Topic 2: The Ecosystem - Structure

Question 1

Distinguish between biotic and abiotic components of an ecosystem

Answer 1

The living parts of an ecosystem are called the biotic components and the non-living parts the abiotic components

Question 2

Define the term trophic level

Answer 2

The energy level that an organism occupies in a food chain

Question 3

Explain the principles of pyramids of numbers, pyramids of biomass and pyramids of productivity

Answer 3

PoN: This records the number of individuals at each trophic level

PoB: This represents the biological mass of each standing stock at each trophic level at a particular point in time

PoP: This shows the flow of energy (i.e. the rate at which the stock is being generated through each trophic level)

Question 4

Discuss how the pyramid structure affects the functioning of an ecosystem

Answer 4

Because energy is lost through food chains, top carnivores are at risk from disturbance further down the food chain.

Question 5

Define bioaccumulation

Answer 5

Bioaccumulation refers to the accumulation of substances, such as pesticides, or other organic chemicals in an organism.

Question 6

Define species

Answer 6

A particular type of organism. Individuals of this species can interbreed and produce fertile offspring

Question 7

Define population

Answer 7

A group of individuals of the same species living in the same area at the same time.

Question 8

Define habitat

Answer 8

The natural environment in which a species or a population of species lives and includes the physical environment

Question 9

Define niche

Answer 9

The position of an organism in its environment. Its habitat, resources obtained, time periods when active

Question 10

Define community

Answer 10

A group of populations living and interacting with each other in a common habitat

Question 11

Define ecosystem

Answer 11

A community of interdependent organisms and the physical environment which they inhibit

Question 12

Describe and explain population interactions (Competition, Predation, Parasitism, Mutualism)

Answer 12

Competition: When resources are limiting, populations are bound to compete for survival. No two species can occupy the same niche, so where niches overlap, competition exists.

Predation: When one animal or plant hunts another animal.

Parasitism: When one organism benefits at the expense of another

Mutualism: A symbiotic relationship in which both species benefit