Abiotic and biotic factors

In 2018, all the plants were removed from the soil in a 1000 m² area.

A wall was built around this area to keep people out.

In 2019, three species of plants were recorded growing in this area.

Two of these species were indigenous.

State what is meant by the term ‘indigenous’.

Name one piece of equipment that could be used to sample the number of indigenous plants in this area.

The area was surveyed every year and the number of plants of each species (A to H) was estimated.

Figure 13 shows the results.

State the trend shown by the data in Figure 13 for plant species C from 2019 to 2023.

A scientist suggested that the decrease in the number of plants of species B in 2021 was caused by competition from one of the other species of plant.

Which species is most likely to have out-competed species B in 2021?

Explain one way that this species could have out‑competed species B.

Give one way that species H could have moved into the area.

*(c) Figure 14 shows some plants growing in a small area of a 1000 m² field.

Devise a plan to estimate the number of named plant species growing in this field.

In 2018, all the plants were removed from the soil in a 1000 m² area.

A wall was built around this area to keep people out.

In 2019, three species of plants were recorded growing in this area.

Two of these species were indigenous.

State what is meant by the term ’indigenous’.

Name one piece of equipment that could be used to sample the number of indigenous plants in this area.

The area was surveyed every year and the number of plants of each species (A to H) was estimated.

Figure 5 shows the results.

State the trend shown by the data in Figure 5 for plant species C from 2019 to 2023.

A scientist suggested that the decrease in the number of plants of species B in 2021 was caused by competition from one of the other species of plant.

Which species is most likely to have out-competed species B in 2021?

Explain one way that this species could have out‑competed species B.

Give one way that species H could have moved into the area.

Plants also need water to grow.

Explain how water is absorbed into the plant.

A scientist decided to study the variety of living organisms in a garden.

The scientist wanted to use a random sampling technique.

Devise a plan the scientist could use to randomly sample the number of plant species in the garden.

The scientist also measured abiotic factors in the garden.

The pH of the soil was measured using a pH meter.

Describe how three other abiotic factors could be measured in the garden.

Mistletoe is a parasite that grows on some trees.

Figure 4 shows a tree with mistletoe growing on it.

Describe the feeding relationship between the mistletoe and the tree.

Nitrate fertilisers are used in the garden.

Explain why nitrate fertilisers are used in gardens.

In 2000, a council planted indigenous trees as part of a reforestation programme.

Why were indigenous trees used instead of non-indigenous trees?

The animal biodiversity in this reforested area was measured from 2004 to 2017.

Biodiversity is measured on a scale from 0 to 1.

0 = low biodiversity

1 = maximum biodiversity

Figure 8 shows the results.

Draw a straight line of best fit on Figure 8 to show the main trend in this data.

Estimate the animal biodiversity of the reforested area in 2022.

The data to calculate animal biodiversity was collected using the following method.

• a 100 m² area was chosen

• three 1 m² quadrats were placed randomly on the ground

• animals inside the quadrat were counted

• the number of each species of animal was recorded

State two ways that the quality of the results from this method could be improved.

State why point A on Figure 8 was ignored when considering the trend in animal biodiversity.

The data shown in Figure 8 was collected during the summer.

Explain why animal biodiversity would be different if the data had been collected in the winter.

A scientist observes that trees at the edge of a forest shade part of a field.

Describe how a belt transect could be used to see how light intensity affects the biodiversity of plants growing in the field.

There are three levels of organisation in an ecosystem.

Which order shows the levels of organisation from lowest to highest?

Figure 3 shows food webs for two gardens.

Slug pellets are put on the soil around the lettuce plants in garden A and garden B.

Slug pellets kill slugs.

A scientist predicts that the number of caterpillars will decrease in garden A.

Give one reason why the number of caterpillars will decrease in garden A.

The scientist predicts that the number of caterpillars will increase in garden B.

Give one reason why the number of caterpillars will increase in garden B.

Figure 4 shows the population of slugs in garden A for five years.

Slug pellets were used during the first year.

slug

Describe the trend in the slug population from year 1 to year 5.

Flatworms from New Zealand that eat slugs are now living in the UK.

Which term describes a species from one country that is living in another country?

Figure 5 shows tiny white animals called mites on the skin of a slug.

The mites feed on blood.

Explain why these mites are classed as parasites.

Figure 1 shows an area of woodland with some small plants growing in the ground between the trees.

(Source: © Maksym Holovinov/Shutterstock)

Figure 1

Name a group of organisms that break down the dead leaves and release mineral ions into the soil.

The mineral ions are absorbed from the soil into the roots of plants.

Describe how these mineral ions are transported from the roots to the leaves of the plants.

A scientist recorded the mean light intensity and the mean number of small plants per m² for six 25 m² areas of the woodland.

Figure 2 shows the results.

Explain the effect of light intensity on the number of small plants per m².

State one variable the scientist should have controlled to make sure the light intensity measurements could be compared.

The scientist selects an area near the edge of the woodland where many stinging nettles are growing.

This area is partly shaded by the trees.

Describe how the scientist should use a belt transect to investigate how light intensity affects the growth of stinging nettles.