evolution chapter 9

Question 1

what is a population

Answer 1

organisms of same species that live in a specific area

Question 2

micro-evolution

Answer 2

small scale evolution
- change in gene frequencies within a population over time

Question 3

macro-evolution

Answer 3

evolution on a grand scale
- changes occur over a long period of time

Question 4

genetic equilibrium

Answer 4

stable condition of a population in which an allele frequency remains the same over generations

Question 5

allele frequency

Answer 5

percentage of any specific allele in a gene pool
- when frequency of allele changes

Question 6

what factors change the allele frequencies of a population

Answer 6

• mutations
• gene flow
• non-random mating
• genetic drift
• natural selection

Question 7

mutations

Answer 7

• changes in dna of individual
• provide new alleles in population and may provide variation required for evolution to occur
  ex: norway rat- warfarin resistant rats in norway caused increase in rat population

Question 8

gene flow

Answer 8

net movement of alleles from one population to another
ex: grey wolf- may mate with member of nearby population to bring new alleles

Question 9

what are the 3 types of mutations

Answer 9

beneficial, neutral, harmful

Question 10

beneficial mutations

Answer 10

potential to increase an individuals ability to survive or fitness

Question 11

neutral mutations

Answer 11

don’t affect an individual’s ability to survive or fitness

Question 12

harmful mutations

Answer 12

occur most often, environment selects against them, results in rare alleles
ex: cystic fibrosis

Question 13

compare how a small population vs. large population would be affected by genetic drift

Answer 13

smaller the population, less likely that parent’s gene pool will be reflected in next generation, vice versa

Question 14

what are the 3 types of natural selection
(know graphs)

Answer 14

• stabilizing
• directional
• disruptive

Question 15

difference between founder’s effect and gene flow

Answer 15

founders: starting a new population
gene flow: increases genetic diversity- may help population survive

Question 16

define species

Answer 16

group of interbreeding organisms that share gene pool and produce fertile offspring
- isolated from other species
- same species can exchange genes

Question 17

what are the 5 types of pre-zygotic mechanisms

Answer 17

(prevention of mating)
- behavioural isolation
- temporal isolation
- ecological habitat isolation
(prevention of fertilization)
- mechanical isolation
- gametic isolation

Question 18

behavioural isolation

Answer 18

behaviour that prevents interbreeding with closely related species
ex: mating rituals

Question 19

habitat isolation

Answer 19

species in same area occupy different habitats, rarely encounter each other
ex: garter snakes in water and meadows

Question 20

temporal isolation

Answer 20

species kept separate due to timing barriers, mate at different times (seasons, years, etc.)
ex: flowering

Question 21

mechanical isolation

Answer 21

related species anatomically different, can’t mate
ex: variations in flower structure prevent pollination

Question 22

gametic isolation

Answer 22

sperm can’t reach or fertilize egg
ex: plants may land on stigma- fertilization doesn’t occur

Question 23

what are the 3 post-zygotic mechanisms

Answer 23

• hybrid inviability
• hybrid infertility
• zygote mortality

Question 24

hybrid inviability

Answer 24

develops but can’t survive to maturity
ex: cotton plants- produce weak and sterile seeds

Question 25

hybrid infertility

Answer 25

two species can mate but hybrid is sterile and can’t reproduce
ex: horse (female) and donkey (male) -> mule (sterile)

Question 26

zygote mortality

Answer 26

genetic differences may stop development of zygote
ex: sheep and goat hybrids -> fertilization occurs but zygote doesn’t survive

Question 27

co-evolution

Answer 27

2 or more species changing due to changes in a species in which they are interacting with
ex: bumblebee orchids look like female bumblebees

Question 28

how do humans reduce habitats

Answer 28

habitat loss
- being removed or destroyed
- becoming fragmented
- being charged or degraded
- being too frequently used by humans

Question 29

preferred phenotypes

Answer 29

choose mates based on physical or behavioural traits
ex: caribou

Question 30

inbreeding

Answer 30

mating between relatives
ex: pea flowers