Ecology - Change in Communities Final

Question 1

What are some of the effects of increasing water temperatures on corals in the Indian Ocean?

Answer 1

high water temperatures driven by large-scale climate change have caused coral bleaching (loss of symbiotic algae)

Question 2

what is responsible for dissolving the skeletons of corals

Answer 2

increased ocean acidification

Question 3

In what ways might biotic agents of change lead to changes in community structure over time

Answer 3

Biotic interactions can result in replacement of one species with another
* Diseases can initiate community change by causing death or slow growth of a species
* Ecosystem engineers or keystone species can influence community change

Question 4

what kind of community is described as a plant community that does not allow for further colonization

Answer 4

closed community

Question 5

what is an open/ individualistic view of community organization

Answer 5

seeing the relationship of coexisting species as simply the results of similarities in their requirements and tolerances and partly the result of chance

Question 6

Under what conditions are the discontinuities between communities fairly well defined?

Answer 6

but usually they are found where there are sharp physical boundaries such as the aquatic -terrestrial transition

Question 7

who viewed the process of succession as organisms and the environment interacting to shape succession

Answer 7

Charles Elton

Question 8

How did Charles Elton view the process of succession?

Answer 8

organisms and the environment interact to shape succession

Question 9

what type of succession involves the serial replacements of species that occur as a result of changing geophysical and chemical forces, that is, they are driven by external forces

Answer 9

Allogenic succession

Question 10

what is an example of an allogenic succession

Answer 10

conversion of salt marshes into woodlands

Question 11

what type of succession occurs on newly exposed landforms, in the absence of gradually changing abiotic influences

Answer 11

autogenic succession

Question 12

what succession occurs in aquatic habitats
as lakes fill in with organic matter

Answer 12

hydrarch succession `

Question 13

what is the establishment and development of plant communities in newly formed habitats previously without plants is called primary succession

Answer 13

primary succession of allogenic successin

Question 14

what is an example of primary succession of allogenic succession

Answer 14

primary succession that occurs on exposed till left by glaciers in southeast alaska

Question 15

what is the return of an area to its natural vegetation following a major disturbance

Answer 15

secondary succession of allogenic succession

Question 16

where can a secondary succession of allogenic succession be seen

Answer 16

plowed fields in the eastern United States were abandoned by farmers moving west after the frontier was opened up in the 19th century that it has been called old field succession

Question 17

which type of autogenic succession can be seen without the use of plants

Answer 17

primary

Question 18

which type of autogenic succession already had plants involved

Answer 18

secondary

Question 19

What are the most common “pioneer organisms” in the process of primary succession and what is their role in this process

Answer 19

lichens

Question 20

What is the facilitation model of successional dynamics?

Answer 20

species replacement is facilitated by previous stages that make modifications in the abiotic environment

Question 21

What is the tolerance model of successional dynamics?

Answer 21

assumes earliest species modify the environment, but in neutral ways that neither benefit nor inhibit later species

Question 22

State the inhibition model of successional dynamics.

Answer 22

early species modify conditions in negative ways that hinder later successional species
* In this model, species replacement is inhibited by the residents until they are damaged or killed
* The only possibility for new growth/colonization in this successional sequence arises when a disturbance leads to dominating species being destroyed, damaged or removed!

Question 23

How does the replacement of species occur in the inhibition model of successional dynamics?

Answer 23

species replacement is inhibited by the residents until they are damaged or killed

Question 24

How did Sousa (1979) test the inhibition model of successional dynamics

Answer 24

algae growing on boulders in the intertidal zone of the California coast

Question 25

Explain Tilman’s resource-ration hypothesis of successional dynamics

Answer 25

remember also as a way in which species competing for the same resources may coexist) that places strong emphasis on the role of changing competitive abilities of plant species as conditions slowly change with time

Question 26

Why is the concept of scale important to ecological investigations?

Answer 26

the exact nature of a community is determined by the dynamic processes of deaths, replacements and micro-successions that a broad view might conceal