Natural selection

This question is about genetics.

Figure 9 shows two lions.

One lion has brown fur.

One lion has white fur.

White fur colour in lions is caused by a mutation.

How could a mutation cause white fur colour?

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The mutation could cause cells to divide.

The mutation could prevent the growth of cells.

The mutation could stop cells producing a protein.

Lions live in areas of grass.

The dry grass is often brown.

White lions are very rare in the wild.

Explain why natural selection is likely to result in low numbers of white lions in the wild.

The allele for brown fur is dominant.

The allele for white fur is recessive.

A heterozygous male lion and a homozygous recessive female lion produce one offspring.

Determine the probability that the offspring will have white fur.

You should:

complete Figure 10

use the symbols: B = allele for brown fur b = allele for white fur

identify the colour of fur for each offspring genotype

give the probability of the offspring having white fur.

This question is about genetics.

Figure 2 shows two lions.

One lion has brown fur.

One lion has white fur.

White fur colour in lions is caused by a mutation.

How could a mutation cause white fur colour?

Tick (✓) one box.

The mutation could cause cells to divide.

The mutation could prevent the growth of cells.

The mutation could stop cells producing a protein.

Lions live in areas of grass.

The dry grass is often brown.

White lions are very rare in the wild.

Explain why natural selection is likely to result in low numbers of white lions in the wild.

The allele for brown fur is dominant.

The allele for white fur is recessive.

A heterozygous male lion and a homozygous recessive female lion produce one offspring.

Determine the probability that the offspring will have white fur.

You should:

complete Figure 3

use the symbols: B = allele for brown fur b = allele for white fur

identify the colour of fur for each offspring genotype

give the probability of the offspring having white fur.

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?

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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?

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Classification

Mitosis

Natural selection

Some fruit flies damage crops.

How can farmers kill fruit flies that damage crops?

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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?

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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?

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Birds that eat fruit flies will have more food.

Food chains and food webs will be disrupted.

Fruit flies will have different characteristics.

Figure 7 shows an oak tree.

The binomial name of the oak tree is Quercus robur.

What is the genus name of the oak tree?

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Oak

Quercus

Robur

Other species of tree are in the same genus as Quercus robur.

What does it mean if two species of tree are in the same genus?

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The two species are always found in the same place.

The two species are closely related to each other.

The two species look exactly the same.

Oak trees grow at points where cells can divide.

Growth in oak trees happens at the tips of the branches.

Name the type of tissue at the tips of the branches.

Oak trees reproduce by sexual reproduction to produce seeds.

An acorn is a nut that contains a seed.

The seed may become a new oak tree.

Which process produces the cell that grows into the seed?

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Evolution

Fertilisation

Translocation

One type of insect lays eggs in acorns.

The insect eggs cause the acorn to grow abnormally.

The abnormal growth is called a gall.

Insect embryos grow inside the gall.

Figure 8 shows a normal acorn and an acorn that has grown a gall.

The gall is made from oak tree cells that have divided.

The cells of the gall contain two sets of chromosomes.

Which process produces the cells of the gall?

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Circulation

Digestion

Mitosis

The insects have changed over time and caused a gall to grow on acorns.

The gall increases the chance of survival of the insects inside the gall.

What name is given to the process of the insects changing over time?

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Clone production

Evolution

Inbreeding

The oak tree transports water and nutrients to the insect embryos inside the gall.

Enlarge

Water moves from the roots to the leaves.

Name the process that moves water from the roots to the leaves.

This question is about plant tissues.

Plant meristem tissue is found in the growing tips of shoots and roots.

Name two processes in plants that only occur in meristem tissue.

An acorn is a nut that contains the seed of an oak tree.

When one type of insect lays an egg in an acorn, the acorn grows abnormally.

The abnormal growth is called a gall.

An insect embryo grows inside the gall.

Figure 8 shows a normal acorn and an acorn that has grown a gall.

The seed in an acorn forms from one original cell with two sets of oak tree chromosomes.

The original cell in each seed was produced by sexual reproduction.

The gall has cells that contain two sets of oak tree chromosomes.

Compare the process that produced the original cell in each seed with the process that produced cells in the gall.

The insect embryo inside the acorn:

causes the growth of the gall

uses nutrients from the gall to grow

causes lignin to form around the outside of the gall.

The lignin around the gall protects the acorn from being eaten by herbivores.

Which other structure in the oak tree contains lignin?

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Phloem

Root hair cells

Xylem

Many years ago, a mutation of an insect embryo led to the embryo causing lignin production in an acorn.

Explain how the mutation could have produced a population of insects that all cause lignin production.

Figure 5 shows a light microscope.

A student was given a prepared slide of cells.

Describe how the microscope in Figure 5 could be used to view the cells with the high power objective lens.

Light microscopes are not used to view viruses.

What are two reasons why electron microscopes are used to view viruses?

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Electron microscopes are expensive to maintain

Electron microscopes can have a magnification of ×1 000 000

Electron microscopes have a high resolving power

Viruses are not living organisms

Viruses are found and are replicated inside living cells

Plant species Q is not resistant to one type of virus.

Explain how the process of natural selection could result in all plants of species Q having resistance to the virus.

Classification of living organisms has changed over time.

Cabbage and cauliflower plants are both the same species, Brassica oleracea.

What is the genus name of cabbage and cauliflower?

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Brassica

Brassica oleracea

Oleracea

Figure 5 shows the evolution of some plants.

Cabbage and cauliflower evolved into a new species 9 million years ago.

Rapeseed and turnip evolved more recently.

How many million years ago did rapeseed and turnip evolve into two species?

_________________ million years ago

Farmers have gradually changed Brassica oleracea over thousands of years to produce different varieties.

Which process produced the different varieties of Brassica oleracea ?

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Active transport

Selective breeding

Transpiration

Scientists investigated the genome of cabbage and the genome of cauliflower.

What does genome mean?

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A mutation in the DNA

All of the DNA in an organism

The DNA in one gene

Cabbage and cauliflower have some of the same genes.

Figure 6 shows the number of genes found:

only in cabbage

only in cauliflower

in cabbage and in cauliflower.

Cabbage contains a total of 30 000 genes.

Calculate the percentage of genes in cabbage that are found in both cabbage and cauliflower.

Use the equation:

How does Figure 6 provide evidence that cabbage and cauliflower are closely related?

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Cabbage and cauliflower contain the same number of genes.

More genes are only found in cauliflower than only in cabbage.

Most genes are the same in cabbage and in cauliflower.

Figure 4 shows the evolution of some plants.

A, B, C, D and E show when one species evolved into two species.

Use Figure 4 to answer Questions 04.1 to 04.3.

Give the genus name of salt cress.

Cabbage, cauliflower and kale are all varieties of one species, Brassica oleracea.

How many years ago did rapeseed evolve to become a different species from cabbage, cauliflower and kale?

________________________ million years ago

Give the binomial names of two species that evolved 5 million years ago.

It has taken thousands of years for farmers to produce the different varieties of Brassica oleracea.

Describe how farmers have been able to produce the different varieties of Brassica oleracea.

Describe how scientists can prove that cabbage and cauliflower plants are the same species.

Do not refer to DNA analysis in your answer.

Scientists investigated the genomes of three varieties of Brassica oleracea.

What is meant by ‘genome’?

Figure 5 shows the number of genes in Brassica oleracea that are:

found only in each variety

found in two of the varieties

found in all three of the varieties.

How does Figure 5 show that cauliflower and kale are more closely related than cauliflower and cabbage?

Calculate the percentage of the total number of genes in cauliflower that are in kale, but not in cabbage.

Organisms have been genetically modified (GM) for many reasons.

What has been genetically modified to produce a hormone that reduces blood glucose concentration?

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Algae

Bacteria

Viruses

Scientists are researching the production of GM pigs.

Organs from GM pigs could be transplanted into humans.

What is one advantage of using organs from GM pigs instead of using organs from human donors?

Describe how a human gene could be used to genetically modify a pig embryo.

Farmers produce cotton from cotton plants.

Figure 7 shows a cotton plant.

Insects feed on cotton plants.

Cotton plants have been genetically modified to produce a pesticide that kills insects.

Give one advantage to a farmer of growing cotton plants that are able to kill insects.

Bollworms are insects that eat cotton plants.

Most bollworms are killed if they eat the GM cotton.

Some bollworms have a gene that allows the bollworm to eat GM cotton and survive.

The allele for being killed by eating GM cotton is dominant.

The allele for being able to eat GM cotton and survive is recessive.

Two bollworms mate. Both bollworms would be killed by eating GM cotton.

80 offspring are produced.

Some offspring are able to eat GM cotton and survive.

Predict how many of the 80 offspring are likely to be able to eat GM cotton and survive.

You should:

draw a Punnett square diagram

identify the genotypes of the two parent bollworms

identify the phenotype of each offspring genotype

use the symbols: B = dominant allele b = recessive allele

Predicted number of offspring that will be able to eat GM cotton and survive = __________________

The allele in bollworms for being able to eat GM cotton and survive is recessive.

A bollworm may evolve that has a new dominant allele that allows the bollworm to eat GM cotton and survive.

Explain how a new dominant allele emerging would cause a greater problem than the recessive allele that already exists.

The tawny owl is one species of bird.

The tawny owl can have grey feathers or brown feathers.

The colour of the feathers is determined by one gene.

The allele for brown feathers is dominant (B).

The allele for grey feathers is recessive (b).

What is the genotype of a tawny owl with grey feathers?

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BB Bb bb

Two tawny owls mate.

Complete Figure 16 to show the possible genotypes of the offspring.

Figure 16

What is the probability of the offspring having brown feathers?

Use Figure 16.

Tick (✓) one box.

25% 50% 75% 100%

Scientists investigated the effect of climate change on the number of tawny owls with grey feathers and with brown feathers.

The investigation took place between 1980 and 2020.

Figure 17 shows the results.

The number of tawny owls with brown feathers in the population has increased since 1980.

Give two other conclusions from the data in Figure 17.

Between 1980 and 2020 there was a decrease in the time the area was covered with snow.

The tawny owls with brown feathers are better camouflaged from their prey when there is no snow.

Explain how the increase in the number of tawny owls with brown feathers occurred through the process of natural selection.

Some mosquitos can transmit malaria.

Describe how a mosquito transmits malaria.

Scientists discovered a population of mosquitos living in the tunnels of the London Underground train system.

The mosquito ‘ C. pipiens ’ entered the tunnels when the London Underground was being built in the 1800s.

Some mosquitos were trapped in the tunnels.

Table 6 gives information about C. pipiens mosquitos.

Suggest one reason why the mosquitos living in the tunnels stay active all year round.

Some scientists believe that the mosquitos living in the tunnels have evolved into a new species.

Name the process that causes evolution.

Explain how the mosquitos living in the tunnels could have evolved into a different species from those living above ground.

Most female mosquitos feed on the blood of animals before laying their eggs.

Figure 9 shows the change in the body temperature of a female mosquito while feeding on blood.

Mosquitos control their internal body temperature by homeostasis.

The optimum internal body temperature of mosquitos is 22 °C.

Explain why mosquitos can only feed on blood for a short time.

This question is about the evolution of cats.

Felis lunensis is an extinct cat that lived approximately 2.5 million years ago.

What is the genus name of the cat Felis lunensis ?

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Cat

Felis

Lunensis

Scientists believe that modern-day cats have evolved from Felis lunensis.

How did modern-day cats evolve?

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By cloning

By genetic modification

By natural selection

Give one type of evidence scientists can use to show that modern-day cats have evolved from Felis lunensis.

Scottish wild cats can breed with domestic cats to produce offspring.

The offspring is called a hybrid cat.

Figure 9 shows a Scottish wild cat, a domestic cat and a hybrid cat.

The hybrid cat has inherited genes for different characteristics from both parents.

How has the hybrid cat inherited genes from both parents?

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By genetic engineering

By mitosis

By mutation

By sexual reproduction

Which chemical are genes made from?

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Cellulose

DNA

Lipid

Protein

Give one characteristic that the hybrid cat has inherited from the Scottish wild cat.

Use Figure 9.

Give one characteristic that the hybrid cat has inherited from the domestic cat.

Use Figure 9.

Scientists have investigated the populations of Scottish wild cats and hybrid cats.

Cats hunt for prey at night.

Suggest one reason why scientists find it difficult to identify the type of cat seen at night.

Figure 10 shows where Scottish wild cats and hybrid cats were seen in Scotland in 1987 and 2008.

Describe three differences in the populations of cats between 1987 and 2008.

Use Figure 10.