Ecosystems And Tropic Levels - Part 1 (T4)

Question 0

What is an ecosystem?

Answer 0

• an ecosystem is made up of all the living and non-living things in an area, for example farms and woods
• it is a distinct, self supporting system of organisms interacting with each other and with their physical environment
• it can be small in size, like a pond, or large like a swamp or a large forest

Question 1

No matter its size, what four components will an ecosystem generally have?

Answer 1

• producers: plants which photosynthesise and produce their own food
• consumers: animals that eat the plants or other animals
• decomposers: organisms which are responsible for the decay of dead material and so help to recycle nutrients
• physical environment: the total of the non-biological components of the ecosystem, for example in a pond this would be the water and soil while in the forest it would be the soil and air

Question 2

In each ecosystem a a range of habitats. What are these and give some examples…

Answer 2

• habitats are places where specific organisms live
• some are provided by the physical environment, for example in a pond the habitat of many of the plants is provided by the soil at the bottom of the pond and by the water
• other habitats are provided by the organisms themselves, for example dead vegetation provides a habitat for many decomposers

Question 3

All of the organisms of a particular species found in an ecosystem at any one time are known as the what?

Answer 3

The population of that species

Question 4

The populations of all the different species in an ecosystem are known as what?

Answer 4

A community

Question 5

How would an ecologist calculate how many organisms are present in a particular habitat?

Answer 5

The ecologist would count and analyse a representative part of the population, known as a sample

Question 6

What is a quadrat and how is it used?

Answer 6

• a simple piece of equipment that can be used by ecologists to gather a sample of plants of animals in an ecosystem
• it is usually made of metal, wood or plastic
• the suitable size depends on the size of the organisms being sampled
• the sampling must be random in order to provide a representative sample of the area

Question 7

Explain how organisms in an ecosystem continually interact with each other…

Answer 7

• feeding amongst organisms: plants, animals and decomposers are continually recycling the same nutrients through the ecosystem
• competition amongst organisms: animals compete for food, shelter, mates and nesting sites while plants compete for nutrients such as carbon dioxide, minerals and water
• numerous interactions between organisms and the environment: plants absorb minerals, carbon dioxide and water while returning water vapour and oxygen, and animals use materials from their environment to build shelters
• the temperature of the environment can also affect the processes occurring in organisms which can in turn affect the temperature of the environment as organisms release heat

Question 8

What organism does a food chain always start with?

Answer 8

A green plant (a producer)

Question 9

In a food chain, what is the animal that eats the producer called?

Answer 9

The primary consumer

Question 10

In a food chain, what is the animal that eats the animal that eats the producer called?

Answer 10

The secondary consumer

Question 11

What are the different stages in a food chain (eg: producer, primary consumer etc.) known as?

Answer 11

Tropic levels

Question 13

Describe a food chain that ends with salmon as the tertiary consumer…

Answer 13

Filamentous algae > mayfly nymph > caddis fly larvae > salmon