Evolution Cont'd

Question 1

is natural selection the main process behind most evolution?

Answer 1

yes

Question 2

disruptive

Answer 2

type of natural selection

both extreme morphs are selected for and the average morph is selected against

ex. cameroon seed cracker birds (large/small beaks successful, medium beaks unsuccessful)

Question 3

stabilizing

Answer 3

type of natural selection

both extreme morphs are selected against and the average morph is selected for

ex. human birth weight (7 lbs.)

Question 4

directional

Answer 4

type of natural selection

one extreme morph is selected for

ex. TB amino acid 153 point-mutation

Question 5

speciation

Answer 5

the splitting event of one species into 2 or more species

2 types

3 definitions

Question 6

2 types of speciation

Answer 6

allopatric

sympatric

Question 7

allopatric speciation

Answer 7

geographic barrier

ex. stream/Darwin’s finches

Question 8

sympatric speciation

Answer 8

speciation that occurs in the same area

ex. birds of paradise in Papua New Guinea

Question 9

3 definitions of speciation

Answer 9

biological species constant (we use this definition)

phylogenetic species

morphospecies

Question 10

biological species constant

Answer 10

reproductive isolation

in nature, speciation occurs and populations no longer interbreed and produce viable, fertile offspring

Question 11

phylogenetic species

Answer 11

smallest phylogenetic grouping of phylogeny

ex. variation in horseshoe crab species

Question 12

morphospecies

Answer 12

based on morphology (organisms that look alike are same species)

Question 13

hybrid

Answer 13

offspring from two different species

Question 14

barriers that prevent hybridization

Answer 14

maintains speciation

2 types

Question 15

2 types of barriers that prevent hybridization

Answer 15

pre-zygote

post-zygote

Question 16

pre-zygote barriers

Answer 16

prevent formation of zygote

isolation events: habitat, temporal, behavioral, mechanical, gametic recognition

Question 17

habitat

Answer 17

1 species is aquatic, 1 is terrestrial

ex. garder snake

pre-zygote

Question 18

temporal

Answer 18

1 mates in late winter, 1 mates in late summer

ex. spotted skunk

pre-zygote

Question 19

behavioral

Answer 19

bouncing tempo is species specific

ex. courtship dance of fruit-fly

pre-zygote

Question 20

mechanical

Answer 20

genitalia doesn’t fit, 1 is clockwise, 1 is counterclockwise

ex. snail shell direction

pre-zygote

Question 21

gametic recognition

Answer 21

egg proteins only recognize same species

ex. sea urchin

pre-zygote

Question 22

post-zygote barriers

Answer 22

zygote forms but hybrid is unlikely to survive

isolation events: reduced viability, reduced fertility, hybrid breakdown

Question 23

reduced viability

Answer 23

offspring don’t survive to reproductive age

ex. salamander

post-zygote

Question 24

reduced fertility

Answer 24

offspring survive to adulthood, but can’t reproduce

ex. mules

post-zygote

Question 25

hybrid breakdown

Answer 25

subsequent generations of hybrids are no longer viable

ex. rice

post-zygote

Question 26

species

Answer 26

group of living organisms consisting of similar individuals capable of exchanging genes or interbreeding