Biogeography L2

Question 1

What are the levels of organisation?

Answer 1

Species - Population - Communities - Ecosystems - Biosphere

Question 2

How many species currently exist?

Answer 2

3 million species have already been described

Only 1.5 million in any detail

Question 3

Species definitions:

What is the morphological (classical) species concept?

Answer 3

Morphological differences between species have an underlying genetic basis that is heritable

Question 4

What is a cryptic species? And give an example

Answer 4

Species within a genus that are morphologically so similar that they cannot be distinguished by superficial features (skipper butterflies)

Question 5

Species definitions: Biological species concept

Answer 5

Ernst Mayr - groups of populations that reproduce among themselves and not with other groups - offsprings fertile (difficult to identify reproductive isolation)

Question 6

Species definitions: Ecological species concept

Answer 6

Organisms must develop characteristics to out-compete others - defining ecological niche (misses cryptic species)

Question 7

What is a subspecies?

Answer 7

Well differentiated populations of genetically/morphologically distinct set of populations of a species (confined in area)

Question 8

What is a Polytypic species?

Answer 8

A specie that have a series of subspecies

Question 9

What is a Monotypic species?

Answer 9

specie that exists in just one form - no subspecies

Question 10

What is a population?

Answer 10

A group of organisms of the same species occupying a particular space at a particular time

Question 11

What did Malthus (1978) show about organism populations?

Answer 11

They have an inherent potential to increase their numbers exponentially

Question 12

What is the rate of change in population equation?

Answer 12

dN/dt=rN

Exponential

Question 13

What are the 6 limits to distribution?

Answer 13

Climatic - temp and precip 
Physical - high mountains
Geological - soil chem
Historical - changes in pattern overtime
Chance - arrivals
Biological - increased predation

Question 14

What is a niche?

Answer 14

Total requirements of a population or species for resources and physical conditions

Question 15

What is an ecological niche?

Answer 15

Environmental conditions where populations of a species can live/survive without the need to immigrate

Question 16

What is a one dimensional ecological niche?

Answer 16

Species with different, but overlapping requirements for a critical resource or habitat

Question 17

What is a ‘hypervolume’ of a two/multiple dimensional ecological niche?

Answer 17

Multiple species can coexist as all have unique niche space

Question 18

What is a fundamental niche?

Answer 18

A niche only occupied if limited by the environment and not by interactions with other species
No interspecific competition and predation

Question 19

What is a realised niche?

Answer 19

The observed ecological space a species uses - subset of entire fundamental niche

Question 20

What is inter-specific competition?

Answer 20

Different species share the same resource, one will eventually out-compete the other, affecting species diversity e.g. grey and red squirrels
(realised niche of red squirrel reduced)

Question 21

What is intra-specific competition?

Answer 21

Same species share same resources and leads to limitation of population size (seedlings may not grow under parent tree and competition for reproductive opportunities