Combined Biology - 4.7

Question 1

What is an ecosystem?

Answer 1

The interaction of a community of living organisms (biotic) with the non-living (abiotic) parts of the environment

Question 2

What do organisms need to survive and reproduce?

Answer 2

A supply of materials from their surroundings and from other living organisms.

Question 3

What do plants compete for?

Answer 3

• Light and space
• Water and mineral ions from the soil

Question 4

What do animals compete for?

Answer 4

• Food
• Mates
• Territory

Question 5

Within a community what does each species depend on other species for?

Answer 5

Food, shelter, pollinations, seed dispersal etc…

Question 6

What happens if one species is removed from a community?

Answer 6

The whole community can be affected (known as interdependence)

Question 7

What is a stable community?

Answer 7

One where all the species and environmental factors are in balance so that population size remains fairly constant

Question 8

List abiotic (non-living) factors which can affect a community

Answer 8

• Light intensity
• Temperature
• Moisture levels
• Soil pH and mineral content
• Wind intensity and direction
• CO₂ levels for plants
• O₂ levels of aquatic animals

Question 9

List biotic (living) factors which can affect a community

Answer 9

• Availability of food
• New predators arriving
• New pathogens
• One species outcompeting another (so numbers are no longer sufficient to breed)

Question 10

What are adaptations?

Answer 10

Features of an organism enabling it to survive in the conditions in which it normally lives

Question 11

How can adaptations be characterised?

Answer 11

• Structural
• Behavioural
• Functional

Question 12

What are extremophiles and what examples of habitat may they live in?

Answer 12

Organisms which live in habitats which are extreme e.g. high temperature, pressure or salt concentration

Question 13

Bacteria living in deep sea vents would be classified as what?

Answer 13

Extremophiles

Question 14

For life on Earth, what are the producers of biomass?

Answer 14

Photosynthetic organisms

Question 15

How can feeding relationships in a community be represented?

Answer 15

In a food web.

Question 16

Describe a simple food chain.

Answer 16

Producers are eaten by primary consumers, which in turn may be eaten by secondary consumers and then tertiary consumers.

Question 17

What are predators?

Answer 17

Consumers that kill and eat other animals

Question 18

What are prey?

Answer 18

Animals eaten by consumers

Question 19

In a stable community, what may happen to the numbers of predators and prey?

Answer 19

It may rise and fall in cycles

Question 20

What happens to all materials in the living world?

Answer 20

They are recycled to provide the building blocks for future organisms

Question 21

What does the carbon cycle return to the atmosphere?

Answer 21

Carbon dioxide - which is then used by plants for photosynthesis.

Question 22

What does the water cycle provide

Answer 22

Fresh water for plants and animals on land, before draining into the seas (water is continuously evaporated and precipitated)

Question 23

What role do microorganisms provide in an ecosystem?

Answer 23

They cycle materials through an ecosystem by returning carbon to the atmosphere and mineral ions to the soil

Question 24

What is biodiversity?

Answer 24

The variety of all the different species of organisms on Earth (or within an ecosystem)

Question 25

What does a great biodiversity ensure?

Answer 25

The stability of ecosystems by reducing the dependence of one species on another for food, shelter and the maintenance of the physical environment

Question 26

What can impact biodiversity?

Answer 26

Waste, deforestation and global warming

Question 27

How are most human activities impacting biodiversity?

Answer 27

Human activities are reducing biodiversity (impacting the future of the human species)

Question 28

What does rapid growth in human population and increasing living standards lead to?

Answer 28

More resources are used and more waste produced (including pollution when not handled properly)

Question 29

Where can pollution occur?

Answer 29

* Water (sewage, fertilisers or toxic chemicals) * Air (smoke and acidic gases) * Land (landfill and toxic chemicals)

Question 30

What can pollution cause?

Answer 30

A reduction in biodiversity as plants and animals can be killed

Question 31

What are humans doing to the amount of land available for other organisms?

Answer 31

Reducing the available land: building, quarrying, farming and dumping waste

Question 32

What problems are associated with peat bog destruction (for use as garden compost)?

Answer 32

This habitat is reduced and thus the variety of different plant, animal and microorganisms (biodiversity) which live there

Question 33

What does the decay or burning of peat cause?

Answer 33

Carbon dioxide to be released: links to global warming

Question 34

Why has large scale deforestation in tropical areas occurred?

Answer 34

To provide land for cattle and rice fields / growing crops for biofuels

Question 35

What gases are contributing to global warming?

Answer 35

Carbon dioxide and methane

Question 36

What programmes are in place to reduce the negative effects of humans on ecosystems and biodiversity?

Answer 36

* Breeding programmes for endangered species * Protection / regeneration of rare habitats * Reintroduction of field margins * Reduction of deforestation and CO₂ emissions * Recycling resources rather