AQA GCSE Biology: Combined Science

Topic Questions

7.1 Adaptations, Interdependence & Competition

1a2 marks

The following terms are all names that represent groups of organisms.

  • Community
  • Population
  • Ecosystem
  • Biosphere

The largest group of these is Biosphere.

Place the remaining three groups in the table below in descending size order.

levels-of-organisation

1b1 mark

Which word from A - D best completes the sentence below?

A population includes all the members of one ___________ in the same place at the same time. 

  • community

  • type

  • species

  • gender

1c1 mark

Figure 1 shows part of a food web from a pond ecosystem. 

Figure 1
pond-food-web-1

Identify the organism in Figure 1 that the snake competes intraspecifically with.

1d1 mark

Apart from food, in a pond ecosystem like that shown in Figure 1, state one resource that the small fish and the trout may compete against each other for. 

1e2 marks

In the pond ecosystem shown in Figure 1, the heron is referred to as a predator. 

Define the term 'predator'.

Did this page help you?

2a1 mark

The organisms in an established ecosystem are said to be interdependent.

Define the term 'interdependence'.

2b1 mark

Explain the importance of interdependence in an ecosystem.

2c1 mark

In a forest ecosystem, plants compete for resources.

Which of A - D is not a resource that plants would compete for in a forest ecosystem?

  • Food

  • Light

  • Space

  • Mineral ions

2d
Sme Calculator
2 marks

In a small piece of woodland in the UK, the number of each group of organisms present was counted over a 20-year period. From 2001 onwards, the woodland was thinned out by a timber company for the valuable wood that grew there.

Table 1 shows the change in the organisms present over the 20-year period.

Table 1

Year Number of mature trees Grass cover in hectares Number of insect species Number of bird species
2000 56 2.1 400+ 61
2010 31 2.4 250 27
2020 14 3.9 188 19

Calculate the percentage increase in grass cover over the 20 year period, from 2000 to 2020.

2e3 marks

Using the data in Table 1, describe two trends that have been observed in the piece of woodland over the period 2000 to 2020 as a consequence of the reduction in the number of trees.

For one of these trends, suggest an explanation for what has been observed. 

Did this page help you?

3a2 marks

Table 2 below lists a number of biotic and abiotic factors affecting the spread of organisms. 

Table 2

Factor Biotic Abiotic
Soil pH    
Parasites    
New predators    
Moisture level    
Wind speed    
Competition    

Place a tick (✔) in the correct box in each row of Table 2 to identify each factor as biotic or abiotic.

3b2 marks

Figure 2 shows part of a food web from Yellowstone National Park in the USA.

Figure 2

yellowstone-food-web-1

Wolves were eradicated from the park in the years 1920-1995.

Suggest the impact of the wolves' eradication on the elk and willow.

3c1 mark

State the role of the coyote in the food web shown in Figure 2.

3d2 marks

Wolves were reintroduced to the park in the early 2000s. In the years that followed the aspen population increased.

With reference to the food web in Figure 2, suggest why the population of aspen trees increased when wolves were reintroduced to the park.

Did this page help you?

4a3 marks

Figure 3 shows a number of adaptations of organisms and the types of adaptation that can exist.

Figure 3

adaptations-q-1

Join each box on the left to the appropriate box on the right of Figure 3 with straight lines.

4b2 marks

Figure 4 shows an African leopard. Leopards have a distinctive pattern of spots on their coats.

Figure 4

african-leopard-1Explain how the leopard's spots help it to survive in its habitat. 

4c1 mark

The African leopard shown in Figure 4 can be regarded as a competitor to other large carnivorous wild cats in the same habitat, such as the lion and the cheetah.

Suggest one kind of resource (apart from food/prey) that the leopard would compete for against the lion and the cheetah.

4d1 mark

Certain species of microorganisms are adapted to live in environments in which most other living organisms would not survive.

State the collective name of these microorganisms.

Did this page help you?

5a1 mark

Identify which of A - D is an adaptation that enables a plant to live in a hot, dry environment.

  • A large number of leaves

  • Deep green leaves - a lot of chlorophyll

  • A widespread root network

  • High numbers of stomata

5b2 marks

Two plant species are shown in Figure 5. The cactus is adapted to live in dry conditions, whereas the rubber plant tree is adapted to live in areas of high rainfall. 

Figure 5

rubber-plant-and-cactus-1

From the visible features in Figure 5, identify and explain one adaptation of the cactus that makes it well adapted to living in hot, dry conditions. 

5c2 marks

Polar bears and seals, like the ones shown in Figure 6, are both adapted for survival in very cold conditions. 

Figure 6

polar-bear-and-seal-1

Identify two structural adaptations that enable both animals to live in cold conditions. 

1.____________________________________________________________

2.____________________________________________________________

5d1 mark

Some animals are crepuscular, which means that they are only active at dawn or dusk. For the remaining time, they sleep or rest to conserve energy.

Which term from A - D best describes this kind of adaptation?

  • Behavioural

  • Functional

  • Sequential

  • Structural

Did this page help you?

1a
Sme Calculator
2 marks

Extremophiles are (most commonly) microorganisms; these are adapted to live in extreme chemical or geophysical conditions. 

In some cases, scientists attempting to discover the genetic composition of extremophiles have struggled to break open their cells in an attempt to isolate their DNA.

Suggest why it has been difficult to access the DNA of certain extremophiles for research purposes.

1b
Sme Calculator
2 marks

Figure 1 is a sketch graph showing the effect of increasing temperature on the activity of a typical human enzyme.

Figure 1

thermophile-enzyme-sketch-1

The thermophilic microorganism Methanopyrus kandleri thrives at temperatures around 120°C

Sketch a line on the graph in Figure 1 to show the effect of increasing temperature on the activity of an enzyme from Methanopyrus kandleri.

1c
Sme Calculator
1 mark

Certain thermophilic bacteria are known as obligate thermophiles.

Select A - D which best defines the term 'obligate thermophiles'.

  • Bacteria which can survive in cold and hot temperatures.

  • Bacteria which can only survive in hot temperatures.

  • Bacteria which can only survive in cold temperatures.

  • Bacteria which are destroyed at moderate temperatures.

1d
Sme Calculator
2 marks

Thermophilic organisms have been used in the following processes

    • The manufacturing of biological washing powder
    • The degradation of pollutants
    • Bioremediation of oil-contaminated soil in the desert
    • Removal of heavy metals in the soil
    • The conversion of biomass to biofuels
    • The degradation of toxic textile dyes

Explain why thermophilic bacteria are chosen for these roles over bacteria that are adapted for life at more moderate temperatures. 

Did this page help you?

2a
Sme Calculator
2 marks

Figure 2 shows two species of squirrel, the red squirrel (Sciurus vulgaris) and the grey squirrel (Sciurus carolinensis).

Figure 2

red-and-grey-squirrel-1

Grey squirrels were introduced to the UK mainland as an ornamental species in the 19th century but have since replaced the native red squirrel as the dominant species in the UK. Red squirrels have now receded from Wales and much of England, but they remain present in the far north of England and Scotland. 

What evidence from Figure 2 shows that this is an example of interspecific competition?

2b
Sme Calculator
2 marks

Because of differences in the two species' digestive systems, grey squirrels are able to feed on 'green' (immature) acorns, whereas red squirrels require the acorns to be ripe (mature). 

Suggest how this affects competition between the two species of squirrel. 

2c
Sme Calculator
4 marks

Another factor that favours the grey squirrel is that the red squirrel is susceptible to the squirrelpox (Parapox) virus, which is carried by greys but does not affect them. 

The red squirrel's plight can be helped by a number of human interventions designed to prevent its extinction. Two of these are:

  • Understanding the red and grey squirrels' genes by analysing all of its DNA
  • Creating a captive breeding programme for red squirrels in partnership with zoos and wildlife organisations

Explain how each of these two measures can contribute to saving the red squirrel from extinction. 

2d
Sme Calculator
1 mark

All squirrels have a varied diet which consists of tree seeds, acorns, nuts and berries. Squirrels can be prey to owls, pine martens and stoats.

Apart from any effect on the red squirrel population, predict one effect that a decrease in the grey squirrel population will have on a woodland ecosystem. 

Did this page help you?

3a
Sme Calculator
2 marks

Researchers looking into the effects of climate change investigated the effect of changes in the amount of rainfall on the number of plant species found growing naturally in a piece of woodland.

Over a 20-year period, the overall rainfall was recorded annually, along with the number of different plant species found and identified in the test area.

The results are shown in a scatter graph in Figure 3. Each data point represents a separate year. A line of best fit has been plotted with the data. 

Figure 3

precipitation-on-richness-q-1

Apart from this scientific work, no human activity took place in the piece of woodland during the study. State two other precautions that the researchers would have taken to make sure this was a valid investigation. 

3b
Sme Calculator
4 marks

The tourist office in the area of the study in question 3a) saw the researchers' data and used it to promote the area as a venue for eco-tourism. A section of their tourist brochure is shown in Figure 4 below.

Figure 4

rainfall-2

Evaluate the claim (circled in Figure 4) made by the tourist office. 

3c
Sme Calculator
1 mark

Referring to the data shown in Figure 3, choose the statement from A - D that could be a valid conclusion from the data in the investigation. 

  • There was a trend of rainfall getting heavier over time. 

  • The plants grew larger with more rainfall. 

  • Higher than average rainfall tended to allow more plant species to grow in the area. 

  • Double the average rainfall attracted double the number of different plant species. 

3d
Sme Calculator
2 marks

For the data in Figure 4, deduce the median number of plant species found throughout the course of the investigation. Figure 4 is reproduced below for convenience. 

Show your working. 

Figure 4 (repeated)

precipitation-on-richness-q-1

Did this page help you?

4a
Sme Calculator
5 marks

Figure 5 shows a coypu (Myocastor coypus), a large rodent native to South American countries. Coypus are large, semi-aquatic rodents that feed on vegetation and tree bark. 

Figure 5

coypu-1

Coypus were introduced into North America in the 20th century, in order for them to be farmed for their fur. Some escaped into the wild and they have become a major nuisance species. Coypus feed on tall grasses and rushes, which are a source of food, nesting sites, and shelter for many organisms. These plants also help to stabilise sediment and soil. Coypus have caused widespread damage to the area’s food web and habitats by consuming the wetland grasses.

Explain how the introduction of coypus might have caused their population, and those of wetland grasses and the animals that live within them, to fluctuate over subsequent years. 

4b
Sme Calculator
2 marks

Apart from the availability of food, give two other biotic factors that could influence the size of the coypu population. 

4c
Sme Calculator
4 marks

Describe and explain the following phrase:

In a predator-prey relationship, their populations are always out of phase. 

Did this page help you?

5a
Sme Calculator
2 marks

Figure 6 shows five instruments used commonly to measure and record abiotic factors in ecological investigations. The boxes to the right show five abiotic factors measured using these instruments.

Figure 6

abiotic-join-boxes-q-1

Using five straight lines, link each instrument to the abiotic factor that it is used to measure and record.  

5b
Sme Calculator
2 marks

An important abiotic factor for aquatic ecosystems is the dissolved oxygen level (in water). A good level of dissolved oxygen allows fish and other aquatic animals to breathe successfully underwater. Figure 7 shows a dissolved oxygen meter. Its probe can be immersed to measure the level of dissolved oxygen in a body of water. 

Figure 7

do2-meter-1

State two conditions that will ensure that a good level of dissolved oxygen can exist in a stream. 

5c
Sme Calculator
1 mark

An oxygen meter like the one shown in 5b) was used to record oxygen levels in a river. Two points were sampled , A and B, upstream and downstream from a sewage treatment plant. The layout is shown in Figure 8.

Figure 8

sewage-1

The dissolved oxygen levels were measured and recorded in Table 1.

Table 1

Location Dissolved oxygen level in mg per litre Flow rate in cubic metres per minute
A 11.2 33
B 4.4 19

Suggest a reason for the drop in dissolved oxygen between sampling points A and B

5d
Sme Calculator
2 marks

Explain why turbulent river water is better for aquatic wildlife in some respects, yet worse in others. 

Did this page help you?

6a
Sme Calculator
4 marks

Compare and contrast intraspecific and interspecific competition, in a biological setting. You may choose to refer to named examples of organisms in your answer.

6b
Sme Calculator
4 marks

For lions in countries like Kenya, two male lions would fight for the right to mate with the females in that pride. The loser is driven away from the pride by the winner, and so does not get the chance to mate; he must try to find a mate in another pride. 

Explain why males fight for a mate and the genetic consequences of such conflicts. 

Did this page help you?

1a1 mark

Limpets are a type of aquatic snail found along coastlines in the UK.

They can attach themselves to rocky surfaces using their muscular foot, as shown in Figure 1.

Figure 1

figure

Suggest why it is essential that limpets can attach themselves to surfaces like a rock by exerting a large force. 

1b2 marks

A group of scientists investigated the distribution of different species of limpet over various parts of a rocky shore. 

The high tide water mark is the highest level that seawater reaches along a shoreline. 

Each bar in Table 1 represents where limpets were found along the shore. 

Table 1

limpets

Identify which two species of limpet would be most likely to be in competition with each other. Give a reason for your choice. 

1c2 marks

L. digitalis cannot survive higher up the shore, whereas L. paradigitalis can.

Suggest two reasons why L. digitalis cannot survive higher up the shore.

1d4 marks

Like fish, limpets exchange oxygen and carbon dioxide from water drawn through their gills. 

Although some species of limpet take in oxygen directly from the air, all limpets should avoid drying out.

Limpet species found near the high-tide water mark tend to have a more domed shell, whereas those found nearer the low-tide water mark tend to have wider, flatter shells. 

Suggest, with reasons, two possible explanations for this. 

1e4 marks

Figure 2 shows an example of a food web which includes limpets.

Figure 2

food-web

Use organisms from the food web in Figure 2 to explain what is meant by the term, 'interdependence'.

Did this page help you?

2a3 marks

A student wanted to investigate how different abiotic factors affect the growth and distribution of daisies in the field behind his school.

The distribution of daisies in the field could be affected by environmental factors such as sunlight. 

Give three other abiotic factors that might affect the distribution of daisies in a field. 

2b3 marks

Explain how the amount of sunlight could affect the distribution of daisies in the field.

Did this page help you?

3a4 marks

Desert animals are adapted to survive in very hot, dry conditions. 

Many are nocturnal (only active at night) or crepuscular (only active at dawn and dusk).

Some animals do not sweat, or sweat only after a significant increase in body temperature. 

Others have adapted in more extreme ways, with organs such as the heart and liver shrinking at the height of the dry season, reducing the energy demand of these organisms. 

Suggest how some of the adaptations described above help desert animals survive in hot, dry conditions. 

3b4 marks

Figure 3 below shows an arctic fox (left) and a desert fox (right).

Figure 3

q3b_adaptations-interdependence-competition_ecology_gcse_aqa_biology

Animals living in cold climates tend to have different body shapes to those living in hotter climates.

Identify a difference in body shape between these two types of fox and explain the difference based on the habitat that each fox occupies.  

3c3 marks

It has been observed that there are far fewer living species at higher latitudes, closer to the poles, than there are living species a lower latitudes, closer to the equator. 

The time taken for evolution to occur at higher latitudes is also considered to be much shorter than at lower latitudes.

Suggest explanations for these two observations. 

Did this page help you?

4a
Sme Calculator
1 mark

The Norris Geyser Basin in Yellowstone National Park is a pool of boiling, acidic water. 

A number of species of bacteria have been found living in the geyser, including Thermus aquaticus.

What term is used to describe organisms that can survive in severe conditions such as the boiling, acidic water of the Norris Geyser Basin?

4b
Sme Calculator
2 marks

Taq polymerase is a thermostable enzyme found in Thermus aquaticus in the Norris Geyser Basin.

Suggest an explanation why most microorganisms cannot survive at high temperatures such as those found in the Norris Geyser Basin, but Thermus aquaticus can survive. 

4c4 marks

In the 18th Century, an English settler in Australia released a number of rabbits into the wild for hunting purposes. 

Rabbits are not native to Australia. 

There are now millions of rabbits in Australia, and they are thought to be responsible for the loss of a number of native species. 

In the 1990s, a number of lionfish escaped into the Atlantic Ocean from an aquarium; their population in the Atlantic now numbers in the thousands. 

Suggest explanations for the large increases in population size of both species described above. 

Did this page help you?

5a2 marks

Define the following two terms:

(i) Adaptation

[1 Mark]

(ii) Ecosystem

[1 Mark]

5b3 marks

Desert plants have many adaptations for surviving in desert areas.

Some plants have a dual-root system, with a small number of deep, bulbous roots and a large number of shallow roots spread out over a wide area.

Suggest how the dual-root system allows desert plants to survive.

5c3 marks

Suggest and explain three possible adaptations that the leaves of desert plants may have. 

Did this page help you?