Ch 3 Natural Selection II- Evolution

What is Darwinian Fitness?

the ability of an individual to SURVIVE and REPRODUCE

What does Darwinian fitness measure?

the variable of success in reproduction (a relative measure, not absolute

Example for sexual selection

female tungara frogs prefer male calls with more chucks

Example of natural selection

bats locate chucking males better than non-chucking males

Is natural selection or sexual selection stronger?

sexual selection, most males chuck bc more frogs than bats

Are bats response to tungara frogs call nature or nurture?

nature

Can you condition bats to respond to a marine toad rather than a tungara frog call?

yes, reinforcement learning can allow them to overcome initial response

T or F: Natural selection acts on individuals, but its consequences occir in populations

True

How do you see if selection has occurred in a population?

Will not see it during for example a drought, the finches either survive or don’t (selection part), but you can measure the offspring and see if the trait is heritable to see if evolution occurred (in a population)

Does natural selection act on phenotypes of genotypes?

Phenotypes and evolution requires these phenotypes to genetically change and be inherited

What does evolution cause genetically?

a change in allele frequencies overtime

Is natural selection forward looking?

No, it is based on the current environmental pressures at that time

Evolutionary anachronism

occurs when a species possesses traits or adaptions that evolved to interact with another species that has now gone extinct. The surviving organism though retains these features that appear useless

Evolutionary anachronism example

osage orange, honey locust, and avocado are all large fruits that were originally mad for not squirrels or small mammals to eat but sloths and others

pronghorns can run up to 55mph and was originally this fast to escape the now-extinct american cheetah

Do you real cases of altruism exist in nature?

No, even in ground squirrels, the female squirrels that normally make alarm calls do it for their family around so their genes live on

How does natural selection create new traits if it acts on existing variation?

Mutation which gives a constant source of variation for selection to act on

Artificial selection example

corn kernel oil content which was mutated to supply to new variation to act upon to pick the new most beneficial traits

Adaptation

a feature that promotes fitness and evolved by selection for its current role

Pre-adaptations definition

a trait that originally evolved for a specific function and later proved useful for a completely different function in a new ecological role

Pre-adaptations examples

feathers in dinosaurs originally for thermal insulation but later provided structure need for flight

wing in common murre allow it to dive more effectively but originally for flying

Exaptation

implies that the pre-existing organ or structure becomes converted to the extent that its no longer functional for its original use

example: penguins and there wings

Is natural selection random?

No, the mutation is but selection acts on variation in a nonrandom way choosing genetic variants that aid in reproduction and survival

Dollo’s Law

an organism cannot return to an exact former state that existed in its ancestral history (once lost in evolution are not regained in original form

Example of Dollo’s Law

teeth in birds: ancestral birds had teeth but overtime lost them to beaks, modern birds do not even have teeth even if they need them and evolve a sharp beak instead

panda thumbs: pandas not to grip bamboo but have already evolved a fixed foot structure, so instead evolved an enlarges wrist bone as a false thumb

SAME FUNCTION BUT DIFF GENE ACTIVATED