L4: Global patterns of biodiversity

Question 1

Species richness

Answer 1

Number of species per unit area

Question 2

Endemic species

Answer 2

Pertaining to a taxon that is restricted to the geographic area specified, such as continent, lake, biome, or island.

Question 3

Cosmopolitan (or widespread species)

Answer 3

Occurring essentially worldwide, as on all habitable landmasses or in all major oceanic regions.

Question 4

Body size and Bergmann’s rule

Answer 4

Bergmann’s Rule (1847): Body size increases with latitude. Within a given group of organisms, those with larger body sizes will be found at higher latitudes.

Therefore, animals tend to be larger in cold areas than in tropical ones.

Question 5

What is Allen’s rule

For example…

Answer 5

Animals in colder climates have shorter appendages (ears) than their close relatives in warmer climates.

Lepus in north America show a decline in the length of their ears with decreasing temperature.

Question 6

Gloger’s rule of colour in species

Answer 6

•More darker forms tend to be found in more humid environments, e.g. near the equator. To avoid UV
•In cold environments the color of the species tend to be lighter. Easy to hide in snow.
Floral pigmentation patterns provide an example of Gloger’s rule in plants (Koski, 2015)

Question 7

Latitudinal gradients

Answer 7

Species diversity decreases with increasing latitude.

Increasing species diversity from the poles to the Equator.

Question 8

What is Rapoport’s rule?

Answer 8

(Rahbek, 1997)

Rapoport’s rule is an ecogeographical rule that states that latitudinal ranges of plants and animals are generally smaller at lower latitudes than at higher latitudes.

Question 9

Latitudinal gradients

How is species diversity affected by increasing latitude?

Answer 9

Species diversity decreases with increasing latitude.

Increasing species diversity from the poles to the Equator.

Question 10

What is endemism?

Answer 10

Endemism is the restriction of a species range to a circumscribed area.
Australia, for instance has the highest number of endemic mammal species.

Question 11

Effect of elevation on species diversity

Answer 11

Decrease in species diversity with increase in elevation.
The climate after a certain height is less suitable for majority of species.

(Vertaas and Grytnes, 2002).

Question 12

What are the main processes in shaping the pattern of non endemic species richness?

Answer 12

Dispersal
Climatic filtering along elevational gradients
Human land use

Question 13

What is Sclater’s classification of marine biogeographic regions?

Answer 13

The use of tracking seals to observe broad biogeographic regions.

Question 14

Why are environments complex?

Answer 14

The latitude and altitudinal differences vary in biomes (e.g snow/ice, tundra, evergreen forest, temperate forests)

Differences in an environmental parameter such as aridity, e.g going from rainforest to desert.

Question 15

What is a climograph?

Answer 15

Diagram quantifying some aspects of the relationship between climate and vegetation types.

Question 16

What other traits can be related to latitude, elevation and different environmental gradients?

Answer 16

Body size
Dispersal capacity
Colour

Question 17

What was the observed relationships between the percentage of Single Island Endemics and elevation?

Answer 17

Strong pattern of increasing number of endemic species on top of the mountains.

Steinbauer et al, 2016

Question 18

What did Nogue et al., 2013 find about the richness of non endemic species with increasing elevation?

Answer 18

Decreases

Question 19

What are the rules you need to remember?

Answer 19

Bergmann’s Rule: Body size increases with latitude

Allen’s rule: Animals in colder climates have shorter appendages (ears) than their close relatives in warmer climates.

Gloger’s rule: More darker forms tend to be found in more humid environments, e.g. near the equator. To avoid UV

Rapoport’s Rule: The idea that latitudinal ranges of plants and animals are smaller at lower latitudes than higher latitudes

Question 20

What is a sink habitat?

Answer 20

A habitat that is a net importer of individuals, because local reproduction is not sufficient to balance local mortality.