Ecosystems

Question 1

What is the definition of biodiversity?

Answer 1

The range of species within an ecosystem.

Question 2

What is the definition of species?

Answer 2

A group of organisms which can interbreed and produce fertile offspring.

Question 3

What is meant by population?

Answer 3

The total number of living organisms of one type (species) living in a habitat.

Question 4

What is meant by a habitat?

Answer 4

The place where an organism lives e.g. in water, in soil, trees etc.

Question 5

What is meant by a community?

Answer 5

All the organisms e.g. plants, animals and micro-organisms, that live in a particular area.

Question 6

What is meant by an ecosystem?

Answer 6

All the organisms (the community) living in a particular habitat and the non-living components with which the organisms interact.

sometimes written as community + habitat.

Question 7

Describe what is meant by a niche.

Answer 7

Every organism has its own niche. A niche is the role an organism plays within a community. It relates to the resources it requires in its ecosystem, such as light and nutrient availability and its interactions with other organisms in the community. It involves competition and predation and the conditions it can tolerate e.g. temperature.

Question 8

What is the definition for a niche?

Answer 8

The role an organism plays in the community.

Question 9

What is the definition for a producer?

Answer 9

An organism that can produce its own food. e.g. a plant

Question 10

What is the definition for a carnivore?

Answer 10

An animal which eats only animals.

Question 11

What is the definition for a consumer?

Answer 11

An animal which eats other organisms.

Question 12

What is the definition for a herbivore?

Answer 12

An animal which eats only plants.

Question 13

What is the definition of a predator?

Answer 13

An animal that hunts and eats other animals.

Question 14

What is the definition of prey.

Answer 14

An animal that is hunted and eaten by other animals.

Question 15

What is the definition of a decomposer?

Answer 15

An organism which feeds on dead organisms.

Question 16

What is the definition of an omnivore?

Answer 16

An animal which eats plants and animals.

Question 17

What is a food chain?

Answer 17

A food chain is a diagram which shows a simple feeding relationship between organisms.

Question 18

How is a food web made?

Answer 18

A series of interconnecting food chains make up a food web which shows the detailed feeding relationships between organisms (of different species) in an ecosystem.

Question 19

Do food chains exist in isolation?

Answer 19

Food chains rarely exist in isolation.

Question 20

What do the arrows in a food web represent?

Answer 20

The arrows in a food web point from the food to the feeder and represent the flow of energy from one organism to another.

Question 21

What do food webs always start with?

Answer 21

Food webs always start with a producer, this is a plant.

Question 22

What can disrupt a food web?

Answer 22

Food webs are delicately balanced and the removal of one organism (species) can affect all the other organisms (species) in the food web. Human activities such as hunting, fishing or using chemicals that cause pollution, can all disrupt a food web.

Question 23

When does competition in ecosystems occur?

Answer 23

Competition in ecosystems occurs when recources are in short supply e.g. food, light (plants), water, mates, habitat.

Question 24

What are the effects of competition?

Answer 24

The effects of competition include more individuals of the successful species surviving to reproduce, thus increasing the number of successful species. The less successful species may therefore decrease in number.

Question 25

What are the two forms of competition?

Answer 25

There are two forms of competition:

Intraspecific competition and interspecific competition.

Question 26

What is the definition of intraspecific competition?

Answer 26

Intraspecific competition occurs amongst individuals of the same species and is for all recources required.

Question 27

What is the definition of interspecific competition?

Answer 27

Inter specific competition occurs amongst individuals of different species for one or few of the resources they require.

Question 28

Which of the two forms of competition is more intense?

Answer 28

Intraspecific competition is more intense than interspecific competition.

Question 29

What is essential for different species of animals to exist together?

Answer 29

Different species of animals can only exist together without competing as long as their requirements are different.

Question 30

What are the two conditions which organisms can tolerate?

Answer 30

Temperature and pH

Question 31

Why does temperature affect an organism’s ability to reproduce?

Answer 31

Enzyme-controlled reactions can be affected by environmental temperature, especially if the organism does not maintain a constant body temperature.
Temperature also affects the concentration of dissolved oxygen in the water which affects the rate of respiration in aquatic organisms.

Question 32

Why does pH affect an organism’s ability to survive?

Answer 32

pH affects enzyme activity.