Chapter 19

Question 1

Regional species pool

Answer 1

absolute amount of species that could potentially be in a community prior to filtering

Question 2

Humans are vectors of invasive species

Answer 2

Some fish travel to regions they couldn’t normally reach because of ships of fish, Zebra mussel (Dreissena polymorpha) arrived in north america due to ballast tank traveling to the great lakes

Question 3

Biotic resistance

Answer 3

interactions of native species in a community with non native species that exclude or slow growth of non native species

Question 4

Resource partitioning

Answer 4

relies on ecological and evolutionary compromises that result in divergence in resources needed for coexistence

Question 5

Study on Warblers Robert MacArthur

Answer 5

Applying equilibrium theory of island biogeography to entire communities using warblers as a model. Recorded feeding habits, nesting locations, and breeding territories of five warbler species. Warblers coexist through distinct habitat utilization, varying nesting heights, and specific prey hunting regions; analysis using the Shannon index revealed a positive correlation between bird species diversity and foliage height diversity, emphasizing the significance of habitat structural complexity over tree species identity.

Question 6

Resource ratio hypothesis

Answer 6

species coexist by using resources in different ratios/proportions

Question 7

Example of resource ratio hypothesis

Answer 7

Experimented by growing diatom cyclotella and asterionella in a labaratory that differed in ratios of silica to phosphorus. When both ratios were limiting both species could coexist otherwise there was competition

Question 8

Intermediate disturbance hypothesis

Answer 8

explains how gradients in disturbance affect species diversity in communities

Question 9

Competitive displacement

Answer 9

occurs when the best competitor uses limiting resources that the weaker competitor requires causing a decline in the weaker competitors’ population growth

Question 10

Huston’s dynamic equilibrium model

Answer 10

considers how frequency or intensity of disturbance and rater of competitive displacement combine to determine species diversity

Question 11

Menge- Sutherland model

Answer 11

predicts predation should be important in maintaining species richness at low levels of stress/disturbance, allowing for predators to easily feed on competitively dominant species therefore reducing their abundance.

Question 12

Community functions

Answer 12

processes that control community structure and include not only disease suppression but also plant productivity, water quality and availability, atmospheric gas exchange, and resistance to disturbance

Question 13

Complementary hypothesis

Answer 13

proposes that as species richness increases, there will be a linear increase in community function

Question 14

Redundancy hypothesis

Answer 14

relies on assumptions similar to complementary hypothesis, but places an upper limit on effect of species richness on community function

Question 15

Idiosyncratic hypothesis

Answer 15

proposes that ecological functions of some species have strong effects than others do and that it varies dramatically

Question 16

Macarthur and Elton theorized that species richness

Answer 16

can be positively related to community stability, or when a community remains, returns, to its original strucuture and function after some perturbation

Question 17

Darwin’s species struggle for existence study

Answer 17

unmowed grass had dominant competitors that dominated weedy and cut plant species richness, whereas mowed grass did the opposite

Question 18

Hutchinson’s Plankton Coexistence Model

Answer 18

Explored coexistence in freshwater lake plankton by focusing on resource competition. Coexistence occurs when the time for competitive exclusion equals the time for environmental variation.

Question 19

Robert Paine’s Predator Impact on Mussel Community

Answer 19

Manipulated predatory sea star (Pisaster) densities affecting mussel species richness. Where Pisaster was present, species richness increased, supporting coexistence through predation.