The Origin of Species

Question 1

what is speciation?

Answer 1

-the process of forming new species
-based on the idea that species are what create biological diversity

Question 2

what is macroevolution?

Answer 2

changes in evolution above the species level

Question 3

what is the biological species concept?

Answer 3

-a population that can interbreed and produce viable/fertile offspring is a SPECIES
-a SPECIES cannot breed and produce viable, fertile offspring with another species

Question 4

what are the two big reproduction barriers for interspecies breeding?

Answer 4

-prezygotic barriers = prevent mating between species
-postzygotic barriers = prevent zygote from developing into a viable adult

Question 5

what are the five prezygotic barriers?

Answer 5

-habitat isolation
-temporal isolation
-behavioral isolation
-mechanical isolation
-gametic isolation

Question 6

what is habitat isolation?

Answer 6

-a prezygotic barrier referring to physical location constraints that do not allow two species to interbreed

Question 7

what is temporal isolation?

Answer 7

-a prezygotic barrier referring to species being unable to interbreed because they mate in different times of the year / seasons

Question 8

what is behavioral isolation?

Answer 8

-a prezy. barrier referring to different species not being able to mate due to having different “mating practices” [ex - bird dances / songs]

Question 9

what is mechanical isolation?

Answer 9

-a prezy. barrier referring to when different species can try to mate - but their genetalia will not allow them to

Question 10

what is gametic isolation?

Answer 10

-a prezy. barrier referring to two different species having incompatible eggs & sperm, meaning a zygote cannot be formed

Question 11

what are the 3 postzygotic barriers?

Answer 11

-reduced hybrid viability
-reduced hybrid fertility
-hybrid breakdown

Question 12

what is reduced hybrid viability?

Answer 12

-when an interspecies offspring can occur, but is too weak or unviable to survive and reproduce on its own

Question 13

what is reduced hybrid fertility?

Answer 13

-when an interspecies offspring can occur, but it is infertile, meaning more offspring of this kind cannot occur [ex - mules]

Question 14

what is hybrid breakdown?

Answer 14

-when an interspecies offspring can exist, but the offspring of the interspecies offspring [F2] is weak or sterile

Question 15

what are the limitations of the “species” term? aka what does it not apply to?

Answer 15

does not apply to:
-asexual organisms
-fossils
-organisms where we don’t know much about how they reproduce

Question 16

what are the two ways speciation can occur?

Answer 16

-allopatric speciation
-sympatric speciation

Question 17

what is allopatric (“other country”) speciation?

Answer 17

-“new” species develops as a result of isolation from parent species’ habitat
-this variation leads to speciation in the new setting
-“geographic isolation”

Question 18

what is sympatric (“same country”) speciation?

Answer 18

-a new species developing in the same region as the parent population due to polyploidy
-polyploidy = improper meiotic division leading to a cell having an extra set of chromosomes