Lesson 6: Speciation

Question 1

Species

Answer 1

a population that’s is reproductively compatible. Members of the population can interbreed and produce viable, fertile offspring

Question 2

Speciation

Answer 2

The formation of a new species

Question 3

Reproductive isolation

Answer 3

-the inability to produce viable offspring w/ members of a different species due to some form of biological barrier
—for a species to remain distinct it must become and
remain reproductively isolated

Question 4

Biological barriers- 1. Behavioral isolation

Answer 4

Species specific behaviors that prevent interbreeding among closely related species
Ex- bird song, mating rituals,
pheromones, etc.

Question 5

Biological barriers- Habitat Isolation

Answer 5

Species may live in different habitats and rarely encounter e/o

Question 6

Biological barriers- temporal isolation

Answer 6

Species may share the same habitat but mate at different times or seasons

Question 7

Biological barriers- mechanical isolation

Answer 7

Species are anatomically incompatible

Question 8

Biological barriers- Gametic isolation

Answer 8

Gametes are incompatible. Gametes can not fuse or recognize e/o
—male gametes can not survive in the
reproductive tract of the female.

Question 9

Biological barriers- hybrid inviability

Answer 9

Hybrid embryos between the two species die before birth or fail to develop

Question 10

Biological barriers-hybrid sterility

Answer 10

Hybrids between the two species are unable to produce (meiotic failure) and as a result are sterile

ex— mules: hybrids of horse and donkey

Question 11

Biological barriers—hybrid breakdown

Answer 11

The first generation of hybrids between two species is fertile and viable but the second generation degenerates

Question 12

Allopatric speciation

Answer 12

Speciation that occurs as a result of a population becoming geographically isolated from the parent population

Question 13

Process of allopatric speciation

Answer 13

-geographic isolation can occur due to the formation of physical barriers such as mountains, canyons, rising sea leaves, glaciers, etc.
—> the physical barriers prevent gene flow b/t the two populations
—> the different populations are subjected to different selection pressures causing allele frequencies of genes to change
—> the two populations accumulated sustain genetic differences so that they become reproductively isolated and are unable to interbreed

Question 14

Sympathetic speciation

Answer 14

-speciation occurring as a result of the restriction of gene flow b/t members of a population due to ecological isolation (niche differentiation) or polyploidy (search this up)

Question 15

Process of sympathetic speciation

Answer 15

-some members of population may be better adapted to a slightly different habitat in an ecosystem and begin to specialize in that habitat
—> diff. selective pressures in the two habitats leads to genetic changes in the organisms
—> the two populations become reproductively isolated
—> alteration in behaviour, chromosomal mutations, non-random mating , altered gene flow are all factors leading to sympathetic speciation