Lecture 22: Biogeography

Question 1

Biogeography

Answer 1

Study of the variation in species composition and diversity among geographic locations

Question 2

Species richness and composition tend to vary with _______

Answer 2

latititude

Question 3

Where has higher diversity?

Answer 3

Tropics

Question 4

Species richness and composition vary from ____ even where latitude is roughly similar

Answer 4

continent to continent

Question 5

3 Categories of Hypotheses for why tropics are so diverse?

Answer 5

Diversification rate
Diversification time
Productivity or carrying capacity

Question 6

Diversification rate Hypothesis

Answer 6

Species diversification rate is higher in the tropics (then temperate)

Tropics have larger land area more stable temperatures than temperate region

Question 7

Diversification rate Hypothesis: tropic as cradle, museum, or destination?

Answer 7

High speciation rates
Tropics are a cradle of diversity (tropics are where species tend to be born)

Question 8

Diversification time Hypothesis

Answer 8

Diversification rates are similar but evolutionary time is greater in the tropics

Tropics have spent much longer since their last glaciation allowing more time for diversification

Question 9

Diversification time Hypothesis: tropic as cradle, museum, or destination?

Answer 9

Low extinction rates
Tropics are museum of diversity; tropics tend to have old species that in other parts of the world would go extinct

Question 10

Productivity or carrying capacity Hypothesis

Answer 10

Higher productivity results in more abundant resources in the tropics

Without winter, growing seasons are twice as long
Plants are more productive
Trees are bigger and potentially provide more niches for other species

Question 11

Productivity or carrying capacity: tropic as cradle, museum, or destination?

Answer 11

High immigration rates
Tropics are destination
Place where species that originated in other places end up invading and accumulating

Question 12

Tropical vs extratropical taxa origin (all extant and extinct bivalves)

Answer 12

Increase taxa in tropics

Question 13

Extant bivalves show

Answer 13

present distribution of taxa of tropical origin

Question 14

As with most things in ecology, “diversity” is higher in tropics” is not an

Answer 14

absolute truth

Question 15

Major biogeographic patterns

Answer 15

Species richness and composition tend to vary with latitude (tropics have higher diversity)

Species richness and composition vary from continent to continent, even when latitude is roughly similar

The same community type of biome can vary in species and composition depending on its location on Earth

Question 16

Wallace identified 6 biogeographic regions using ___ and 6 regions roughly correspond to _____

Answer 16

distributions of terrestrial animals

Earth’s major tectonic plates

Question 17

Vicariance

Answer 17

The geographical
separation of a population, typically
by a physical barrier such as a
mountain range or river, resulting in
a pair of closely related species.

Question 18

Global species diversity

Answer 18

all species that are currently present on Earth

Question 19

Regional species diversity

Answer 19

all species with the
possibility of inhabiting the
local scale. Area connected
enough for dispersal of species
and roughly similar climate

Question 20

Local species diversity

Answer 20

area of interest,
where individuals are
interacting (think
ecological population
definition for many
competing species)

Question 21

Local community as result of many

Answer 21

filters

Question 22

To get from regional species pool to local community: filters in order include

Answer 22

Dispersal or immigration
Abiotic factors
Species interactions

Question 23

γ diversity

Answer 23

Regional species pool

Question 24

α diversity

Answer 24

Local diversity

Question 25

β diversity

Answer 25

Species turnover

Question 26

Species composition measures B diversity (species turnover) which is

Answer 26

the number of species that are lost + the number of species
gained by moving from one local community to the next.

= (αA – common species) + (αB -
common species)

Question 27

Equal regional richness to local richness

Answer 27

all species get everywhere

Question 28

Proportional change to regional richness

Answer 28

Regional control of species

Question 29

Asymptotic change to regional richness

Answer 29

Some carrying capacity for species, local control

Question 30

Species richness increases when we increase

Answer 30

scale of the sampling area

Question 31

Species area curve

Answer 31

The number of species increases with area sampled
Does not stop because you start to encompass other types of habitats

Question 32

z for species area curve between

Answer 32

.2 and .35

Question 33

bigger z value for species area curve means

Answer 33

greater the β diversity.

That is, if
the turnover is greater, the differences among local sites are
greater.