Species and speciation

Question 1

explain the morphological species concept

Answer 1

defines a species by similar structural features.
applies to sexual and asexual organisms.
works for extinct species.
relies on subjective criteria.

Question 2

how do biologists avoid cryptic species

Answer 2

1. examinations in morphology.

2. molecular phylogeny to test for historical reproductive isolation.

Question 3

disadvantage of morphological species

Answer 3

organisms may look similar but be molecularly different

Question 4

where does allopatric speciation occur

Answer 4

(other country) islands, rivers and mountains.

eg a canyon may create a small barrier for rodents but not birds

Question 5

where does sympatric speciation occur

Answer 5

(same country) reproductive barrier within a habitat

occurs when organisms have morphologically favoured differences

Question 6

how many genetic differences evolve

Answer 6

mate choice.
sensory perception.
hormone signalling.

Question 7

state the 2 main types of reproductive isolation

Answer 7

prezygotic.

postzygotic.

Question 8

state factors that contribute to prezygotic isolation

Answer 8

habitat isolation.
temporal isolation.
behavioral isolation.
mechanical isolation.
gametic isolation.

Question 9

state factors that contribute to postzygotic isolation

Answer 9

produces a hybrid.
reduced hybrid fertility.
hybrids dont survive.
hybrid breakdown.
reduced gene flow.

Question 10

3 outcomes of a hybrid zone

Answer 10

reinforcement.
fusion.
stability.