The common pipistrelle bat is found in the United Kingdom and lives in open woodland, hedgerows, and farmland.

The table below shows some of the adaptations of the common pipistrelle bat. 

Place a tick in the appropriate boxes to show whether each adaptation is anatomical, behavioural or physiological. 

Explain how a reduction in metabolism allows bats to survive over winter. 

Suggest how wings help the common pipistrelle bat to survive. 

Many organisms produce mating calls.

Explain why mating calls may be advantageous for some organisms. 

Peppered moths, Biston betularia, are a species of moth that live in England, Europe, and in North America.

Until the Industrial Revolution, these moths were typically pale in colour with black spots, although they were found in a variety of shades.

As the Industrial Revolution reached its peak, the air in London became full of soot and the once-white trees and buildings that moths rest on became black.

Over the course of a few months, dark moths started appearing in London and lighter moths became scarce.

State the type of adaptation represented by the colour of the peppered moth. 

Explain why pale peppered moths may be at a disadvantage in a habitat made up of black trees.

Describe and explain how a dark peppered moth may have evolved from a paler ancestor. 

Once the peak of the Industrial Revolution passed, lighter peppered moths made a comeback.

Explain why. 

The long-tailed widowbird, Euplectes progne, is a species of bird found in areas of open grasslands, marshes, and tall grasses.

During the non-breeding season, both male and female long-tailed widowbirds look the same.

However, from October to April, breeding males develop an exceptionally long tail (up to 50 cm).

The diagram below shows a male long-tailed widowbird during breeding season. 

Suggest one reason for male long-tailed widowbirds to develop a long tail during mating season. 

A group of scientists measured the tail length of male long-tailed widowbirds over a period of years.

Their results are shown in the diagram below.

Name the type of selection shown in this graph, and explain why this selection affected the frequency of alleles in the population of long-tailed widowbirds. 

Another group of scientists investigated the genetic diversity within a population of long-tailed widowbirds. 

Explain what is meant by the term genetic diversity. 

Describe and explain how selection will affect genetic diversity of long-tailed widowbirds. 

The black-capped chickadee is a small, non-migratory songbird that lives in deciduous and mixed forests.

A group of biologists studied the nests of a population of black-capped chickadees.

For each nest, they recorded the number of eggs and the number of young that survived from the nest.

Their results are shown below. 

What type of selection is shown in the graph above? 

Describe the evidence for your answer to the question above. 

Explain why black-capped chickadees that lay fewer than 3 eggs or more than 11 eggs per nest are at a selective disadvantage. 

Other than genetics, name one other factor that may influence the number of eggs laid by a black-capped chickadee.

Farmers used to give livestock food with added antibiotics. 

Suggest why farmers used to give antibiotics to their livestock. 

The use of antibiotics in farming is now banned in many countries.

Explain why. 

One of the first widely used antibiotics was penicillin.

However, strains of bacteria are increasingly becoming resistant to penicillin.

Describe how a population of bacteria can become resistant to penicillin. 

The cheetah, Acinonyx jubatus, is a member of the cat family, Felidae.

Cheetahs have a lightweight skeleton, an aerodynamic body frame and long leg and foot bones. 

Explain how a lightweight skeleton allows cheetahs to survive. 

Cheetah populations show less intraspecific genetic diversity compared to other members of the Felidae family.

Some scientists believe that a recent genetic bottleneck has caused this lack of diversity.

Explain how a genetic bottleneck can lead to low genetic diversity. 

Other than a genetic bottleneck, suggest two reasons why cheetah populations might show low levels of genetic diversity. 

Apart from genetic factors, what other type of factor causes variation within a species?