lecture 20- origin of species

Question 1

what is macroevolution

Answer 1

evolutionary change above the species level
origin of a new species or cumulative evolutionary change of a long period of time

Question 2

what is speciation

Answer 2

when species split into 2 or more species (new species)

Question 3

what does the biological species concept refer to

Answer 3

reproductive isolation
species are organisms who can breed together in nature and produce viable and fertile offsprings for multiple generations
cannot produce viable and fertile offsprings with members of other species

Question 4

what does reproductive isolation entail

Answer 4

existence of biological factors that impede members a two species from producing viable and fertile offsprings
preserving genetic integrity (no gene flow)

Question 5

types of isolating mechanisms

Answer 5

prezygotic barriers (5 types): prevent mating or fertilization, zygote is never produced
postzygotic barriers (3 types): prevent hybrid zygote from developing into viable and fertile adult

Question 6

types of prezygotic barriers

Answer 6

habitat isolation
temporal isolation
behavioural isolation
mechanical isolation
gametic isolation

Question 7

what is habitat isolation

Answer 7

different habitats for mating

Question 8

what is temporal isolation

Answer 8

mate at different times of the year

Question 9

what is behavioural isolation

Answer 9

courtship rituals are specific to species so females wont mate with different species

Question 10

what is mechanical isolation

Answer 10

genitals dont align

Question 11

what is gametic isolation

Answer 11

sperm cannot fertilize other species egg (cant penetrate, cant survive)

Question 12

what are the postzygotic barriers

Answer 12

reduced hybrid viability
reduced hybrid fertility
hybrid breakdown

Question 13

what is reduced hybrid viability

Answer 13

hybrid is frail/doesnt make it to birth
dies easily

Question 14

what is reduced hybrid fertility

Answer 14

hybrid is sterile but strong

Question 15

what is hybrid breakdown

Answer 15

first gen. can survive and reproduce but second is weak or sterile

Question 16

what cant the biological species concept be applied to

Answer 16

asexual organisms
organisms that we dont know the reproduction system of

Question 17

what is the morphological species concept

Answer 17

characterization of a species based on visible characteristics

Question 18

what is the ecological species concept

Answer 18

views a species in terms of its ecological niche

Question 19

what is the phylogenetic species concept

Answer 19

traces the phylogenetic history of organisms

Question 20

how does speciation happen

Answer 20

allopatric speciation: geographic separation
sympatric speciation: same area

Question 21

what is allopatric speciation

Answer 21

geographically separated
gene pools diverge
mutations and genetic drift
change enough and cant breed with other pop. and make fertile offsprings
-> new species

Question 22

what is sympatric speciation

Answer 22

occurs through
changes in ploidy (plants)
changes in ecology (animals)

Question 23

autoploidy

Answer 23

extra chromosomes: 2n in gametes instead of n
cant mate with parent plant but can self pollinate with other tetraploids of the same species

Question 24

allopolyploid

Answer 24

parents (different n) result in offspring having an odd number of chromosomes making it sterile with other parent species but fertile with other polyploid hybrids
if the hybrid doubles its chromosomes it can perform meiosis and make gametes

Question 25

changes in ecology

Answer 25

habitat: changes in environment benefit individuals with different alleles and the species splits
sexual preferences: mate choices may change who mates and produce new species

Question 26

theories for the rate of evolutionary change

Answer 26

gradualism: continuous over long periods of time
punctuated equilibrium: evolution over short periods of time
both can be used

Question 27

what is the gradual refinement of existing structures

Answer 27

its in the name
natural selection can only improve a structure in the context of its current utility

Question 28

what does a mutation in genes that control development do

Answer 28

change in the rate/timing of developmental events

Question 29

what does a mutation in genes that control spacial organization do

Answer 29

prompts cell to develop into structures appropriate for a particular location (hox genes provide positional information in animal embryo)

Question 30

what is an important aspect of evolution

Answer 30

extinction

Question 31

how is extinction important for evolution

Answer 31

produces adptive zones that facilitate evolution

Question 32

what is an adaptive zone

Answer 32

ecological niche not filled by ancestral organism
speciation fills the empty ones (less competition, more food, can diversify)