Natural Selection & Adaptation

Question 1

natural selection

Answer 1

any consistent difference in fitness among different classes of biological entities

Question 2

4 ways non adaptive traits can persist

Answer 2

as byproducts of adaptive traits

due to drift, resulting in random changes in allele frequency

vestigial traits that are now useless

by association (physical linkage on the chromosome) with an adaptive trait

Question 3

3 ways to tell if a trait is adaptive

Answer 3

highly complex and energetically expensive

experiments show decreased fitness in organisms without the trait

it has evolved convergently multiple times

Question 4

altruism

Answer 4

benefits another individual - found in social species
ex. honey bees, slime mold

Question 5

kin selection

Answer 5

the gene of an individual is still partially passed on if they increase the fitness of close relatives through altruism

Question 6

cooperation is most common when

Answer 6

organisms will encounter the same other organisms repeatedly

Question 7

group selection

Answer 7

when natural selection occurs to a group instead of an individual
can happen in small social groups with altruistic behavior ex. lions hunting for the pack

Question 8

transposable elements

Answer 8

selfish genes that can self-replicate within a genome

Question 9

medea elements

Answer 9

selfish genes - kill embryos that do not carry that element
the gene contains a maternal toxin and only offspring with the gene for the zygotic antidote can inherit the trait and survive
* complex topic!

Question 10

gene drives

Answer 10

non-Mendelian inheritance of a gene - passes to more than 50% of the population
selfish genes
propels the gene through a population quickly

Question 11

pre-adaptation

Answer 11

an adaptation for one condition which turns out to be also adaptive when another condition arises

Question 12

exaptation

Answer 12

an adaptation that is fine tuned/modified for a new condition - ex. penguin wings used for swimming