Competition

Question 1

Define competition.

Answer 1

An interaction brought about by a shared requirement for a resource in limited supply.

Question 2

Define a resource.

Answer 2

Something that may be used up or consumed. Can be renewable or unrenewable.

Question 3

Define scramble/exploitative competition.

Answer 3

Indirect competition. Approximately equal resource division.

Question 4

Define interference/contest competition.

Answer 4

Direct competition. Resource division can vary greatly.

Question 5

Define apparent competition.

Answer 5

Competition between 2 organisms not mediated by a resource. For example a shared parasite/predator.

Question 6

How do scramble competition and interference competition impact population dynamics?

Answer 6

Scramble competition causes boom-bust dynamics. Interference competition causes population stability.

Question 7

What are some proximate effects of competition?

Answer 7

Lost food/mates/territory.

Question 8

What are some ultimate effects of competition?

Answer 8

Reduced fecundity and survivorship.

Question 9

Does intraspecific or interspecific competition result in extinction of a species?

Answer 9

Interspecific competition.

Question 10

What are the 3 options for competing?

Answer 10

Move/Migrate, adapt or die (not recommended.

Question 11

Define self-thinning.

Answer 11

Progressive decline in density but an increase in biomass of the remaining individuals.

Question 12

What do plants compete for above ground?

Answer 12

Light, CO2, favourable temperatures and pollinators.

Question 13

What do plants compete for below ground?

Answer 13

Minerals, nutrients and water.

Question 14

What wavelength of light is used in photosynthesis?

Answer 14

400-700nm - Photosynthetically Active Radiation (PAR).

Question 15

What % of PAR is reflected?

Answer 15

10%

Question 16

What % of PAR is absorbed by the canopy?

Answer 16

79%

Question 17

What % of PAR is absorbed by the middle layer?

Answer 17

7%

Question 18

What % of PAR is absorbed by low vegetation?

Answer 18

2%

Question 19

What % of PAR reaches the forest floor?

Answer 19

2%

Question 20

What is the function of phytochromes?

Answer 20

They detect the ratio of red to far-red light and signal this to the plant.

Question 21

What are the 2 responses to shading?

Answer 21

Shade avoidance and shade tolerance.

Question 22

What are the signs of Shade Avoidance Syndrome (SAS)?

Answer 22

Delayed germination.
Stem elongation.
Petiole elongation.
Narrow leaves.
Early flowering.

Question 23

What are the signs of shade tolerance?

Answer 23

Increasing leaf area.
Orientating leaves to intercept light.
Reducing leaf overlap.
High chlorophyll b content.

Question 24

Does above or below ground competition impact plants more?

Answer 24

Below ground competition.

Question 25

What is kin recognition in plants?

Answer 25

Roots of kin plants are less likely to be influenced by a neighbouring plant.

Question 26

Define antibiosis.

Answer 26

An interaction where 1 participant is unaffected or benefits whilst the other is harmed by a toxin released by the first.

Question 27

Define ammensalism.

Answer 27

An interaction where 1 participant is harmed and the other is unaffected.

Question 28

Define allelopathy.

Answer 28

Direct or indirect inhibition by a plant producing chemicals.

Question 29

Define allelochemicals.

Answer 29

Secondary compounds of plant origin that interact with their environment and possess allelopathic properties.

Question 30

What is true type allelopathy?

Answer 30

Toxic compounds are released into the environment in the form they are produced in.

Question 31

What is functional type allelopathy?

Answer 31

Substances are released into the environment that becomes toxic due to microorganism transformation.

Question 32

What are the 4 mechanisms of allelopathy release?

Answer 32

Volatilisation, leaching, exudation and decomposition.

Question 33

What are some methods of 'attack' and 'defence' in fungi?

Answer 33

Antagonism, hyphal interference, mycoparasitism and gross mycelial contact.

Question 34

What does antagonism involve?

Answer 34

Upregulation of enzymes, the C + N metabolism and stress mitigation metabolites.

Question 35

What are the 4 outcomes of fungal interactions?

Answer 35

Deadlock, replacement, partial replacement and mutual replacement.

Question 36

What impacts fungal interaction outcomes?

Answer 36

Venue, microclimate, resource quantity/quality, other microorganisms and invertebrate grazing.

Question 37

What are bacterivores?

Answer 37

Fungi that utilise bacteria as a major nitrogen source.

Question 38

What is Gause's principle?

Answer 38

“Two or more species having identical patterns of resource use cannot coexist. One species will be better adapted and will out-compete the other”