Evidence for evolution

Figure 6 shows the bones in the limbs of a bird and a whale.

The bird and the whale have evolved from a common ancestor.

Give one way the structure of these limbs provides evidence for this evolution.

Charles Darwin developed the theory of evolution by natural selection.

Which scientist worked with Darwin on the theory of evolution by natural selection?

DNA is found in bones and stem cells.

Suggest one reason why DNA is found in bones.

Describe how stem cells help animals to grow.

Scientists have transplanted stem cells into the retina of the eye.

Name one type of light sensitive cell found in the retina.

Explain one reason for transplanting stem cells into the retina.

The book ‘On the Origin of Species’ was published in 1859.

This book describes the theory of evolution.

Which scientist wrote this book explaining his theory of evolution?

Which statement is supported by this theory of evolution?

One chapter of this book discusses pentadactyl limbs.

Figure 5 shows the bones of the pentadactyl limbs of three mammals.

Describe one difference between the humerus of the whale and the humerus of the human.

Describe one difference between the phalanges of the horse and the phalanges of the human.

Another chapter of the book discusses how the shape of bird beaks has evolved on different islands.

Figure 6 shows two species of finch from two different islands.

(Source: © Kristel Segeren/Shutterstock)
(Source: © Maurizio De Mattei/Shutterstock)

Species A
Species B

Figure 6

These two species of finch evolved from a common ancestor that had a similar shaped beak to species B.

Beak shape is related to the food that the finches eat.

Describe how the thinner beak of species A is a result of evolution.

Alfred Russel Wallace travelled around Malaysia during the 1800s and wrote to Charles Darwin about the animal species he studied.

His main conclusions were very similar to those of Charles Darwin and they both contributed to the current understanding of evolution.

Describe the theory of evolution by natural selection.

Wallace and Darwin did not always agree.

Darwin believed that male birds have feathers that are brightly coloured to make them more attractive to female birds.

Wallace thought that female birds have feathers that are less brightly coloured so they are more likely to survive.

Explain why having feathers that are less brightly coloured increases the survival rate of females.

Suggest why it is more important for the survival of the species that the survival rate is higher in female birds than in male birds.

Figure 7 shows the limbs of five animals.

Describe how the structure of these limbs provides scientists with evidence for evolution.

7 (a) Figure 14 shows the limbs of some animals.

Figure 14

Describe how these limbs provide evidence for evolution.

(b) Prickly pear cacti are weeds that grow in many countries. Insects have been used to limit the population of prickly pear cacti. Figure 15 shows some insects on a prickly pear cactus.

(Source: © Catherine Eckert/Shutterstock)

Figure 15

(i) Which is the name of this method of limiting the population of weeds?

(ii) Give two benefits of using insects, rather than chemicals, on prickly pear cacti.

* (c) Some crop plants have been genetically modified to be resistant to insect pests. Explain the advantages and disadvantages of producing genetically modified crop plants.

(a) Figure 13 shows the pentadactyl limb of a bat and a cat.

Describe the reasons why the anatomy of the pentadactyl limb suggests that bats and cats evolved from a common ancestor.

Genetic analysis also provides evidence for evolution.

Scientists can sequence genes from different organisms.

Describe how this type of genetic analysis provides evidence for evolution.

Mendel’s research on pea plants showed that genetic traits are inherited.

Which term is used to describe the expression of traits in an organism?

Mendel crossed pea plants that produced round seeds with pea plants that produced wrinkled seeds.

All the offspring produced round seeds.

He then crossed these offspring with each other.

Some pea plants in the next generation produced round seeds and the others produced wrinkled seeds.

Explain how this showed that some inherited traits are not expressed in an organism.

Duchenne muscular dystrophy is a recessive sex-linked genetic disorder. This disorder causes muscle weakness.

Figure 14 shows the inheritance of Duchenne muscular dystrophy in a family.

State and explain the phenotype of person Z.