Living with the physical environment

Section B: Living World

Ecosystems

What you need to know for your examination:a) An example of a small scale UK ecosystem to illustrate the concept of interrelationships within a natural

system, an understanding of producers, consumers, decomposers, food chain, food web and nutrient cycling.

b) The balance between components. The impact on the ecosystem of changing one component.c) An overview of the distribution and characteristics of large scale natural global ecosystems.

1. Read the statement below that explains what an ecosystem is. Underline/highlight the words you think are important in helping you remember this definition.

What is an ecosystem?

An ecosystem includes all of the biotic (living) components (things) in an area interacting with each other and also with their abiotic (non-living) environments.

2. a) Use two colours to complete the key.

Key:BIOTIC Living componentsABIOTIC Non-Living components

b) Use the key to show which components in the box below are living and which are non-living (never been alive).

Biotic or abiotic components?

Soil Plants Sun AnimalsBacteria Weather/climate Atmosphere Earth

3. Ecosystems can be a range of sizes. Put these ecosystems into size order in the table below:

Desert Puddle Hedge/pond Woodland

Scale (size) Ecosystem from the box above:Micro (smallest)Meso (medium)Macro (large)Biome (global/largest)

4. Click on the link below and answer the questions: http://www.bbc.co.uk/guides/z3c2xnb

a) What is a food chain?

b) What do food chains usually start with?

c) Where do plants get their energy?

1

d) Why are plants called producers?

e) Why are animals called consumers?

5. You need to be able to use a number of key terms in your examination. Find a definition for each of the following words (this link is the most useful): http://www.bbc.co.uk/schools/gcsebitesize/science/add_aqa_pre_2011/foodchains/foodchains1.shtml )

Key term Definition (meaning)Producers

Primary consumers

Secondary consumers

Scavengers

Decomposers

A freshwater pond ecosystem

2

6. Complete this key using 4 different colours:

Ecosystem key terms:Producers (gets its energy from the sun)Consumers (gets its energy from eating plants and animals)Scavengers (gets its energy from eating dead plants and animals)Decomposers (gets its energy from eating very small parts of dead plants/animals)

7. Read what each species in this pond ecosystem eats. Decide if it is a producer, consumer, scavenger or decomposer and then colour it the appropriate colour from your key.

8. What is a food web? http://www.bbc.co.uk/schools/gcsebitesize/science/21c/life_on_earth/species_interdependencerev2.shtml

9. Look at the food web of a freshwater pond ecosystem below. Highlight/write out at least one food chain you can see. Hint: always start food chains with producers (living things that use the sun for energy).

3

10. Using the food web above, describe what would happen if:

a) Disease wiped out dragonflies?Use this to help you:Biotic (living) components that would decrease are….

They would decrease because…..

Biotic (living) components that would increase are….

They would increase because…..

b) Humans added a zander fish (a fish that eats other fish)?Use this to help you:Biotic (living) components that would decrease are….

They would decrease because…..

Biotic (living) components that would increase are….

They would increase because…..

c) Humans clear the pond of weed to make it look nicer?

Use this to help you:Biotic (living) components that would decrease are….

They would decrease because…..

Biotic (living) components that would increase are….

They would increase because…..

Need help with Q10? Click here to see an example of a different food web:

http://www.bbc.co.uk/schools/gcsebitesize/science/21c/life_on_earth/species_interdependencerev2.shtml

Map to show the distribution of the world’s biomes (global ecosystems)

4

11. Use the map above to describe the location of each of the three biomes (global ecosystems).

a) Tropical rainforestsUse these questions to help you organise your answer:

Which line of latitude are they generally on? Which continents are they found in? Be specific; use compass directions or other key terms (e.g. coasts) to explain the location of tropical

rainforests in one of the continents.

DesertsUse these questions to help you organise your answer:

Which two lines of latitude are deserts generally found on? Which continents are they found in? Be specific; use compass directions or other key terms (e.g. coasts) to explain the location of deserts in one

of the continents.

Temperate deciduous forestsUse these questions to help you organise your answer:

Which continents are they found in? Be specific; use compass directions or other key terms (e.g. coasts) to explain the location of temperate

deciduous forests in one of the continents. We have temperate deciduous forests in the UK. Using your exercise book (or the internet), what line of

latitude are we on? Remember to say if it is north or south of the Equator.

5

Tropic of Cancer

Equator

Tropic of Capricorn

The characteristics of biomes (large scale natural global ecosystems): CLIMATE and SOILS

RAINFORESTS

12. Use the climate graph to describe the climates of rainforests.

a) Highest precipitation is ______mm

b) Lowest precipitation is ______mm

c) The most precipitation is found in the season _______________ (look up seasons here:http://www.foreignstudents.com/guide-to-britain/british-culture/weather/seasons)

d) The lowest temperature is _____˚c and the highest temperature is ____ ˚c. This is a ___________ (Small or large?)

range of ____ ˚c (subtract the smallest from the largest temperature).

6

13. Read the explanation of how the climate of a rainforest affects rainforest soils. Highlight/underline information you think is important for you to learn this information.

Rainforest soils are called LATOSOLS. Latosols are very deep (20 – 30 metres deep). At the top there is a thin black humus layer. The humus layer is the dark organic matter that forms in the soil

when plant and animal matter decays. Most of the nutrients in this soil are found in this top humus layer because dead leaves decay quickly in the

hot and humid conditions. The heavy rainfall dissolves and washes away these nutrients leaving an infertile soil. This is called leaching. The soil is a rusty orange colour because oxides of iron and aluminium remain in the soil after other minerals

have been washed out by leaching.

14. Use the information above to colour AND label a diagram of a latosol (rainforest soil). You can use the questions to help you.

DESERTS

15. Use the climate graph to describe the climates of rainforests.

a) Highest precipitation is ______mmb) Lowest precipitation is ______mmc) The least amount of precipitation is found in the season _______________ (look up seasons here:

http://www.foreignstudents.com/guide-to-britain/british-culture/weather/seasons)d) The lowest temperature is

_____˚c and the highest temperature is ____ ˚c. This is a ___________(Small or large?) range of ____ ˚c (subtract the smallest from the largest temperature).

7

Name of this layer?

Colour of this layer?

Depth? Is this layer fertile or infertile?

Colour of this layer?

16. Read the explanation of how the climate of a desert affects desert soils. Highlight/underline information you think is important for you to learn this information.

Desert soils tend to be sandy or stony with little organic matter (only a very thin humus layer at the top of this soil) because there is a lack of vegetation to drop their leaves.

It is very dry so vegetation that does drop to the floor does not rot very quickly. Any nutrients that do go into the soil are not leached (washed away) as there is so little rainfall.

Useful information:

TEMPERATE DECIDUOUS FORESTS

17. Match the climate feature with the correct description.

Climate feature Description for UK temperate deciduous forest

Precipitation Warm but not hot, about 17-18˚c

Summer temperatures Drier - usually 50 – 75mm per month.

Winter temperatures Cool but not cold, about 3-5˚c

Summer precipitation Wetter - usually around 20mm more than summer precipitation levels so 70 - 95mm per month.

Winter precipitation All year round.

8

18. Read the explanation of how the climate of temperate deciduous forests affects its soils. Highlight/underline information you think is important for you to learn this information.

Temperate deciduous soils are called brown earth soils. They are not as deep as latosols - 20-30 centimetres Brown earth soils have a deeper humus layer than latosols or desert soils because deciduous trees lose their

leaves in Autumn and then rot in the mild and wetter Winters. Some leaching does happen because of the wet climate but slower than the latosols. This means nutrients

are held in the soil so they are fairly fertile soils.

14. Use the information above to colour AND label a diagram of a brown earth soil. You can use the questions to help you.

9

Name of this layer?

Colour of this layer?

Depth? Is this layer fertile or infertile?

Colour of this layer?