Community Ecology

Question 1

Community

Answer 1

All the organisms that inhabit a particular area
Assemblage of populations of multiple species living close enough together for potential interactions

Question 2

Symbiosis

Answer 2

Interaction between two different species usually living in close physical association

Question 3

Inter specific interactions

Answer 3

Interactions with individuals of other species in the community

Question 4

Inter specific interaction examples

Answer 4

Competition
Predation
Her ivory
Parasitism
Mutualism
Commensalism

Question 5

A negative/negative interaction occurs when

Answer 5

Individuals of different species each use a resource that limits the fitness of both individuals

Question 6

Competitive exclusion

Answer 6

Two species cannot coexist permanently in a community if their niches are identical

Question 7

Exploitation

Answer 7

Any type of positive/negative interaction in which individuals of one species benefit by feeding in individuals if another species

Question 8

Exploration includes

Answer 8

Predation, parasitism, and herbivory

Question 9

Predation

Answer 9

One species kills and eats the other species

Question 10

Parasitism

Answer 10

One species gets nutrients from another organism which is thereby harmed

Question 11

Positive interactions

Answer 11

At least one individual benefits and neither is harmed

Question 12

Mutualism

Answer 12

Both species benefit from their interaction

Question 13

Commensalism

Answer 13

Interaction that benefits one species but neither harems or helps the other species

Question 14

Species diversity

Answer 14

The variety of different species in the community

Question 15

Species richness

Answer 15

Number of different species in the community

Question 16

Relative abundance

Answer 16

Proportion each species represents if all individuals in the community

Question 17

Caveats

Answer 17

Determining number and relative abundance of species jc challenging

Question 18

Why is determining the number of species challenging?

Answer 18

Most species in a community are rare
Difficult to get large sample size
Difficult to identify
Difficult to census
Microorganisms

Question 19

Community sustainability

Answer 19

Higher diversity communities are generally more productive and able to withstand and recover from environmental stressors

Question 20

Factors that affect community structure

Answer 20

1. Climate patterns
2. Geography
3. Heterogeneity (patchiness) of the environment
4. Frequency of disturbances or disruptive events
5. Interactions between organisms

Question 21

Trophic structure

Answer 21

Feeding relationship between organisms

Question 22

Food chain

Answer 22

Transfer of chemical energy from its source in primary producers to primary consumers to secondary and tertiary consumers and eventually decomposers

Question 23

Trophic level

Answer 23

Position an organism occupies in a food chain

Question 24

Foundation species

Answer 24

Have strong effect in communities as result of large size or high abundance
Ex trees, desert shrubs, kelp
Often provide habitat or food for members of the community

Question 25

Keystone species

Answer 25

Exert control on community structure NOT because of their abundance but because of their pivotal ecological role Ex sea stars

Question 26

Ecosystem Engineers

Answer 26

Species that create or dramatically alter their environment Change the physical environment and amount of resources available Ex beavers

Question 27

Bottom up control

Answer 27

Abundance of organisms at each Trophic label is limited by nutrient supply or food available at lower Trophic levels Controlled from the bottom of the food chain

Question 28

Top down control

Answer 28

Abundance of organisms at each Trophic level is controlled by the abundance of consumers at higher Trophic levels Controlled by the top of the food chain