Deck 37: Animal Distributions

Question 1

What are some reasons why a species may be absent from a habitat or region to which it should adapt well

Answer 1

The reasons why a species may be absent from a region or habitat to which it should adapt well are:
• Extinction of the species in that region through hunting or other reasons
• The species is prevented from colonizing by other species
• There may be barriers to the spread or dispersal of the species
• Change in the previous habitat

Question 2

Define and distinguish the alternative explanations for disjunct distributions among animals: dispersal and vicariance.

Answer 2

Vicariance is the separation of a group of organisms by a geographic barrier, resulting in differentiation of the original group into new varieties or species. The geological events which produce such barriers are volcano, earthquakes etc.
Dispersal is the movement or expansion of a species into a new area from their places of origin. Animals move into favorable habitats that are geographically adjacent to their places of origin.
Dispersal occurs without the interference of nature while Vicariance occurs with the interference of nature.
In dispersal, the species migrate or move into better or favorable habitats on their own while in Vicariance the species are separated by force and may or may not be moved to a favorable location.

Question 3

Who first proposed the continental-drift theory What three sources of evidence convinced geologists that the theory was correct

Answer 3

Alfred Wegener first proposed the theory of continental drift in 1912.
The three sources of evidence which convinced geologists that the theory was correct are:
• Theory of plate tectonics which supported the hypothesis of drifting continents
• The presence of marsupials only in and
• The fact that temporary land bridges could serve as pathways for the dispersal of animals to other parts of the world

Question 4

How does continental-drift theory help to explain the disjunct distribution of marsupial mammals in Australia and South America

Question 5

What was the Great American Interchange When did it occur, and what were the results

Question 6

What are the consequences of climatic cycles for vicariance What difficulties do they introduce for the traditional methodology of vicariance biogeography

Question 7

How have the earth and life on it evolved together with each deeply influencing the other

Question 8

What is the biosphere How would you distinguish between the following subdivisions of the biosphere: lithosphere, hydrosphere, atmosphere

Question 9

What is the origin of oxygen on earth What would happen to earth's supply of oxygen if photosynthesis suddenly were to cease

Question 10

What is the evidence that increasing carbon dioxide levels in the atmosphere are responsible for an increase in the "greenhouse effect"

Question 11

What is a biome Briefly describe six examples of biomes.

Question 12

Describe three kinds of benthic marine communities that use hard substrates and three that use soft substrates. What are the main physical factors that separate community types within each substrate category

Question 13

What are some very productive marine environments, and why are they so productive

Question 14

What is the source of nutrients for animals living in the deep-sea habitat