Community Ecology

Question 1

What does community ecology attempt to describe?

Answer 1

The distribution and abundance of species living in a local area

Question 2

How is regional diversity gained and lost?

Answer 2

Gained by immigration and speciation

Lost by mass extinctions and dispersal

Question 3

What creates local diversity?

Answer 3

Habitat selection by the individuals in the regional pool

Question 4

How is local diversity gained and lost?

Answer 4

Gained by habitat selection
Lost by drift, stochastic extinction
Selection by competition and predation also matters

Question 5

What determines the structure of a community?

Answer 5

Types of species, the number of species, the relative abundance of each species

Question 6

What will be present in a community?

Answer 6

Autotrophs, primary consumers, secondary consumers, tertiary consumers, detritivores, decomposers

Question 7

What determines if a species is considered to be abundant or rare?

Answer 7

Biomass, the area occupied, the number of individuals

Question 8

Why would one or a few species be dominant in a community?

Answer 8

Good at competition, low predation, aggressive behaviour

Question 9

What is diversity?

Answer 9

The number of species and their relative abundance

Question 10

What is species richness?

Answer 10

The number of species in a community

Question 11

What is species evenness?

Answer 11

The relative abundance and variation in a community

Question 12

What is the Shannon Weiner Diversity index?

Answer 12

A combination of species richness and the number of individuals per species. The number is meaningless unless compared

Question 13

When is diversity the highest?

Answer 13

When all species are equally abundant

Question 14

What does Simpson’s index tell us?

Answer 14

How likely it is to randomly choose two individuals that are exactly the same

Question 15

What is α-diversity?

Answer 15

Number of species in a habitat

Question 16

What is β-diversity?

Answer 16

Number of unique species between 2 habitats

Question 17

What causes a high β-diversity?

Answer 17

Different species in each new place, big change in the environment from place to place

Question 18

What is gamma-diversity?

Answer 18

Number of species in a region

Question 19

What determines diversity?

Answer 19

Physical structure of the environment, species interactions, and disturbances

Question 20

How does habitat heterogeneity relate to diversity?

Answer 20

Environment can support more species, have a heterogenous resource distribution, which minimizes competition and stops 1 species from becoming dominant

Question 21

What is species zonation?

Answer 21

Changes in the physical and biological structures of a community as the landscape changes

Question 22

How does zonation affect species?

Answer 22

Different survival rates, different reproduction rates, alters competition and tolerance

Question 23

How do species interactions influence diversity?

Answer 23

Realized niche, a species may be unable to tolerate the conditions because of interactions with other species

Question 24

Between abiotic conditions and biotic factors, which determines a) what species are present
b) which species are dominant or rare

Answer 24

a) abiotic conditions

b) biotic factors

Question 25

What is a disturbance?

Answer 25

A departure from average conditions for an area

Question 26

What are characteristics of a disturbance?

Answer 26

Relatively discrete event in time, disrupts an ecosystem, community, populations, physical environment, resource availability

Question 27

How can a disturbance increase diversity?

Answer 27

Can kill, damage, or displace individuals and creates opportunities for new individuals or species to come in

Question 28

What is the intermediate disturbance hypothesis?

Answer 28

Moderate levels of disturbance increase diversity

Question 29

How does too much disturbance or too little disturbance decrease diversity?

Answer 29

Too much: abiotic tolerances determines who lives there, or nothing can survive
Too little: lots of competition, has a dominant species

Question 30

Which intermediate disturbance levels, who can persist in the environment?

Answer 30

Good colonizers and good competitors