Flashcards
Evolution
Flashcards do conjunto (55)
- 1-Why does the toad have eyes in its mouth?-due to a mutation, which causes different phenotypic expression
- 2Briefly name the 5 mechanisms of evolution1.Mutation
2. Natural Selection
3. Sexual Selection
4. Gene flow
5. genetic drift - 3Mutation: -Why are these important? -How do they work? -What are alleles? -What are deleterious mutations?-they are the basis of all evolution (ultimate source of genetic variation)
-change in genetic code, means change in alleles (change amino acid sequence/alter gene expression), MAY have phenotypic effects
-alternative expression of same gene
-decrease fitness - 4-What do we understand from fruit flies? -What are hopeful monsters?-That most mutations are not good (because harder to fix something that is not good than hurt it)
-hopeful monsters: big changes that are good aka x ray vision - 5-What is mutation accumulation in the lab?-Flie populations, with some they are control and others they intervene to make sure that they do not die even when mutation decreases their fitness, then at end found that without NS fitness would be decreased by 2% every generation
- 6-what is genetic drift? -in what kind of pops does this work the most?-independent on natural selection, part of the population randomly gets killed off (which changes makeup of gene pool)
-squirrels in cold, meteor --> random
--> variation of relative frequency of different genotypes in a small pop owing to chance disappearance of particular genes
-in small pops, where there is not much diversity to begin with - 7-Fruit flies and eye colours-started with equal allele frequencies in both pops, and you can see them fixing for either eye colour over time (randomly)
- 8-Another way to think of evolution besides allele frequency? -3 aspects of this? -examples? -are most traits single allele or quantative?-quantatative traits: average of some trait in the population
-1. Traits are influenced by MULTIPLE genes (POLYGENIC)
2. Traits are usually influenced by environment conditions
3. typically leads to continuous variation of a trait
-height, IQ, swimming times
-most are quantative (changes in allele frequency at multiple genes underlie these changes) - 9Natural Selection -does this involve alleles or quant traits? -who came up with it? What were their 4 main insights? What was their prediction? -What is Darwin's example of the power of selection?-quant traits
-Darwin and Wallace:
1. That pop should increase quickly (like Malthus said), so for it to be stable there must be a lot of death
2. traits are variable among individuals
3. traits influence survival
4. traits are heritable
-Their prediction was that survival should increase in frequency through time
-domestic breeds (also flies and their bristles) - 10-What was the importance of the 1976 Daphe Major Drought? (scenario, observation, conclusion)-On an island that goes through droughts and rainy years, drought years the plants would have little production, so all the seeds would get eaten quickly and the only seeds left on the ground were the large, hard one that none of the birds could eat. Finches declined dramatically, and could see that the decline was related to their beak sizes: G fortis was more likely to survive (had larger beaks)
Conclusion: traits influence survival! - 11Daphe Major pt 2... -What about the heritability of traits? -was there evolution in ONE generation?-They could see that beak size was a trait passed down to young (relationships graphed)
-YES! graph showed move over the larger beaks (makes sense, if it influences survival and is heritable)
--> allele frequency change - 12Sexual Selection -What is it? -What are the 2 forms? -Relationship with natural selection? -Widow birds -Mosquitofish-It is natural selection arising from preference by one sex for a certain trait in individuals in the other sex
-INTRA and INTER
-they work against each other/compromise
-widow birds: very long tail, bad for natural selection but good for sexual selection!
-gonopodia: sneaky and attract mate: a drag though... in places where there were no predators it got larger than usual - 13Gene Flow -What is it? -What is its effect on divergent natural selection?-the flow of genes between populations
-harder to select for one gene when there is new diversity (fruit flies were not able to choose one eye colour when pops were mixed) - 14Explain the Drunkard's Walk-His position was his allele frequency
-Every step forward was a generation
-Left alone, he would stumble back and forth until he ended in the ditch (random, genetic drift, fixed)
-he would stay in ditch unless there was a bump on the wall/good samaritan: these are mutations
-NS would be the road having a tilt pushing him one way
-sexual selection is woman calling for him (against the tilt)
-gene flow would be if someone was attached to him: he could not fix to one side that quickly
-bigger man/more inertia = bigger pop - 15-Natural selection does not create diversity of life, what do you need for that?-Speciation (some way of breaking off species/reproduction barriers)
- 16-What are the 3 major species concepts? (what is a species concept)1. Biological
2. Phylogenetic
3. Morphological/typological
(way of defining whether two species are the same or not) - 17-describe typological-look at morphology, have one ideal of the species and compare, Linneas and bird books
-this does not account for how much variation there is btwn species (think of anglar fish from different sexes or butterflies mimcry) - 18-what is amazing about dogs?-they have as much skull morphology diversity within their species than all the carnivora (and are exploring new area/new morph space)
- 19-Explain phylogenetic species concept-Based on tree/phylogeny, if something can tie its lineage back to one thing faster than another
-this just shows time, not why there would be reproductive barriers and cannot be used for fossils since relies on DNA - 20-What is bio species concept? -what are the problems with it?-the major one
-you are the same species if you can reproduce successfully with the other
-this does not just mean if you CAN reproduce, but if you WILL (includes different behaviour, different countries)
-allows for some gene flow
-hard to see this in the fossil record, and hard to know if things would reproduce if they could - 21-Important note about speciationIt's not an event, it is a process!
- 22Name the 7 mechanisms for speciation-Gene flow
-Divergent natural selection
-UNIFORM natural selection
-sexual selection
-genetic drift
-polypoidy
-hybirdization
-cytoplasmic incompatibility - 23Explain uniform natural selectiontwo sides of room separated by a wall, both sides experience same change, both experience mutations that will benefit and change their genes, if these are not the same/ not compatible, when they are brought back together they may not mate
AKA adaptation to same change in environment through different mutations to create incompatibility - 24How is genetic drift a mechanism of speciation?-one side has a meteor and the other does not, come back together may not have fixed the same and are incompatible
- 25-explain polypoidy -explain hybridization-genome duplication occurs in a part of the pop and not the other
-hybirds cannot mate with others but can mate with themselves (can create 3 species) - 26-explain sexual selection in the context of speciation-one hair colour favoured on one side, another on the other...
- 27-explain DIVERGENT natural selection (ECOLOGICAL SPECIATION)-one side gets hotter, the other colder, will not evolve the same
- 28-what are the two parts of divergent natural selection (basically very similar to others)1. Disruptive/divergent selection drives adaptive divergence
2. Reproductive barriers evolve - 29-Darwin's Finches: what is thought to drive this speciation? -name the three species, what separates them?-the type of resource they feed on/beak morphology
-G fuliginosa (small), G fortis (medium), G magnistrosis (large) - 30-how did they use more subtle variation to understand how adaptation to different environment has caused reproductive barriers? -4 parts of this:-by looking just at the middle group; fortis: there is a lot of variation within it, so you could expect that with time it will separate out so that none feed on the middle
1. the two feed on different foods (ecological contrast)
2. intermediate birds have low survival (disruptive selection)
3. each mate should mate with same morph (mating isolation)
4. the morphs should become rep isolated - 31-what evidence was shown to support these predictions1. prove that they feed on different things
2. prove that the ones that feed in the middle die off (graph of fitness and beak size --> cool graph)
3. Plotted and saw mated within morphs - 32What do these various concepts tell us?That though divergent NS is primary driver in evolution of biodiversity, it cannot be everything (birds of paradise has sexual selection driving new species)
- 33-What is sexual conflict?1. females are the limiting resource, so they have selection to resist males
2. there are then reduced mating rates for males
3. males have selection to overcome this
4. Increased mating rates
runaway process that loops back to top and creates new species - 34For example, water striders-Females develop ways of kicking males off, males of attaching to females
-if they have developed separately, they will not be able to mate with the other (or will kill/not succeed) - 35-explain cytoplasmic incompatibilityhas nothing to do with NS from env or sexual selection...
WOLBACHIA: transmitted in cytoplasm btwn generations so only thru females
when a male infected tries to mate with a female not infected, wolbachia knows not to allow the offspring because will not have passed it on
-two parts of the room, one side has different wolbachia than other, mating will not be successful (wasps, fixed them tho) - 36-What is ecology? -What are the 3 forms?Study of interactions btwn organisms and their environment
-behavioural
-population
-community (interactions in btwn species in relation to the env) - 371. Behavioural ecology what kinds of questions can be asked-how do animals decide what to eat?
-how does altruistic behaviour evolve? - 38How do animals decide what to eat? -What is the standard prediction?Through foraging theory, we expect animals to eat what will require the least amount of energy for the most benefit --> animals eat food that MAXIMIZES their energy intake
- 39-what are factors (3) to consider tho?1. catchability
2. abundance
3. quality - 40Bear and salmon exampleBears feed on salmon, especially during egg laying, salmon do not feed/die during this period SO they are the most energy rich at the beginning
By foraging theory, they should eat them ASAP to maximise their energy
BUT that ends of depending on other things, like catchability (fast water vs slow water) - 41Other complications of foraging theory that we can see with bears?-Predation (guppies)
-Competition
-essential nutrients (macaws on clay) - 42Altruistic behaviour: why does it evolve-animals may preferentially help their kin
-group selection (be nice and your group will do well)
-reciprocal altruism
-punishment
-gaining experience - 432. Population ecology: what are some Qs-pop decline and recovery (atlantic cod: increase in seal? allee effect? change in life history traits? cohort effect?)
-pop cycles (lemmings, Kluane Yukon: predators (lynx and hare), competition (herbivory in rabbits), stress)
Yukon: enclosures showed both predation and food availability were a part of it - 443. Community Q -name 3 categories of species interactions-why is there varying number of species across the globe?
1. Predation/parasitism
2. Competition
3. Mutualism - 45-What is evolutionary conservation biology?thinking about evolution has shaped biodiversity in the present, how it will influence fate of organisms in the future
- 46-Name the 3 components1. Preserving for evolutionary history/diversity
2. Preventing inbreeding depression
3. Incorporating contemp evolution into conservation strategies - 47-what are the 3 aspects of conserving for evolutionary history/diversity1. looking at lines that are distinct (EDGE concept)
2. looking at places that have a lot of these 3. considering variety within species just as important as separate species - 48-how do we conceptualise adaptation?-mean size of traits (if some thing is better for that ecological condition, pop will evolve to adapt and move towards optimum)
- 49What are the 2 possible scenarios in the face of env change?1. abrupt shift (oil spill)
2. gradual (global warming--> has to follow with a small lag or will go extinct)
SO its a race btwn making fitness better and the cost of being maladapted - 50-what are the two ways pops can match their phenotypes to the env?-move to another location
-stay and change phenotype - 51-what are the two ways to change the pheno?1. Evolution
2. Plasticity (no gen change) - 52-what did their meta analysis show?-calculated rates of evolution with Haldane metric (divided by generations)
could see that the most dramatic changes have been made by humans, especially when they are intending to kill
--> when humans get involved, evolution speeds up (rise above natural variation) - 53-what does evolutionary dynamics do and show?-asks about the consequences of the fast evolutions that we are seeing, shows that the arrow goes both ways (eco evo evo eco)
eco change means selection and plasticity, pheno changes, gen changes thru inheritance, feeds back and changes pop and ecology - 54-what is evolutionary rescue? what does it show? -does this happen in nature?-evolution allows you to persist/survive in changing env (keeps pop out of risk zone) eg yeast and salt
-the guppies in trinidad - 55-how does this fast evolution feed back and change eco? -what do alewife show?-alewife: raker: zooplankton: just as much change as if there were no fish!
-eco importance of instraspecific variation
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- FlashCards sobre Evolution , criado por Emma Burbidge em 20-12-2017.
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