lecture 21

Question 1

what are major forces of microevolution?

Answer 1

natural selection, genetic drift, migration

Question 2

what is macroevolution?

Answer 2

relationship b/w species and speciation events

Question 3

what is the species problem?

Answer 3

refers to problem of finding the best method to define species
lots of biologists cant define what a species is, reveals problem that there isn’t universal best def of a species

Question 4

what is a flaw of defining species by similar phenotypes?

Answer 4

its difficult to use for allopatric organisms as same species can vary across diff locations
ex. body size varies from poles to equator

Question 5

what does sympatric mean?

Answer 5

organisms which live in same area

Question 6

what does allopatric mean?

Answer 6

organisms living across regions

Question 7

what is taxonomic species concept?

Answer 7

mostly based on morphological diffs, i know it when I see it type

Question 8

what is biological species concept?

Answer 8

defining species based on crossability or reproductive fertility among individuals

Question 9

what is premating/prezygotic isolation and what is this impact?

Answer 9

caused by diff timing for reproduction, diff courtiship behaviors, mechanical differences, and means that there’s the reduction in the number of hybrids as zygote formation + gamete fusion is prevented

Question 10

what does postmating/postzygotic isolation involve?

Answer 10

this is caused by genes combos that don’t work well in hybrids and can’t arise by natural selection, must arise as a byproduct of evolution
there are two types, intrinsic and extrinsic

Question 11

what is intrinsic postzygotic isolation?

Answer 11

abt things which are internal to organism which prevent reproduction of proper hybrid like sterility in hybrids

Question 12

extrinsic isolation?

Answer 12

hybrids have biological disadvantage which makes them more vulnerable to predators/have lower fitness
ex. hybrid butterflies have strange patterns which gives them increased predation risk

Question 13

is evolution or adaption necessary for speciation?

Answer 13

its necessary for ecological speciation

Question 14

what is ecological speciation?

Answer 14

describes cases where local adaption leads to reproductive isolation and consequently speciation

Question 15

how do adaptive radiation related to speciation?

Answer 15

adaptive radiation are a key case of selection and adaption directly leading to speciation

single ancestor leads to many diff species due to diff morphology evoled as adaption to diff resources

Question 16

do some species have a speciation advantage?

Answer 16

yes
ex. finches also radiate a lot on mainland, something abt finches causes naturally high rate/change of radiation which doesn’t occur other species

ex. mockingbirds can be found on the galapagos similar to finches, but have no radiation