Competition and predation

Question 1

Competition

Answer 1

2 organisms use the same resource or seek that resource to the detriment of both

Question 2

Predation

Answer 2

one animal species eat all or a part of a second animal’s species

Question 3

Herbivory

Answer 3

One animal species eat all or part of a plant species

Question 4

Parasitism

Answer 4

2 species live in a physically close obligatory association in which the parasite depends metabolically on the host

Question 5

Disease

Answer 5

an association between a pathogenic microorganism and a host species in which the host suffers physiologically

Question 6

Mutualism

Answer 6

2 species live in close association with one another to the benefit of both

Question 7

Resource competition

Answer 7

when a number of organisms of the same or different species use common resources that are in short supply

Question 8

What is resource competition also known as?

Answer 8

scramble/exploitative competition

Question 9

Interference competition

Answer 9

occurs when the organisms seeking a resource harm one another in the process, even if teh resource is not in short supply

Question 10

Gause’s hypothesis

Answer 10

2 species displace each other which means each takes possession of certain foods and modes of life in which it has advantages over its competitor

Question 11

The Competitive exclusion principle (CCCC)

Answer 11

complete competition cannot coexist - Hardin 1960

Question 12

Realised Niche

Answer 12

Observed resource use of a species in the presence of competition

Question 13

How did Grinnell define the niche in 1917?

Answer 13

a subdivision of the habitat, each niche being occupied by one species

Question 14

How did Elton define the niche in 1927?

Answer 14

the role of a species in a community

Question 15

How did Hutchiinson define the niche in 1958

Answer 15

The n dimensional hypervolume or fundamental niche of teh species is the set of resources it can use in the absence of competition and other biotic interactions

Question 16

Name 3 times when competitive exclusion DOESNT occur in natural population

Answer 16

1) the environment is unstable and populations don’t reach equilibrium
2) resources are not limiting
3) the environment fluctuates such that the direction of competition reverses before extinction occurs

Question 17

Why is it that in stable environments, closely related species still live together?

Answer 17

• competition was always rare in nature

- competition has been common in nature, but species have adapted to avoid it

Question 18

Tern species on Christmas island, Pacific ocean

Answer 18

they partition food by collecting different sized fish

Question 19

Resource partitioning

Answer 19

when similar but different species use the same resource but use different parts of it evenly

Question 20

How common is competition according to Krebs 2002?

Answer 20

found in 218 studies, covering 93 species

Question 21

what could differences in resource use among closely related species be a by product of? (2)

Answer 21

• competition in the past

- speciation - i.e shift not due to competition

Question 22

describe the effects of limited similarity?

Answer 22

• limited overlap allows both species to coexist

- strong overlap drives one species to extinction to exploit a different range of resources

Question 23

Name one consequence of competition and the problem of this

Answer 23

species may diverge in some way where they occur together

- may reinforce reproductive barriers in closely related species

Question 24

Give an example of character displacement

Answer 24

beak sizes in Darwin’s finches on Galapagos

Question 25

What does the theory of k selection and r selection relate to?

Answer 25

Evolution of competitive ability

Question 26

What does k selection represent?

Answer 26

Resource competition

Question 27

What does R selection represent?

Answer 27

Colonization and growth

Question 28

What is the main difference between r selected and k selected animals in this theory?

Answer 28

- R selected animals rarely suffer from interspecific competition whereas k selected animals DO suffer regularly

Question 29

Do k selected or r selected animals use NO competitive ability?

Answer 29

R selected animals

Question 30

How is effect size calculated?

Answer 30

mean biomass of control group - mean biomass of the experimental group / standard deviation of both groups pooled

Question 31

What is character displacement?

Answer 31

when differences among similar species whose distributions overlap geographically are emphasised in areas where the species co occur, but are minimized where teh distributions don't overlap

Question 32

In Grime's triangle of plsnt life history strategies; the CSR model, what does CSR stand for?

Answer 32

C- competitive S - stress tolerant R - ruderal

Question 33

What does ruderal mean?

Answer 33

a plant growing on wasteland or rubbish e.g. a weed

Question 34

In what conditions do you find ruderal r strategy according to Grime's theory?

Answer 34

- High intensity of disturbace | - Low intensity of stress

Question 35

Name the 5 types of predator

Answer 35

- carnivore - herbivore - insect parasitoid lay eggs on host - plants/aniamls live on their hosts - cannibal

Question 36

What are the three main roles of predation?

Answer 36

- restricts distribution or reduce abundance of prey - affects organisation of a community - drivees natural selection and adaption

Question 37

What is the difference between competition and apparent competition?

Answer 37

competition involves 2 predators and one herbivore whereas apparent involves 2 predators and 2 herbivores (so no competition)

Question 38

What is the main difference between apparent and normal competition?

Answer 38

apparent; competition between prey drives the pattern | normal; competition through exploitation of a shared prey

Question 39

What is significant about the Skunks in North Dakota? (2)

Answer 39

if you remove skunks from wetlands, there is a bounce back in the nestlings of waterfowls - more duck eggs hatched when skunks were removed from waterfowl areas

Question 40

What is significant about dingos and red kangaroos in new south wales?

Answer 40

- where dingo numbers are controlled, red kangaroos increase

Question 41

Name the 4 components of predation?

Answer 41

1 - numerical response 2- functional response 3- aggregative response 4- developmental response

Question 42

Numerical response

Answer 42

where the density of predators in a given area increase by reproduction

Question 43

Functional response

Answer 43

where the number of prey eaten by individual predators changes, often with prey density

Question 44

Aggregative response

Answer 44

where individual predators move into and concentrate in the study area

Question 45

Developmental response

Answer 45

where individual predators eat more or less prey as predators grow towards maturity

Question 46

Total response

Answer 46

% of prey organisms eaten per unit time by the entire predator population, plotted against prey density

Question 47

Define competitive exclusion/ Gauses Law

Answer 47

the inevitable elimination from a habitat of one of two different species with identical needs for resources.