Adaptations

Plesiosaurs are extinct animals that lived in the ocean.

Figure 5 shows what scientists think a living plesiosaur may have looked like.

Scientists think that the plesiosaur had smooth skin.

Suggest why the scientists cannot be certain what the skin of the plesiosaur was like.

Explain how structure A in Figure 5 helped the plesiosaur survive in the ocean.

Plesiosaurs may have moved rapidly upwards to hold their heads above the water surface to search for prey.

What type of adaptation was the rapid upwards movement?

Tick () one box.

Scientists use fossils to estimate when different types of plesiosaur existed.

Figure 6 shows when three types of plesiosaur existed.

When did plesiosaur A first evolve?

Use Figure 6.

Determine how many million years plesiosaur B existed for.

Use Figure 6.

The exact year of extinction of all plesiosaur species can only be estimated.

Which are two reasons why?

Tick () two boxes.

What evidence from Figure 6 shows that plesiosaur C might have evolved from plesiosaur B ?

Tick () one box.

Evolution can be studied using evidence from:

• fossils

• antibiotic-resistant bacteria.

Suggest two reasons why it is easier to study evolution in bacteria than to study evolution using fossils.

Give one reason why doctors are concerned about antibiotic-resistant bacteria.

Plesiosaurs are extinct reptiles that lived in the ocean.

Figure 5 shows a fossil of a plesiosaur.

Plesiosaurs may have moved rapidly upwards to hold their heads above the water surface to search for prey.

What type of adaptation was the rapid upwards movement?

Give two biotic factors that may have caused the extinction of plesiosaurs.

Describe how the plesiosaur fossil in Figure 5 could have been formed.

Scientists use fossils to study evolution.

Suggest two reasons why scientists cannot study the mutations involved in the evolution of plesiosaurs.

Do not refer to extinction in your answer.

Table 1 shows part of the classification of a plesiosaur.

Complete Table 1.

Give the binomial name of the plesiosaur in Table 1.

Figure 2 shows one species of bird on a bird feeder.

The birds use their beaks to reach nuts inside the bird feeder.

Cats sometimes eat the birds.

Give the food chain for the birds, cats and nuts.

Which organism in the food chain you gave in Question 03.1 is the primary consumer?

Cats are one biotic factor that affects the size of the bird population.

Which two of the following are biotic factors?

Tick (✓) two boxes.

Figure 3 shows the mean beak length of this species of bird from 1982 to 2007.

What was the mean beak length in 2000?

What type of adaptation is beak length?

Tick (✓) one box.

Figure 3 shows evidence of evolution in this species of bird.

Scientists have concluded that beak length in this species of bird is increasing.

Complete the sentences about the evolution of this species of bird.

Choose answers from the box.

The difference in beak length in the bird population

is called.

A change in a gene affects the beak length.

Change in a gene is called.

The birds with the longest beaks get more food.

Getting more food improves a bird’s chances of

survival and.

This process of evolution takes place over more

than one.

Birds of this species:

• live for about 3 years

• produce up to 24 eggs every year.

Why is evolution easier to study in birds than in humans?

Tick (✓) one box.

Bacteria also provide evidence for evolution.

Which statement describes evidence for evolution?

Tick (✓) one box.

Animals have adaptations to survive in their environment.

These adaptations may be structural, behavioural or functional.

Draw one line from each animal adaptation to the type of adaptation it is.

Animal adaptation
Type of adaptation

Plants also have adaptations.

Orchid plants have adaptations which make them one of the most successful plant groups.

Orchids rely on insects for pollination.

Figure 2 shows an orchid.

Which two features help orchids survive?

Tick (✓) two boxes.

Many orchid species grow in tropical rainforest ecosystems.

What name describes the variety of all the different species found in an ecosystem?

Tick (✓) one box.

Some species of orchid may become extinct because of deforestation.

Give one reason why tropical rainforests are being cut down.

Give one factor that might cause a species of orchid to become extinct.

Do not refer to deforestation in your answer.

Scientists have analysed the entire genetic material of one species of orchid.

What chemical is the genetic material made from?

What is the name for the entire genetic material of an organism?

Animals have adaptations to survive in their environment. These adaptations may be structural, behavioural or functional.

Draw one line from each animal adaptation to the type of adaptation it is.

Animal adaptation Type of adaptation

Plants also have adaptations. There are more than 28 000 known species of orchid plants.

Many orchid plants:

• grow attached to other types of plants

• have brightly coloured flowers

• produce large quantities of pollen

• produce thousands of tiny, light seeds.

Describe how these adaptations help orchid plants to survive and compete.

A rare orchid has been found in the mountains in China. The orchid has pale yellow flowers. DNA analysis of the genome shows that it is an ancestral species. All other present day orchids evolved from this ancestral species millions of years ago.

One present day species has bright purple flowers. Describe how an orchid with bright purple flowers may have evolved from the ancestral species which has pale yellow flowers.

The DNA code determines the sequence of amino acids which are joined together to form a specific protein. Table 3 shows part of the amino acid sequence for the colour pigment protein in five orchid species. The rest of the amino acid sequence is the same for all the species.

ala = alanine gly = glycine isoleu = isoleucine leu = leucine tyr = tyrosine Suggest which orchid species is most closely related to the ancestral species. Give a reason for your answer.

Scientists have removed microorganisms from inside rocks in caves in Mexico. The microorganisms have been trapped there for between 10 000 and 50 000 years. The caves are dark, very hot, humid and acidic.

Why are these microorganisms called extremophiles? Tick two boxes.

The microorganisms have been inactive for thousands of years but the scientists have reactivated them. Figure 2 shows the results of enzyme analysis on four enzymes, A, B, C and D. Three of the enzymes were from microorganisms found in the soil near the caves. One of the enzymes was from a reactivated microorganism from the caves.

Which enzyme comes from the microorganism from the caves? Tick one box.

Give the reasons for your answer to question 03.2

Carl Woese developed the ‘three-domain system’ of classification. Describe the ‘three-domain system’ of classification.

Most of the microorganisms from the caves were classified as belonging to the Archaea domain of the ‘three-domain system’. Suggest why.