Plate tectonics and development of earths biogeographic regions

Question 1

endemic

Answer 1

• taxon with a restricted geographic range

- e.g. koala bear endemic to Australia

Question 2

cosmopolitan

Answer 2

• broad geographic range

- e.g. rats/mice on all continents except Antarctica

Question 3

degree of endemicity

Answer 3

species > genera > families

Question 4

coefficient of similarity

Answer 4

quantitative estimate of degree of faunal/floral similarity between 2 regions

Question 5

coefficient of similarity = 1

Answer 5

flora/fauna of both regions is identical/in harmony

Question 6

coefficient of similarity = 0

Answer 6

there is no similarity of flora/fauna between the 2 regions

Question 7

why are higher taxonomic levels more cosmopolitan

Answer 7

• different species of a given genus occupy different environments
• long distance dispersal by one species by not others, expanding range of the genus
• evolution operates at species level
• new species: narrow endemics
• genus: cosmopolitan

Question 8

differences in endemicity due to

Answer 8

isolation, climate, ecological diversity

Question 9

beogeographic regions of mammal families

Answer 9

• Australia: isolated before placental mammals arrived
• N. &S. America: separate until formation of Panamanian isthmus
• S. America & Africa: separated in late Cretaceous & early Tertiary by Atlantic ocean
• Africa and Oriental: desert & mountain barriers in late Cenozoic

Question 10

Australia more forested in past

Answer 10

S. america and Australia have similar proportions of Arboreal genera

Question 11

flowering plant families

Answer 11

• only 56 plant families are endemic to 1 floral province (57% for mammals)
• flowering plants better at crossing ocean barriers
• 180 genera of flowering plants reaches Hawaii
• angiosperms evolved earlier than mammals and so dispersed globally when ocean barriers were smaller

Question 12

the higher the taxonomic rank

Answer 12

the higher the coefficient of similarity

Question 13

biogeographic regions of mammal families

Answer 13

• 51 of the 90 mammal families are endemic to only 1 fauna region
• most of the remainder restricted to 2 regions

Question 14

Biogeographic hierarchy

Answer 14

• biogeographic realms: several continents
• biogeographic regions: continental level
• biogeographic provinces: sub continental level
• divisions based on phylogentic relationships between plant/animal taxa