#15-Nature Of Communities

Question 1

What is a physically defined community?

Answer 1

Encompasses all species in an area

Question 2

What is a biological,y defined community?

Answer 2

All species associated with a region/ general area

- emphasis importance of abundant species

Question 3

3 ways to study organisms in a community

Answer 3

1. Taxonomic affinity- all of one species (ex:birds)
2. Guild- group of species that use the same resources
3. Functional group- species that functions in a similar way but don’t use the resource in the same way

Question 4

What is a food web?

Answer 4

Organizing species based on tropic or energetic interactions

Question 5

What is a downfall to food webs?

Answer 5

Doesn’t say much about the strength of the interactions I’d their importance in the community
- some organisms can feed on multiple levels

Question 6

What is an interaction web?

Answer 6

More accurately describes both the tropic (vertical) and non tropic (horizontal) interactions

Question 7

What is a community structure?

Answer 7

The number of species in a community

Question 8

What is species evenness?

Answer 8

Relative abundances compared with one another

Question 9

What is species diversity?

Answer 9

Combines species richness and species evenness

Question 10

What is the Shannon index?

Answer 10

Species diversity index

Sum of pi x ln(pi)

Question 11

What is biodiversity

Answer 11

Describes diversity at multiple spatial scale from genes to species to community

Question 12

What is genetic diversity?

Answer 12

Affects species in a community and the diversity of the species

Question 13

What are rank abundance curves?

Answer 13

Plot the proportional abundance of each species relative to others in rank order

• can tell if one is dominant over the other
• can tell if one is having a negative effect on the other

Question 14

What is species composition?

Answer 14

Identity of species in a community

Question 15

What is species accumulation curves?

Answer 15

Richness is plotter as a function of the total number of individuals that have been counted

Question 16

What are direct interactions?

Answer 16

Occur between 2 species

Question 17

What are indirect interactions?

Answer 17

Occur when the relationship between 2 species is mediated by a 3rd species

Question 18

How can we see indirect effects on s community?

Answer 18

When a species is removed

Question 19

What is a tropic cascade?

Answer 19

When one level is affected and the levels below are also impacted in a negative or positive way

Question 20

What is tropic facilitation?

Answer 20

Consumed is indirectly facilitated by a positive interaction between its prey and another species

Question 21

What is a competitive network?

Answer 21

Competitive interactions among multiple species in which every specie negatively interacts with every other species s

Question 22

What is interactions strength ?

Answer 22

Magnitude of the effect of one species on the abundance of another species

Question 23

What is a dominant/ foundation specie ?

Answer 23

Have large effects on other species and thus species diversity, by virtue of their considerable abundance of biomass

Question 24

What are ecosystem engineers?

Answer 24

They create and modify or maintain physical habitat for themselves and other species

Question 25

What is a keystone species?

Answer 25

They have strong effects because if their roles in the community

Question 26

What are communities?

Answer 26

Groups of interacting species that occur together at the same place and time