Chapter 10 - Patterns in Species Richness

Question 1

What is species richness?

Answer 1

It refers to the number of species in a given area, but the practice of counting species is difficult

Question 2

What are diversity indices?

Answer 2

They are measures that combine both species richness and the evenness of the distribution of individuals among species.

ex. Shannon index
* DO PRACTICE QUESTIONS*

Question 3

What is evenness?

Answer 3

It is how even or equitably distributed species are. Is the abundance of all species equal? The more equal, the more diverse it will be

Question 4

What is niche breadth (n)?

Answer 4

It is the length of the portion of the resource continuum a species uses. The average is referred to as n-bar. Saturation occurs when there are a lot of different species using a resource continuum.

ex. the smaller n-bar is, the more specialized species will be accommodated for a given range of resources.

Question 5

What is niche overlap (o)?

Answer 5

It is when the niches of adjacent species overlap. The average is described by o-bar.

ex. the greater o-bar is, the more species there are that coexist on the resource continuum

Question 6

What is the productivity hypothesis?

Answer 6

It emphasizes the importance of climate in determining productivity at the lowest trophic level (plants/microbes) and the resources they provide herbivores, then carnivores

Question 7

What is the energy hypothesis?

Answer 7

It is alternative to the productivity hypothesis and emphasizes the direct role of energy on organisms throughout a community, measured by environmental temperature

Question 8

What is eutrophication?

Answer 8

It occurs when human activities lead to an increased input of nutrients (nitrates, phosphates, etc.) into waterways, like lakes, rivers, estuaries, etc.

Question 9

What is the paradox of enrichment?

Answer 9

It is when there is increased food available to the prey, which causes the predators population to destabilize.

ex. lots of food for rabbits makes them overabundant, so the pop grows unbounded, so then the lynx pop will grow unsustainably larger that will eventually result in a crash that could lead to extinction

Question 10

What is particulate organic carbon (POC)?

Answer 10

It is the rain of chemical energy falling as dead organic matter from the sea surface ???

Question 11

How does productivity influence species richness? How is this variation accounted for?

Answer 11

The increase in productivity can lead to an increased or decreased species richness, or both, or neither. This variation is accounted for through:

1. alpha-diversity
2. beta-diversity
3. gamma-diversity

Question 12

What is alpha-diversity?

REVIEW QUESTIONS

Answer 12

It refers to diversity at the local scale (within a community), so it is high when there are many species

Question 13

What is beta-diversity?

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Answer 13

It refers to the differences among communities within a region, so it is high when different communities in a region differ in the species they contain (found by dividing gamma by the average of alpha)

Question 14

What is gamma-diversity?

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Answer 14

It refers to diversity at a whole, regional scale (collection of communities), so it combines alpha and beta diversity and is highest when both individual communities are diverse/communities in the region differ. (found by adding the alpha diversity of all communities together)

Question 15

What is potential evapotranspiration (PET)?

Answer 15

It is the amount of water that would evaporate or be transpired from a saturated surface and therefore measures atmospheric energy

Question 16

What is net primary productivity (NPP)?

Answer 16

It is GPP-RES where gross primary productivity is the total rate at which ecosystems capture and store carbon as plant biomass and RES is plant respiration that releases some of the carbon

Question 17

What does benthic mean?

Answer 17

It means bottom-dwelling.

ex. species richness of benthic invertebrates are lower in more acidic streams

Question 18

What is the intermediate disturbance hypothesis?

Answer 18

It is when communities are expected to contain the most species when the frequency of disturbance is neither too high nor too low. Some species can tolerate low disturbance (K-selected) and others can tolerate high disturbance (r-selected).

look at predictors of richness table - ch 10

Question 19

What is a species-area relationship?

Answer 19

It is when both factors (species and area) depend on each other (island biogeography). Higher elevations will have more diversity (easier for flying species to land on).

ex. the number of species on an island decreases as the island area decreases

Question 20

What is species turnover?

Answer 20

It refers to some species being locally extinct and others immigrating

Question 21

What is a latitudinal gradient?

Answer 21

It refers to higher diversity occurring towards the equator that makes biodiversity hotspots with high richness and many endemic species

Question 22

What is the equilibrium theory of island biogeography?

Answer 22

It refers to the number of species being constant when the rate of immigration and extinction is equal.

look at graphs in notes