Classification

Ichthyosaurs are reptiles that lived in the sea millions of years ago.

Figure 13 shows the fossilised remains of an ichthyosaur.

Suggest how the fossil in Figure 13 was formed after the ichthyosaur died.

The length of the image of the ichthyosaur in Figure 13 is 120 mm.

The real length of the ichthyosaur was 17 times longer than the image in Figure 13.

Calculate the real length of the ichthyosaur.

Give your answer in metres.

Table 5 gives the classification of the ichthyosaur in Figure 13.

Complete Table 5.

Choose answers from the box.

Ichthyosaurs were predators.

Ichthyosaurs are now extinct.

Scientists think that extinction of the ichthyosaurs was caused by increased competition with other predators for food.

Suggest two other possible causes of extinction of the ichthyosaurs.

Ichthyosaurs are reptiles that lived in the sea millions of years ago.

Figure 1 shows the fossilised remains of an ichthyosaur.

Suggest how the fossil in Figure 1 was formed after the ichthyosaur died.

The length of the image of the ichthyosaur in Figure 1 is 120 mm.

The real length of the ichthyosaur was 17 times longer than the image in Figure 1.

Calculate the real length of the ichthyosaur.

Give your answer in metres.

Table 1 gives the classification of the ichthyosaur in Figure 1.

Complete Table 1.

Choose answers from the box.

Ichthyosaurs were predators.

Ichthyosaurs are now extinct.

Scientists think that extinction of the ichthyosaurs was caused by increased competition with other predators for food.

Suggest two other possible causes of extinction of the ichthyosaurs.

Carl Linnaeus invented a classification system that places organisms into groups.

What is the name of the largest classification group in Linnaeus’s system?

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Linnaeus gave each species a binomial name.

Which two classification groups form the binomial name?

Tick (✓) two boxes.

Scientists think that the animals in Figure 2 all evolved from an ancestor that lived about 6 million years ago.

Figure 2 shows how the animals may have evolved.

What was the most recent time that the domestic dog and the golden jackal shared a common ancestor?

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Which present-day animal in Figure 2 is the most distant relative of the domestic dog?

Scientists think the grey wolf and the domestic dog had a common ancestor.

The common ancestor:

• lived about 32 thousand years ago

• is now extinct.

Give two possible causes of extinction.

32 thousand years ago, humans hunted other animals for food.

Wolves also hunted other animals for food.

Suggest one reason why wolves began to follow groups of humans.

Some wolves are more aggressive than other wolves.

Describe how selective breeding of wolves could produce a domestic animal that is less aggressive than the wolf.

Many different species can live together in the same habitat.

What name is given to all of the organisms living in the same habitat?

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Figure 12 shows four species of bird from the same habitat in the UK.

Brambling (Fringilla montifringilla)
Bullfinch (Pyrrhula pyrrhula)

Chaffinch (Fringilla coelebs)
Goldfinch (Carduelis carduelis)

Which species of bird in Figure 12 do scientists think are most closely related?

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Scientists think the brambling and the bullfinch belong to different species.

What evidence is used by scientists to classify the brambling and the bullfinch as different species?

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Four other species of bird (A, B, C and D) live in a habitat in the UK.

Figure 13 shows how the numbers of each species of bird varied during one year.

Use information from Figure 13 to answer Questions 07.4 to 07.6

Describe what happens to the number of birds of species A during the year.

In June and July, a disease affected the populations of some of the species.

Which species had the lowest resistance to the disease?

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One species migrates between the UK and other countries.

Which species migrates between the UK and other countries?

Give a reason for your answer.

Many different species can live together in the same habitat.

What name is given to all of the organisms living in the same habitat? Tick (✓) one box.

Figure 1 shows four species of bird from the same habitat in the UK.

Brambling (Fringilla montifringilla) Bullfinch (Pyrrhula pyrrhula)

Chaffinch (Fringilla coelebs) Goldfinch (Carduelis carduelis)

Which species of bird in Figure 1 do scientists think are most closely related? Tick (✓) one box.

Scientists think the brambling and the bullfinch belong to different species. What evidence is used by scientists to classify the brambling and the bullfinch as different species? Tick (✓) one box.

Four other species of bird (A, B, C and D) live in a habitat in the UK. Figure 2 shows how the numbers of each species of bird varied during one year.

Use information from Figure 2 to answer Questions 01.4 to 01.6

Describe what happens to the number of birds of species A during the year.

In June and July, a disease affected the populations of some of the species. Which species had the lowest resistance to the disease? Tick (✓) one box.

One species migrates between the UK and other countries. Which species migrates between the UK and other countries? Give a reason for your answer.

Living organisms can be classified into groups. Trilobites are animals that lived in the sea 400 to 500 million years ago. Table 3 gives the classification of two species of trilobite.

Complete Table 3. Choose answers from the box.

Which scientist invented the classification system given in Table 3 ? Tick (✓) one box.

What is the binomial name of trilobite A ? Use information from Table 3. Tick (✓) one box.

Figure 10 shows fossils of the two species of trilobite.

Figure 11 shows:

• layers of rock in a cliff

• where the trilobite fossils were found.

A scientist made the hypothesis: ‘Trilobite B may have evolved from trilobite A.’

What two pieces of evidence from Figure 10 and Figure 11 support the scientist’s hypothesis? Tick (✓) two boxes.

Trilobites are animals that lived in the sea. Complete the sentences about how the fossils of trilobites A and B were formed. Choose answers from the box.

The animal dies and falls to the sea bed.

The of the animal decay.

Trilobites A and B are now extinct. Give three possible causes of extinction.

Suggest one reason why scientists cannot be sure what caused the trilobites to become extinct.

Potato blight is a disease of potato plants. Potato blight is caused by the fungus Phytophthora infestans.

What is the genus of the fungus that causes potato blight?

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The fungus grows near the surface of the potato. How does growing near the surface help the fungus to respire?

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A farmer sprays his potato plants with a pesticide.

The pesticide kills the fungus that causes potato blight. Spraying the crop with a pesticide could decrease biodiversity in a river flowing through his farm.

What does ‘biodiversity in a river’ mean?

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The farmer sprayed pesticide on his potato plants. The next day it rained heavily. Explain why the biodiversity in the river decreased.

Another method of preventing potato blight is to breed potatoes that are resistant to blight. Resistance to potato blight is controlled by two alleles: R = a dominant allele for having resistance to blight. r = a recessive allele for not having resistance to blight. A scientist crosses two potato plants. Each plant has the genotype Rr.

Complete Figure 9 to show the possible genotypes of the offspring produced.

Draw a ring around one of the homozygous genotypes in Figure 9.

What percentage of the offspring in Figure 9 will be resistant to potato blight?

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Potatoes can also reproduce asexually. Potatoes from one plant can be planted in the ground to produce new potato plants. All the new plants from a parent plant that is resistant to blight will also be resistant to blight. Explain why.

The Galapagos Islands are located in the Pacific Ocean. Several species of birds called finches live on the Galapagos Islands. These finches are very similar to each other. Figure 15 shows two modern species of Galapagos finch and their classification.

Figure 15

Medium ground finch Small ground finch

Complete Figure 15 to give the names of the missing classification groups.

Give the binomial name of the medium ground finch. Use information from Figure 15.

In each species of finch, there is a variation in beak depth.

Figure 16 shows how beak depth is measured.

Figure 17 shows the relationship between the beak depth of parent birds and the beak depth of their offspring.

Give evidence from Figure 17 that beak depth is an inherited characteristic.

Scientists suggested that more than one gene controls beak depth. Give evidence from Figure 17 to support the scientists’ suggestion.

Figure 18 is a map of the Galapagos Islands.

On Isabela Island, the medium ground finch and the small ground finch are found. On Daphne Island, only the medium ground finch is found. On Crossman Island, only the small ground finch is found. Figure 19 shows how the beak depth of each species varies on each island.

The medium ground finch and the small ground finch both feed on seeds.

The size of seeds eaten by each bird depends on the depth of the bird’s beak.

The range of beak depth of medium ground finches on Isabela Island is different from the range on Daphne Island. Explain what might have caused this difference.

Figure 19 shows:

• the two species of finch live on Isabela Island

• only one of the species lives on Daphne Island

• only one of the species lives on Crossman Island.

Suggest why both species of finch are able to live on Isabela Island.

Figure 8 shows what the extinct Siberian rhinoceros (Elasmotherium sibiricum) might have looked like.

What is the genus of the Siberian rhinoceros?

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The ‘three-domain system’ of classification places all living organisms in one of three domains.

Which domain was the Siberian rhinoceros in?

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Who developed the ‘three-domain system’ of classification?

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The horn of the Siberian rhinoceros is estimated to have been 150 cm long.

Suggest one advantage of this adaptation to the Siberian rhinoceros.

The only parts of the Siberian rhinoceros that have been found are fossilised bones.

Give one reason why only the bones of the body of the Siberian rhinoceros became fossils.

Suggest how scientists can estimate when the Siberian rhinoceros was alive.

Figure 9 shows when the Siberian rhinoceros existed and when modern humans existed.

How many million years ago did the Siberian rhinoceros become extinct?

Determine the time in years when both the Siberian rhinoceros and modern humans existed together.

Use Figure 9 and your answer to Question 06.7.

Suggest two factors that may have caused the extinction of the Siberian rhinoceros.

Figure 10 shows a flightless bird called the dodo (Raphus cucullatus).

The dodo:

• was 1 m tall

• had a mass of 20 kg

• lived in rainforests on a tropical island

• ate fruits

• made its nest on the ground.

A female dodo laid only one egg each year.

Humans arrived on the island in the year 1507. By 1681 the dodo was extinct.

What is the genus of the dodo?

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Before the arrival of humans, there were no other large animals living on the island.

Suggest two reasons why the dodo became extinct soon after the arrival of humans.

Today, humans are cutting down large areas of tropical rainforests.

Suggest one use of the land after the trees have been removed.

Why does the removal of trees cause an increase in carbon dioxide in the atmosphere?

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What effect would an increase in carbon dioxide in the atmosphere have on global air temperature?

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‘Sustainable forestry’ reduces the harmful effects of cutting down trees on the environment.

Figure 11 shows a method of ‘sustainable forestry’.

Numbers 1–9 show different parts of a rainforest.

The trees are cut down in the sequence 1 – 2 – 3 – 4 – 5 – 6 – 7 – 8 – 9

• The trees are cut down in only one area at any one time.

• It takes 30 years to cut down the trees in each area.

• The trees in the ‘Old growth’ area are never cut down.

How many years would it take to cut down the trees in all of the numbered areas in Figure 11 ?

The rainforest contains:

• 750 species of trees

• 400 species of birds

• 150 species of butterflies

• many other species of plants and animals.

Explain how the pattern of cutting down trees shown in Figure 11 stops the biodiversity of the rainforest being reduced.

Table 2 gives the classification of four plant species.

Species 1 and 3 are the most closely related.

What information in Table 2 gives evidence for this?

Figure 6 shows the inheritance of flower colour in two species of plant.

• In pea plants and in snapdragon plants, flower colour is controlled by one pair of alleles.

• In Figure 6 the parental generation plants are homozygous for flower colour.

• In heterozygous pea plants, the allele for red flower colour is dominant.

• In heterozygous snapdragon plants, the alleles for flower colour are both expressed.

Use the following symbols for alleles in your answers to Questions 05.2 to 05.4:

Pea plants
Snapdragon plants

R = allele for red flowers C^R = allele for red flowers r = allele for white flowers
C^W = allele for white flowers

What is the genotype of the red-flowered pea plants in the F₁ generation?

What is the genotype of a white-flowered snapdragon plant?

A gardener crossed two pink-flowered snapdragon plants.

Draw a Punnett square diagram to show why only some of the next generation plants had pink flowers.

Identify the phenotypes of all the offspring plants.

What percentage of the offspring would you expect to have pink flowers?

Commercially, hundreds of pink-flowered snapdragon plants can be produced from one pink-flowered plant.

Figure 7 shows a tissue culture technique used for producing many plants from one plant.

Give a reason for each of the following steps shown in Figure 7.

Several groups of cells are scraped off the leaf:

Nutrients are added to the agar jelly:

Hormones are added to the agar jelly:

The plant cells are kept in sterile conditions:

The plant cells are kept at 20^oC:

Explain why the method shown in Figure 7 produces only pink-flowered plants.

Figure 12 shows a ring-tailed lemur.

Table 5 shows part of the classification of the ring-tailed lemur.

Complete Table 5 to give the names of the missing classification groups.

Give the binomial name of the ring-tailed lemur.

Use information from Table 5.

Lemurs are only found on the island of Madagascar.

Madagascar is off the coast of Africa.

Scientists think that ancestors of modern lemurs evolved in Africa and reached Madagascar about 50-60 million years ago.

Today there are many species of lemur living on Madagascar.

Figure 13 shows information about water currents.

Figure 14 shows the distribution of three species of lemur on Madagascar.

Suggest how ancestors of modern lemurs reached Madagascar.

Describe how the ancestors of modern lemurs may have evolved into the species shown in Figure 14.