Option : Ecology

Question 1

Define limiting factor.

Answer 1

A factor that affects the distribution of a species.

Question 2

Define characteristics of a species.

Answer 2

A range of factors tolerated by a species.

Question 3

Define mutualism.

Answer 3

An relationship between organisms of 2 different species in which each member benefits.

Question 4

Define parasitism.

Answer 4

A symbiotic relationship where the parasite gains an advantage to the detriment of the host which may be killed.

Question 5

Define commensalism.

Answer 5

A relationship where one organism benefits and the other is neither harmed nor helped.

Question 6

Explain the niche concept.

Answer 6

Each species plays a unique role within a community because of the unique combination of its spatial habitat and interactions with other species.

Question 7

Define a niche.

Answer 7

The specialised habitat of an organism. Includes territory, nutrition & feeding habits, reproductive habits, interactions with other organisms, role in habitat.

Question 8

Define intra-specific competition.

Answer 8

Competition between members of the same species.

Question 9

Define inter-specific competition.

Answer 9

Competition between 2 different species who rely on the same resources.

Question 10

Define keystone species.

Answer 10

A species which has a disproportionate effect on the structure of an ecological community.

Question 11

Define feed conversion ratios.

Answer 11

The quantity of dietary input in grams required to produce a certain amount of body mass in livestock or fish.

Question 12

Define gross production.

Answer 12

The total amount of organic matter produced per unit area per unit time by a trophic level in an ecosystem.

Question 13

Define net production.

Answer 13

The amount of gross production remaining after subtraction of the amount used for respiration by the trophic level.

Question 14

What do diameter of sink and thickness of arrow show in Gersmehl diagrams?

Answer 14

Diameter of sink is proportional to mass of nutrient stored in sink.
Thickness of arrow is proportional to rate of nutrient flow.

Question 15

Define biome.

Answer 15

A geographical area that has a particular climate and sustains a specific community of plants and animals.

Question 16

Define biosphere.

Answer 16

The total of all areas where living things are found.

Question 17

Define ecological succession.

Answer 17

The predictable and orderly changes in composition of an ecosystem over time.

Question 18

Define primary succession.

Answer 18

The emergence of a new community from a new ecosystem.

Question 19

Define secondary succession.

Answer 19

The replacement of one ecosystem by another following environmental change.

Question 20

Define closed ecosystems.

Answer 20

Ecosystems where energy but not matter is exchanged with surroundings.

Question 21

Define open ecosystems.

Answer 21

Ecosystems where matter and energy are exchanged with surroundings.

Question 22

Define alien species.

Answer 22

A species which arrives in a non-native habitat, usually as the intentional or accidental result of human activity.

Question 23

Define endemic species.

Answer 23

Species native to an area.

Question 24

Define bioaccumulation.

Answer 24

When an individual eats contaminated food or filters contaminated water, it builds up these chemical substances. This occurs within ONE trophic level.

Question 25

Define biomagnification.

Answer 25

A process by which chemical substances become more concentrated at each trophic level.

Question 26

Define indicator species.

Answer 26

An organism that occurs only when specific environmental conditions are present.

Question 27

Define biotic index.

Answer 27

Index that compares the relative frequency of an indicator species.

Question 28

Define in situ conservation.

Answer 28

A type of conservation that requires active management of nature reserves or national parks.

Question 29

Define ex situ conservation.

Answer 29

The preservation of species outside their natural habitat.

Question 30

Define competitive exclusion principle.

Answer 30

2 species that occupy a similar niche in the same location cannot coexist.