Macroevolution

Question 1

What is meant by sympatric?

Answer 1

evolution of a new species from a surviving ancestral species, both in same geographic region

Question 2

What is meant by parapatric?

Answer 2

new species evolve in continuous yet spatially segregated habitats

Question 3

What is meant by peripatric?

Answer 3

speciation in which a new species is formed from an isolated peripheral population

Question 4

What is meant by sympatric?

Answer 4

geographic of vicariant speciation, biological populations have become geographically isolated (no gene flow)

Question 5

List some features of the hyracotherium

Answer 5

• earliest horse-like form
• only 3 hind toes and 4 distinct front toes
• teeth included flattened, grinding molars and pre-molars
• grasses rare in eocene and more common in miocene

Question 6

List some features of the miohippus

Answer 6

• late oligocene
• loss of the little digit and lateral digits reduced

Question 7

List some features of the merychippus

Answer 7

• arose in miocene
• premolars and molars are modern horse-like
• teeth long and high-crowned
• lengthened enamel ridges/hollows
• cement between ridges

Question 8

What selective forces shaped horse evolution?

Answer 8

• Grasses –> tough, apical meristem close to the ground
• teeth –> high-crowned due to wear against silica, deeper skull to aco0mmodate lengthened upper and lower teeth

Question 9

List some features of the coelacanth

Answer 9

• species persistance
• carniverous
• arose in devonian (>400mya)
• prevelant in triassic period
• believed extinct by late cretaceous

Question 10

Describe the arrival of cyanobacteria

Answer 10

• 2.6 bya
• oxygen released
• marks arrival of mass extinction

Question 11

What is the K-T event

Answer 11

• extinction of the dinosaurs, pterosaurs, pleisosaurs, mosasaurs, ammonites and belemnites
• likely due to impacts of meteorites and mantle plume eruption

Question 12

What caused the K-T mass extinctions

Answer 12

• short-term acid rain
• long-term atmospheric barrier to solar radiation

Question 13

What is the holocene extinction?

Answer 13

describes the ongoing extinction events of species due to human activity

Question 14

What is wallace’s line

Answer 14

imaginary line used to delineate faunas among islands

Question 15

List the effects of ice ages on faunas

Answer 15

1. extinction of species
2. formation of barriers to movement
3. splitting of populations and speciation

Question 16

What are the functions of Hox genes

Answer 16

• involved in embryogenesis
• control differentiation along the longitudinal body
• control differentiation of limbs along the axis