Mechanisms (Evolution)

Question 1

traits

Answer 1

can be preferentially selected for or against which can cause rise of a new species

Question 2

disruptive selection

Answer 2

two extreme traits are preferentially selected for

moderate traits slowly become less common and then disappear

Question 3

stabilizing selection

Answer 3

extreme traits are preferentially selected against

moderate traits become more common and extreme traits become less common and slowly disappear

Question 4

directional selection

Answer 4

when a trait moves slowly over time towards one extreme

Question 5

4 ways of evolving

Answer 5

divergent, convergent, parallel, coevolution

Question 6

divergent evolution

Answer 6

when two or more related species become more and more dissimilar
ex. red fox and kit fox

Question 7

red fox and kit fox

Answer 7

example of divergent evolution
evolved differently because of their environments
red fox- farmland and forests
kit fox- deserts

Question 8

convergent evolution

Answer 8

unrelated species become more and more similar

adapting to the same environment

Question 9

American cactus and African euphorbia

Answer 9

example of convergent evolution

adaptations help to store water and protect themselves from predators

Question 10

parallel evolution

Answer 10

2 species with similar characteristics evolve similar traits in a similar timeframe
might be due to being exposed to similar/identical selective pressures
aren’t necessarily interacting with each other

Question 11

coevolution

Answer 11

joint evolution of 2 or more species in close interaction

Question 12

evolution of predators and their prey

Answer 12

example of coevolution

Question 13

bats and the flowers they pollenate

Answer 13

example of coevolution
bats adapt to be better at retrieving pollen
flowers adapt to be lighter in colour so the bats can see them better

Question 14

species

Answer 14

the event by which a new species arises

Question 15

Ernst W. Mayr’s definition of a species

Answer 15

1. can breed or reproduce with one another
2. produces offspring of both sexes that are capable of reproducing offspring of both sexes
3. do not ordinarily breed with organisms from another group

Question 16

requirements for a mating

Answer 16

have to be in physical contact

Question 17

mechanism for speciation

Answer 17

geography

natural selection leads to speciation

Question 18

requirements for the rise of a new species

Answer 18

1. must arise independently from an existing species

2. cannot breed with cousins in the same species

Question 19

reproductive barriers

Answer 19

1. pre-zygotic
2. post-zygotic
   ensure that inbreeding doesn’t happen- essential in the rise of a new species

Question 20

pre-zygotic barriers

Answer 20

all the things that can prevent mating

Question 21

examples of pre-zygotic barriers

Answer 21

geographical isolation
ecological isolation
ethological isolation

Question 22

geographical isolation

Answer 22

cannot mate because they are not in the same geographical area

Question 23

ecological isolation

Answer 23

can be in the same geographical are but different niches

Question 24

ethological isolation

Answer 24

behaviour based

not sexually attracted

Question 25

post-zygotic barriers

Answer 25

only in hybrid species

ex. mules- cannot successfully have offspring

Question 26

4 types of speciation

Answer 26

1. allopatric
2. peripatric
3. parapatric
4. sympatric

Question 27

allopatric speciation

Answer 27

when a geographical location is physically divided
selective pressures in different geographical locations cause sub-populations to evolve differently
earthquake, moving glaciers, drifting continents

Question 28

peripatric speciation

Answer 28

no geographical division
a new colony is established
new colony cannot go back (for some reason) and therefore don’t mate with initial population

Question 29

parapatric speciation

Answer 29

new colony in continuous or adjacent to the population it divided from
ex. mountain goats that moved farther up the mountaine

Question 30

sympatric speciation

Answer 30

ethological pre-zygotic barriers
based on mating rituals
no geographical barriers
ex. bowerbird that builds nests to attract females
new species within the existing population