Chapter 54: Community Ecology II Flashcards Preview

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Flashcards in Chapter 54: Community Ecology II Deck (20)
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1

Community structure

- Defined by species diversity and trophic structure

2

Trophic structure

- Feeding relationships among organisms in a community

3

Food chain/web (def.)

Link trophic levels from producers to carnivores and track transfer of food energy

4

Why most chains are limited to five or fewer steps?

- Energetic hypothesis

5

Energetic hypothesis

- Length of food chains are limited because energy use is inefficient (about 10% of energy is transferred)

6

Community structure and composition are affected by what?

- Species may have impact on structure
- Interactions within community (trophic interactions)

7

Dominant species (por qué son dominante?)

- Species that are most abundant or that collectively have highest biomass
- Superior competitors(best at surviving under certain conditions)
- Most successful at avoiding predation

8

Keystone species (def.)

- Species that exert strong control on community by altering the physical environment

9

Ecosystem engineer

Organisms that have strong influence on community by altering the physical environment

10

Genetic engineer

Organism that has some control over genetic selection

11

Trophic cascades

- Indirect interactions between species
- Removing predator = more prey, less of the species upon which typical prey prey

12

Biomanipulation

- Utilization of indirect interactions to restore ecosystems

13

Disturbance

- Affects community structure
- Event that changes community composition by removing organisms or altering resource ability

14

Disturbance regime characterization criteria?

- When
- How large
- How often
- How severe
- Extremely disturbed: high frequency and high intensity

15

Importance of disturbance

- Allow species to populate again, restarts nutrient cycle I suppose?

16

Intermediate disturbance hypothesis

- Moderate levels of disturbance can create conditions that foster greater species diversity than low or high levels of disturbance

17

Ecological succession use?

- Bioremediation

18

Ecological succession

- Transitions in species composition of community after a disturbance
- Disturbed area is colonized by variety of species

19

Primary succession

- Occurs when environment in which substrate devoid of vegetation and other organisms usually lacking in soil is deposited

20

Secondary succession

- Begins in an area in which soil remains after disturbance