Ecology and energy transfers (5.1–5.4, 5.10–5.11, 5.21)

Question 1

Ecosystem

Answer 1

All the organisms living in a particular area and all the non living (abiotic) factors

Question 2

Community

Answer 2

All of the organisms of different species that live in the same habitat and interact with each other.

Question 3

Population

Answer 3

All the organisms of one species in a habitat.

Question 4

Habitat

Answer 4

The place where an organisms lives.

Question 5

Why do abiotic factors impact abundance of species?

Answer 5

They impact if a species can grow fast and reproduce successfully.

Question 6

How does interspecific competition impact the abundance of species?

Answer 6

Interspecific competition when organisms of different species compete for the same resources.
Which means that the resources available to both populations are reduced. So the population will be limited.

Question 7

What is interspecific competition?

Answer 7

Competition between different species.

Question 8

What is intraspecific competition?

Answer 8

Competition within a species

Question 9

What is the maximum stable size of a population called?

Answer 9

Carrying capacity

Question 10

Why is prediation a biotic factor?

Answer 10

As population size of one changes so does the other.

Question 11

What is a niche?

Answer 11

The role of a species within its habitat.

Question 12

Define biotic factors and give an example.

Answer 12

Living features of an ecosystem eg predators and disease.

Question 13

Define abiotic factors and give an example.

Answer 13

Non living factors of an ecosystem eg light temp pH of water/soil.

Question 14

How do niches affect the abundance and distribution of organisms in a habitat?

Answer 14

No two species can occupy the same niche; interspecific competition excludes one species of the niche is divided according to adaptations.

Question 15

What is meant by primary succession?

Answer 15

Where an area previously devoid of life is colonised by a community of organisms.

Question 16

Summarise the process of primary succession.

Answer 16

1. Pioneer species can survive harsh conditions and colonise the area.
2. They change abiotic factors in their environment e.g. decomposition adds nutrients to the ground.
3. Over time more complex organisms survive and outcompete the initial species.

Question 17

What is a climax community?

Answer 17

Final seral stage of succession.

Ecosystem is stable in dynamic equilibrium over a long period of time.

Usually dominated by large trees or shrubs in rich soil.

Question 18

How might a species alter the environment that develops during succession?

Answer 18

• May improve environment to make it more suitable for other species.
• May worsen the environment by making it less suitable for other species.

Question 19

Define NPP

Answer 19

The rate at which energy from the sun is converted into the organic molecules that make up new plant biomass.

Question 20

Define GPP

Answer 20

The energy transferred to primary consumers.

Question 21

Give the mathematical relationship between GPP and NPP

Answer 21

NPP= GPP - plant respiration

Question 22

What is biomass?

Answer 22

Total dry mass of tissue or mass of carbon measured over a given time in a specific area.

Question 23

Units for biomass

Answer 23

Area= gm-2

volume= gm-3

Question 24

Why does biomass decrease at each trophic level?

Answer 24

1. Energy lost in nitrogenous waste (urine) and faeces.
2. Some of the organisms is not consumed
3. Energy lost to surroundings as heat.

Question 25

Give equation for % efficiency

Answer 25

energy converted to a useful form x 100 / total energy supplied

Question 26

How can knowledge of the carbon cycle be used to reduce atmospheric carbon dioxide levels?

Answer 26

Increase photosynthetic absorption of CO2 = reforestation

Reduce CO2 release = burn fewer fossil fuels