Biodiversity

Question 1

What is biodiversity?

Answer 1

The variety of all life at all levels in a given area

Question 2

What is a community?

Answer 2

Populations of interacting species and the abiotic factors in the given area

Question 3

What is an ecosystem?

Answer 3

Sum of communities and abiotic factors in a given area, often determined by climate. E.g. biome, landscape

Question 4

Is every species important?

Answer 4

The loss of any species can prevent the natural mechanisms of an ecosystem due to its fragility. The higher the biodiversity the more stable it is.

Question 5

Is extinction natural?

Answer 5

Yes, but the rate of extinction has been greatly increased by human interaction

Question 6

What are the 3 measurements of diversity?

What are the two combining factors?

Answer 6

Alpha, Beta and Gamma

Species Richness and Species Evenness

Question 7

Where is diversity highest?

Answer 7

Tropics where there is a high amount of environmental complexity (produces diversity), which are intermediately disturbed

Question 8

What is alpha diversity?

Answer 8

Within habitat diversity- species richness + species evenness (relative abundance)

Question 9

What is beta diversity?

Answer 9

Between habitat diversity / difference between habitats

Question 10

What is gamma diversity?

Answer 10

Total landscape diversity ( alpha * beta = gamma)

Question 11

What is species richness (R) ?

Answer 11

Total number of species in a given area, doesnt have to be species (can use higher rate of taxon).

Can compromise phylogenetic diversity (how similar are the species there)

Question 12

What is species evenness?

Answer 12

How abundant is each species in a given area. An area where one species dominates is less diverse than one where the species are equally abundant.

Question 13

What is the purpose of biodiversity indices and what are two examples?

Answer 13

To summarize the information collected about species richness and evenness.
Simpsons and Shannons

Question 14

How does Simpsons index work?

Answer 14

0 (highest) - 1 (lowest) diversity scores

Sum of (Proportion of each species in an area^2)

Question 15

How does Shannons index work?

Answer 15

0 (no diversity) upwards

Sum of( MINUS - proportion of species*( ln proportion of species)

Question 16

What is the problem with biodiversity indices?

Answer 16

Counter-intuitive results at extreme ends of the scale

Special forms of a general measure

Question 17

What is effective species number?

Answer 17

Equivalent number of species at maximum evenness.

Makes biodiversity indices comparable

Question 18

How do you get effective species number from biodiversity indicies

Answer 18

Simpsons: 1/ final result
Shannons: exponent( final result

Question 19

Describe some of the changes in biodiversity over time

Answer 19

Burst in diversification due to adaptations to environment
Overall increase in diversity over time 
Succession events 
Seasonal variation within species 
- migration
- hibernation

Question 20

Describe some the spatial patterns of biodiversity

Answer 20

Greater habitat variety –> greater species variety
Increased complexity –>greater species diversity
Species-Area Curve (larger area = more species)
High levels of endemism in isolated areas (islands)
Tropics more diverse than higher latitudes
Intermediate levels of disturbance promotes highest biodiversity.

Question 21

Why does intermediate disturbance lead to the highest rates of biodiversity?

Answer 21

Low disturbance- competition reduces diversity
Intermediate- time to colonize an area but not out-compete
High - little time for colonization due to random elimination

Question 22

Describe some other patterns in biodiversity?

Answer 22

Diversity declines as trophic level increase (food web cannot support many high end predators / few omnivores)
Most species are moderately abundant, not very or rare.

Question 23

What are biodiversity surveys and what is the point?

Answer 23

Build up knowledge of environment –> conservation
Requires: taxonomic knowledge, good observation, checklists, data collection, satellite images, GIS locations,

E.g. Bioblitz

Question 24

How do you estimate population size?

Answer 24

Mark and recapture

N1 (number caught in first bout)
N2 (number of individuals in second bout)
M2 (number of marked individuals in second bout)

(N1 x N2) / M2