Ecosystems

Adélie penguins are one species of penguin.

Adélie penguins feed in the ocean.

The penguins are part of a food web.

Which of the following is the producer in the food web?

Tick (✓) one box.

Algae

Fish

Fungi

Prey

Adélie penguins nest on the ground in large groups.

Figure 5 shows an Adélie penguin on a nest made of stones.

Describe how biotic factors could affect the population of the penguins.

Adélie penguin nests cover all the ground in one large circular area.

The number of Adélie penguin nests in the area was estimated to be 60 000

The mean area of an Adélie penguin nest is 2.0 m².

Calculate the radius of the large circular area covered by all of the penguin nests.

Use the equation:

area of circle = 3.14 × (radius)²

A scientist investigated the abundance and the distribution of a plant species near the penguin nests.

Explain why different methods are needed to sample abundance of a plant species and distribution of a plant species.

Fruit flies are small insects.

Figure 6 shows a fruit fly.

Fruit flies:

are easy to keep in containers

have a short time between one generation and the next generation

are used to study evolution.

Why is it easier to study evolution in fruit flies rather than in humans?

Tick () two boxes.

Fruit flies do not produce many offspring.

Fruit flies show more different characteristics than humans.

Many generations of fruit flies can be produced in less time.

The environment that the fruit flies are in can be controlled.

The fruit flies can fly between different places.

A scientist studied the length of fruit fly wings.

The scientist used selective breeding to produce a population of fruit flies with longer wings.

The first stages in the selective breeding process were:

Place five female fruit flies with the longest wings in a container.

Add five male fruit flies with the longest wings to the container.

Let these fruit flies breed.

Place the five female offspring with the longest wings in a new container.

Add the five male offspring with the longest wings to the new container.

What is the next stage in the process of selective breeding?

After many generations, the offspring all had long wings.

The scientist stopped selectively breeding the fruit flies.

After a further 15 generations, the fruit flies all had short wings.

Which process may have caused the fruit flies to have short wings?

Tick () one box.

Classification

Mitosis

Natural selection

Some fruit flies damage crops.

How can farmers kill fruit flies that damage crops?

Tick () one box.

Add fertiliser to the soil.

Place compost around the plants.

Spray crops with pesticide.

One species of fruit fly has been genetically modified (GM) to only produce male offspring.

Scientists can release large numbers of the GM fruit flies where wild fruit flies are damaging crops.

The GM fruit flies will breed with wild fruit flies.

Releasing the GM fruit flies will decrease the population of wild fruit flies.

What is one advantage of releasing the GM fruit flies?

Tick () one box.

GM fruit flies look different to wild fruit flies.

Less of the crop is damaged by fruit flies.

Wild fruit flies reproduce at a faster rate.

What is one disadvantage of decreasing the population of wild fruit flies?

Tick () one box.

Birds that eat fruit flies will have more food.

Food chains and food webs will be disrupted.

Fruit flies will have different characteristics.

Figure 1 shows a food chain.

Which of the organisms in Figure 1 is the primary consumer?

Name the predator of the fish in Figure 1.

Draw one line from each term to the definition of the term.

Food chains and food webs can be used to predict the effect of a decreasing number of polar bears.

Why is a food web more useful than a food chain?

Tick (✓) one box.

Food webs show where energy is wasted.

Most animals eat more than one type of prey.

Producers are at the start of all food webs.

Krill eat algae.

Algae store a mass of 68 arbitrary units of carbon in 1 year.

8% of the carbon stored in algae becomes part of the carbon stored in krill.

Calculate the mass of carbon that becomes stored in krill.

Use the equation:

mass of carbon stored in krill = mass of carbon stored in algae ×

_ Mass of carbon stored in krill = _______________________ arbitrary units

The minerals in sea water are one abiotic factor that affects algae.

Which are two other abiotic factors that affect algae?

Tick (✓) two boxes.

Food availability

Light intensity

Pathogens

Prey

Temperature

Figure 7 shows part of a food web from one ecosystem.

Define the term ‘ecosystem’.

Describe the difference between a population and a community in one habitat.

Humans kill narwhals for meat and skin.

Killing more narwhals can cause the number of seals to increase or decrease.

Explain why killing more narwhals can have two different effects on the number of seals.

The algae in Figure 7 store a mass of 68 arbitrary units of carbon in 1 year.

8.4% of the carbon in each stage of the food web is passed to the next stage.

Calculate the mass of carbon stored in tertiary consumers in 1 year.

Mass of carbon = _____________________ arbitrary units

Mineral ions are at: a low concentration in sea water

a high concentration in algae.

Name the process algae use to absorb mineral ions from sea water.

Algae and plants are producers.

Explain how not having enough magnesium ions and nitrate ions can limit the mass of carbon stored in producers.

Figure 10 shows a rock pool on a sea shore.

Rock pools are flooded twice a day with fresh sea water.

What is the community of the rock pool?

Tick (✓) one box.

The living organisms and abiotic factors in the rock pool

The number of different species in the rock pool

The number of predators and prey in the rock pool

The populations of all the species that live in the rock pool

Starfish are animals that live in rock pools.

A scientist investigated the effect that starfish had on the number of species in rock pools.

This is the method used.

1. Count the number of species in rock pool A and in rock pool B.

2. Regularly remove all the starfish from rock pool B.

3. Count the number of species in rock pool A and in rock pool B each year for 10 years.

Figure 11 shows the results.

Figure 12 shows a food web in the rock pools.

Starfish usually prefer to feed on mussels.

Mussels reproduce and grow more quickly than limpets, chitons, and barnacles.

After 10 years the only species left in rock pool B was mussels.

Explain the results shown in Figure 11 for rock pool B.

Use Figure 11 and Figure 12.

Explain the results shown in Figure 11 for rock pool A.

Some species of starfish can reproduce by cloning (asexual reproduction) and also by sexual reproduction.

Figure 13 shows what happens when starfish P reproduces by each type of reproduction.

During cloning a small piece of the starfish develops into a new starfish.

Before cell division, chromosomes replicate and the number of organelles increases.

Describe the stages in the process of cell division that produces offspring X.

Explain one advantage to the starfish of reproducing by cloning rather than reproducing by sexual reproduction.

Figure 1 shows part of a food web.

What is the source of energy for the nettle plants?

Tick (✓) one box.

Caterpillars

Soil

Sun

Which term describes the caterpillars in the food web?

Tick (✓) one box.

Primary consumer

Secondary consumer

Tertiary consumer

What is the name of one producer in the food web?

Tick (✓) one box.

Blue tits

Greenflies

Sparrowhawks

Wheat plants

Mice eat wheat plants and are eaten by sparrowhawks.

Complete the food web in Figure 1 by adding mice to Figure 1.

A sparrowhawk competes with other sparrowhawks for food.

Give one other factor sparrowhawks will compete for.

Do not refer to food in your answer.

The nettle plants were removed.

Explain how removing the nettle plants will affect the number of caterpillars.

Use Figure 1 on page 2.

Figure 3 shows a food chain.

Draw one line from each description to the organism in the food chain.

Which word describes the total number of crabs in this habitat?

Tick (✓) one box.

Explain what will happen to the number of loggerhead turtles if there are fewer crabs.

Use information from Figure 3.

What type of factor is a new predator?

Tick (✓) one box.

Female loggerhead turtles lay their eggs on sandy beaches.

Scientists recorded data about turtles on one beach.

Figure 4 shows:

• the number of eggs each turtle laid

• the length of the turtle that laid the eggs.

Describe the trend in the data on Figure 4.

Female loggerhead turtles return to the same beach each year to lay their eggs.

Global warming is causing the sea level to rise.

Explain the effect that sea levels rising might have on the number of loggerhead turtles.

Greenhouse gases are one cause of global warming.

Methane is a greenhouse gas.

The concentration of methane in the atmosphere was:

• 720 arbitrary units in 1840

• 1872 arbitrary units in 2018.

How many times greater was the concentration of methane in the atmosphere in 2018 than in 1840?

Which two human activities cause an increase in greenhouse gases in the atmosphere?

Tick (✓) two boxes.

Figure 7 shows part of a food web.

There are four levels of feeding relationship shown in the food web in Figure 7.

Algae are at level 1 in the food web.

Why is it difficult to identify the level of the loggerhead turtle in the food web?

Explain the effects a decrease in the population of clams could have on the other organisms in Figure 7.

Female loggerhead turtles lay their eggs in nests on sandy beaches.

Table 3 shows how the temperature of the nest affects the sex of the loggerhead turtles.

Explain how the continued use of fossil fuels could affect the population of loggerhead turtles.

Use information from Table 3.