Speciation

Question 1

Speciation

Answer 1

Development of new species - environmental factors change the populations so much they no longer meet the criteria - macroevolution

Question 2

Speciation is caused by….

Answer 2

Reproductive isolation

Question 3

Prezygotic Isolating Mechanisms

Answer 3

Pre-fertilization barriers - stopping zygote formation and development between different species

Question 4

Behavioral Isolating Mechanisms

Answer 4

Any behavior or special signal that is species specific. Eg, Bird songs

Question 4

Habitat Isolating Mechanisms

Answer 4

Species live in the same region, but different habitats, Eg. common garter snake vs. Northwest garter snake

Question 5

Temporal Isolating Mechanisms

Answer 5

Timing barriers - may occupy same habitat but mate or flower at different times. Eg. Orchids bloom for one day each

Question 6

Mechanical Isolating Mechanisms

Answer 6

May mate, but fail to achieve fertilization due to anatomical incompatibility. Eg. Flower structure + pollinators

Question 7

Gametic Isolating Mechanisms

Answer 7

Gametes prevented from meeting after mating, Eg. reproductive tract of females destroy gametes of other species

Question 8

Post - Zygotic Isolating Mechanisms

Answer 8

If zygote forms - barriers prevent hybrid zygotes from developing viable + fertile individuals

Question 9

Hybrid Inviability

Answer 9

Genetic incompatibility - no zygote development

Question 10

Hybrid sterility

Answer 10

Offspring are viable, but not fertile - no further reproduction. Eg. Mule

Question 11

Hybrid Breakdown

Answer 11

Sometimes hybrids are viable and fertile for one generation but next generation is sterile and weak. Eg. rice

Question 12

Sympatric Speciation

Answer 12

Same geographical area but reproductively isolated, common in plants that self pollinate

Question 13

Allopatric Speciation

Answer 13

Caused my geographical barriers. eg, ocean levels, natural disasters

Question 14

Adaptive radiation

Answer 14

Diversification of common ancestral species into various new species. Eg. Darwins finches

Question 15

Explain Darwin’s finches

Answer 15

New island and they were able to fill all the ecological niches. New species formed but believed from a common ancestor.

Question 16

Divergent evolution

Answer 16

common ancestor becomes increasingly distinct… AA —-S/T

Question 17

Convergent evolution

Answer 17

2 unrelated species become similar based on selective pressures…..AT—–S/S

Question 18

Gradualism

Answer 18

slow and steady changes after divergence from common ancestor. Major change is result from small changes accumulating.

Question 19

Punctuated Equilibrium

Answer 19

Long periods of stasis (no change) interrupted by periods of divergence. Most species will undergo greatest changes when they first diverge from common ancestor.

Question 20

Humans and Speciation

Answer 20

We cause allopatric speciation. Eg. builds infrastructures, floods land for dams, relocates individuals within a species