purposes but female eats him

population

group of individuals

Optimal Diet Breadth

how broad or narrow your diet should be

traumatic insemination

in bed bugs males perforate the female's abdomen and introduces sperm directly into her body cavity (not her reproductive tract) proximal to ovary, females bleed and are susceptible to infection -male squids do this too (SICKO) male advantage: mating success and more offspring female disadvantage: puncture wounds

ecology

is the study of the relationships, distribution, and abundance of organisms, or groups of organisms, in an environment economy of nature by ernst haeckel struggles of existence by darwin 1859

bottleneck effect

no geographical barrier -short term drastic reduction in population size which speeds up the rate of genetic drift ex: lions and flies, grey wolves, cheetahs- almost 99% died and then pop grew back but very little genetic variation so much that skin graft from one to another will not even reject it

directional selection

occurs when natural selection favors one of the extreme variations of a trait -tends to reduce genetic variation ex: more larger seeds have larger selection to bird with larger beaks ex: selection for early ivy flowering plants, make way more seeds the early you flower

what is natural selection?

organism better fit to environment survive and produce more offspring

optimal patch use model

predicts how long a forager should exploit a food patch before moving on to a new one slope = benefit/cost

negative frequency dependent selection

rare phenotypes are favored by selection -more rare the more better off you are -being common reduces fitness and being rare increase fitness ex: right/left mouthed scale eating cichilid fish ex:batesian mimicry

sexual selection

selection caused by differences in mating success, and fertilization success (NOT REPRODUCTION)

homology

similarity of underlying structure IMPERFECTIONS~

prediction 2

species are related, not independent

prediction 1

species change through time

what happens if we remove nonrandom reproduction

there would be no natural selection bc there would be no prediction of which is better (selection) there would be evolution but no adaptions would happen this is referred to as genetic drift

evolution mechanism: good genes

traits preferred: indicate heritable viability adaptive value to chooser: sons/daughters with greater viability, not more offspring just better ones ex: frigate male birds have big balloon chest that is deep red and reflects healthy blood, same with chickens

evolution mechanism: good protectors/ parents/ providers

traits preferred: traits that indicate ability to provide/ protect adaptive value: more resources/ survival = more babies! ex: cardinal males feeds female a seed

evolution mechanism: sensory exploitation

traits preferred: traits that stimulate the senses adaptive value: none sensory system evolved for other reasons just taking advantage of it ex: water mites in freshwater ponds: females detect prey by ripples in water, males mimick these ripples, females predates and then the male mates

vestigial trait

traits that have become nonfunctional overtime

harassment ex

waterstriders males aggressive to females