Community Ecology

Question 1

what is a community?

Answer 1

interacting populations at a particular location

Question 2

What is a community characterized by?

Answer 2

• species richness (number of species present)

- Primary productivity (amount of energy produced)

Question 3

What is a niche?

give examples

Answer 3

the total of all the ways an organism uses the resources of its environment
ie:space utilization, food consumption, temperature range, appropriate conditions for mating, requirements for moisture and more

Question 4

What is interspecific competition?

Answer 4

occurs when two species attempt to use the same resource and there is not enough resource to satisfy both
*there has to be a limited resource for competition to exist

Question 5

What is interference competition?

Answer 5

physical interaction over access to resources

Question 6

What is exploitive competition?

Answer 6

consuming the same resources

Question 7

What is a fundamental niche?

Answer 7

entire niche that a species is capable of using based on physiological tolerance limits and resource needs

Question 8

What is a realized niche?

Answer 8

actual set of environmental conditions, presence or abundance of other species, in which the species can establish a stable population

Question 9

Who was the man who did the classical study of barnacles?

Answer 9

J.H.Connells

Question 10

Can species with identical resource requirements coexist?

Answer 10

no

Question 11

sympatric lizards have developed_____________ to avoid direct competition

Answer 11

subdivided niche

Question 12

_______ is often seen in similar species that occupy the same geographic area. This results from what?

Answer 12

resource partitioning; natural selection

Question 13

What is character displacement

Answer 13

difference in morphology evident between sympatric species

Question 14

What is predation?

Answer 14

consuming of one organism by another

Question 15

True or False:

predation strongly influences prey populations?

Answer 15

true

Question 16

give an example of an animal that does chemical defense

Answer 16

monarch butterfly caterpillars feed on milkfeed and dogbane families and incorporate cardiac glycosides into their body

Question 17

Give two things that characterize defense of coloration

Answer 17

• poisonous animals use warning coloration

- organisms that lack chemical defencies are seldom brightly colored (camouflage or cryptic coloration)

Question 18

What does mimicry allow a species to do?

Answer 18

capitalize on defensive strategies of another

Question 19

What is Batesian mimicry?

Answer 19

mimics look like distasteful or predatory species

Question 20

What is Mullerian mimicry?

Answer 20

several unrelated but poisonous species come to resemble one another

Question 21

What is symbiosis?

Answer 21

2 or more organism interactions in a long-term association

Question 22

What are the three types of symbiosis?

Answer 22

Commensalism
Mutualism
Parasitism

Question 23

Describe commensalism

Answer 23

one organism benefits while the other isn’t harmed

Question 24

Describe Mutualism

Answer 24

both organisms benefit

Question 25

Describe Parasitism

Answer 25

one organism benefits while the other is harmed

Question 26

What are the two types of external parasites?

Answer 26

ectoparasites

parasitoids

Question 27

Describe Ectoparasites

Answer 27

Feed on exterior surface of an organism

Question 28

Describe parasitoids

Answer 28

insects that lay eggs on living hosts

ie: wasp

Question 29

The only type of internal parasites are endoparasites. Describe them

Answer 29

• live inside the host
• extreme specialization by the parasite as to which host it invades
• many parasites have complex life cycles involving more than one host

Question 30

describe taxoplasmosis

Question 31

Does predation reduce or increase competition

Answer 31

reduces

*look at slide 25

Question 32

What is an indirect effect of species interactions?

Answer 32

presence of one species may affect a second by way of interactions with a third species

Question 33

What are Keystone species?

Answer 33

species whose effects on the composition of communities are greater than one might expect based on their abundance

• Keystone species can manipulate the environment in ways that create new habitats for other species
  ie: Beavers

Question 34

Describe succession

Answer 34

communities have a tendency to change from simple to complex

Question 35

What is the difference between Primary and Secondary Succession?

Answer 35

primary succession occurs on bare, lifeless substrate (open water, rocks) while secondary succession occurs in areas where an existing community has been disturbed but organisms still remain (field-left uncultivated, forest after a fire)

Question 36

early successional species are characterized by ________

Answer 36

r-selected species

Question 37

What is facilitation?

Answer 37

early successional species introduce local changes in the habitat
(k-selected species replace r-selected)

Question 38

Communities are constantly changing due to what?

3 things

Answer 38

1. ) climate changes
2. ) species invasion
3. ) disturbance events

Question 39

nonequillibrium models that emphasize______ rather than____ are used to study communities and ecosystems

Answer 39

change; stability

Question 40

What is the intermediate disturbance hypothesis?

Answer 40

communities experiencing moderate amounts of disturbance will have higher levels of species richness than communities experiencing either little or great amounts of disturbance