KS3 Bio 8D TEST 37Marks Ecological Relationships & Adaption

KS3 Bio 8D TEST 37marks Ecological Relationships & Adaption

Q1. A food chain found in the sea is:

Diatoms are producers. They are found very near the surface of the sea.

(i) Where in the sea would you expect to find copepods?

Tick the correct box.

usually in the top 5 metres of the sea

usually below 10 metres

usually below 50 metres

usually below 200 metres

1 mark

(ii) Explain your answer.

...... [1 mark]

Q2. In the left-hand column there are descriptions of four food chains.In the right-hand column there are four pyramids of numbers which are not drawn to scale. Draw a line from each description to the correct pyramid of numbers.

4 marks

Q3. (a) Scientists studied the animals and plants in a large wood, over a period of time. One food chain in the wood is shown below.

oak trees winter moth caterpillars great tits sparrowhawks

In the space below, draw a pyramid of numbers for this food chain.

2marks

(b) Insecticide was sprayed onto fields near the wood. Some of the insecticide was blown into the wood by the wind.

(i) In the food chain above, the sparrowhawks contained the highest concentration of insecticide. Explain why.

......

...... [2 mark]

(ii) The use of insecticides could cause the population of sparrowhawks to decrease.Give one other reason why the population of sparrowhawks might decrease.

...... [1 mark]

Adapted from Wytham Woods by Dr C M Perrins, published in The Biologist, Volume 36, 1989

(i) Use the graph to suggest the year when there were probably fewest sparrowhawks in the wood.

......

What is the evidence from the graph for your answer?

...... [1 mark]

(ii) Explain the reasoning for the answer you have given in part (c) (i).

...... [1 mark]

Q4. Scientists measured the concentration of the insecticide, DDT, in three animals and a microscopic plant called chlamydomonas.

(a) The food chain for these four organisms is shown below.

not to scale

(i)In the space below, draw the pyramid of numbers for this food chain. Write the name of the correct organism next to each section of the pyramid.

1 mark

(ii) The bar chart shows the concentration of DDT in the four organisms.

Give one reason for the difference in the concentration of DDT in these organisms.

...... [1 mark]

(b) In 1970 the average concentration of DDT in the tissues of sea lions in California was 760 parts per million. Nearly half the sea lion pups born in that year died because of high levels of DDT in their tissues.

How does DDT get from the body of a mother sea lion into the body of her pup:

(i)before the pup is born?

...... [1 mark]

(ii)after the pup is born?

...... [1 mark]

Q5. An ecosphere is a model habitat that can last for many years.The ecosphere below is a sealed glass ball containing sea water,green algae, bacteria, a snail and shrimps.

not to scale

(a) The ecosphere must receive plenty of light.

Explain why light is necessary for the survival of the green algae and the animalsin the ecosphere.

......

3 marks

(b) When organisms in the ecosphere die, they are broken down by bacteria.Nutrients, such as nitrates, are released back into the ecosphere.

Why is this necessary for the survival of the other organisms in the ecosphere?

...... [1 mark]

temperature of thewater (°C) / mass of oxygen dissolved(mg/100 cm3)
15 / 10.2
17 / 9.7
19 / 9.3
21 / 9.0
23 / 8.7
25 / 8.4
27 / 8.1
29 / 7.9

This ecosphere was kept at a temperature between 17°C and 23°C.

In this ecosphere, respiration in the organisms is affected less if the temperaturefalls to 15°C than if it rises to 27°C.Use information in the table to explain this.

...... [1 mark]

The water snake Natrixsipedonlives on small islands in Lake Erie in North America and on the nearby mainland.

The colour pattern on the body of the snakes is inherited. There are three body patterns.

A survey of the snakes on the islands gave the following results:

(a) (i) Which body pattern seems to improve the chances of survival toadulthood?

...... [1 mark]

(ii) Explain how camouflage helps snakes to survive.

...... [1 mark]

There is much more vegetation on the mainland than on the islands.Most of the snakes on the mainland are strongly banded.

Snakes from the mainland interbreed with snakes on the islands.

(b) (i) Suggest how the proportions of strongly banded and unbanded snakes on the islands would change over a number of years if this interbreeding stopped.

...... [1 mark]

(ii) Explain your answer with reference to the genes for body pattern.

......

...... [2 mark]

Q7. Bats hibernate during the winter. While they are hibernating, their hearts beat more slowlyandthey go into a deep sleep.

(a) Towards the end of the summer, bats build up a store of fat in a layer beneath the skin.Give one reason why fat is a useful storage substance.

...... [1 mark]

(b) While bats are hibernating their body temperature falls.What is the advantage of having a low body temperature during the winter?

...... [1 mark]

(d) Sometimes bats wake up too early from hibernation.These bats are unlikely to survive the cold weather.Give one reason for their low survival rate as a result of waking too early.

...... [1 mark]

Q8. The drawings show five different mammals. They are not drawn to scale.

(a) Which fact is only true about mammals but not true about other animals?Tick the correct box.

They can swim. / / They have four legs. /
They lay eggs. / / They produce milk tofeed their young. /

1 mark

(b) Look at the drawing of the bat.In what way are bats unusual mammals?

...... [1 mark]

(d) The porcupine has spines.How do the spines help a porcupine to survive?

...... [1 mark]

(e) In winter, the fur of the Arctic hare and the Arctic fox becomes thicker and turns white.

(i) How does thick fur help an Arctic hare and an Arctic fox to survive during the winter?

...... [1 mark]

(ii) The Arctic fox hunts and eats Arctic hares.How does white fur help Arctic hares to survive in the snow?

...... [1 mark]

Mark Scheme

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M1. (i) usually in the top 5 metres of the sea

if more than one box is ticked award no mark

the answer should imply proximity to their food source 1

(ii) because that is where the copepods’ food is or diatoms are

accept ‘because they feed on diatoms’do not accept ‘because they stay near the surface of the sea’

1[2]

M2. award one mark for each correct line if more than one line has been drawnfrom anydescription, award no mark for any of the lines from that description

4 (L7)

[4]

M3. (a)

one mark should be awarded if the secondlayer is wider than the first

the second mark should be awarded if thetop three layers gradually reduce in width

2 (L7)

(b) (i) any two from

•sparrowhawks eat great tits which contain insecticide

• great tits eat insects which contain insecticide

• a sparrowhawk eats lots of great titsor each great tit eats lots of caterpillars

• the insecticide is concentrated at each level in the food chain

• insecticide is not easily eliminated from an animal’s bodyor sparrowhawk’s body

• the insecticide is persistent

2 (L7)

(ii) any one from:disease,climate change; lack of food or water;reduced habitat; fewer great tits

accept ‘new predators’

accept ‘increase in predators’

1 (L6)

(c)either

(i) 1961 because the number of great tits was highest

accept ‘1960’ or ‘1962’ for 1961both the date and the evidence are required for the mark

1 (L6)

(ii) fewest great tits were eaten

1 (L7)

(i) 1976 because the number of great tits was lowest

accept ‘1975’ or ‘1977’ for 1976both the date and the evidence are required for the mark

1 (L6)

(ii) not enough food for the sparrowhawks

1 (L7)[7]

M4. (a) (i)

four boxes must be drawn, decreasing in width towards the top,and all labels must be correct for the mark

1 (L7)

(ii) any one from

• each animal eats lots of the organism below it in the food chain

accept ‘DDT increases up the food chain’

accept ‘the heron gets all the DDT in the other animals’accept ‘the heron is at the top of the food chain’

• DDT is not easily excreted

accept ‘DDT is not excreted’

• DDT is not broken down

accept ‘DDT remains in the body’accept ‘DDT is stored in the body’

1 (L7)

(b) (i) through the placenta

accept ‘through the umbilical cord’

accept ‘from the mother’s blood’

1 (L7)

(ii)in milk accept ‘through the mammary glands’

accept ‘the mother breastfeeds the pup’accept ‘the mother feeds the pup herself’

‘the mother feeds the pup’ is insufficient

1 (L7)[4]

M5. (a) any three from

• plants or algae need light for photosynthesis

accept ‘for photosynthesis’

• photosynthesis or algae or plants supply or produce oxygen

• plants or animals need oxygen

accept ‘oxygen is used for respiration’

• photosynthesis supplies glucose or carbohydrate or biomass

accept ‘glucose is a source of energy for the plant’

accept ‘the herbivores eat the plants’ or ‘animals eat plants’or ‘snails eat plants’

• carbon dioxide is produced by plants or animals

3 (L7)

(b) any one from:materials can be recycled; makes nutrients available; makes minerals available

1 (L7)

• at 27°C the oxygen concentration would drop too low

accept ‘the higher the temperature the less oxygen is dissolved’

accept ‘at a higher temperature they would suffocate’

• at 15°C there is more oxygen

accept ‘the lower the temperature the more oxygen there is’

‘there would be more oxygen’ is insufficient

1 (L6)[5]

M6. (a) (i)unbanded 1

(ii)a reference to predators or prey is required for the mark

they are less visible to predators orless visible to prey

accept ‘can hide from’ for ‘less visible to’ donot accept ‘less visible against rocks’

(b) (i) proportion of strongly banded snakes would decreaseorproportion of unbanded snakes would increase

accept ‘fewer strongly banded’ or ‘more unbandedsnakes’

(ii) the unbanded snakes are more likely to survive to breed

accept ‘strongly banded snakes are less likely to surviveto breed’

genes for the unbanded pattern are inherited by higherproportion of the offspring

accept ‘gene pool on island would contain a higher proportionof unbanded genes or a lower proportion of banded genes’

1[5]

M7. (a) any one from

• it is a good source or store of energy

do not accept ‘it is a good store of food’

do not accept ‘it is a source of energy’

• it insulates the body

accept ‘it keeps the heat in’

accept ‘it stops them getting too cold’

do not accept ‘it keeps the body warm’

• it is insoluble

1 (L6)

(b) any one from: less heat loss,less energy needed; food reserves or fat lasts longer 1 (L7)

• predators can catch them easily

• habitat or roosts could be damaged

• the food reserve may run out

1 (L7)

(d) any one from

• food in short supply

accept ‘no food’

• they lose too much heat

1 (L7)[4]

M8. (a) They produce milk to feed their young.

if more than one box is ticked, award no mark

1 (L4)

(b) any one from:they can fly, they have wings

1 (L3)

• it is streamlined

accept ‘its fur is smooth or fine or slopes backwards’

• its limbs are like fins or paddles

accept ‘it does not have legs’accept ‘it has flippers’

• it has a wide or powerful tail

‘it can swim’ is insufficient

1 (L4)

(d) any one from

• they protect it against predators

accept ‘they protect it’

• they make it difficult for other animals to eat it or catch it

accept ‘they stop it being eaten’

1 (L3)

(e) (i) any one from

• it keeps themwarmaccept ‘it insulates them’ OR it traps air

accept ‘it prevents them getting cold’

do not accept ‘it keeps the cold out’

1 (L3)

(ii) foxes or predators cannot see them

accept ‘they cannot be seen’ 1 (L3 )[6]

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