Human evolution

Figure 7 shows the times when Homo sapiens (modern humans) and some of their ancestors are thought to have lived.

Which term is used to describe changes in species over time?

Estimate the length of time Homo habilis is thought to have lived on Earth.

Describe two methods scientists used to date the fossils of Ardi or Lucy, as shown in Figure 7.

The ancestors of modern humans used selective breeding to improve the plants they used for food.

Complete the sentences using words from the box.

Selective breeding involves choosing parents with

desirable_........ .

The best offspring are bred together and this process is repeated over

many_........ .

Suggest one feature of a banana that could be improved by selective breeding.

The DNA of fruit can be modified to produce new varieties.

Figure 8 shows part of a method used to extract DNA from fruit.

State the purpose of both step 1 and step 2.

State why the cold ethanol was added in step 3.

A report stated that Homo habilis was a hominin species that lived on Earth between 2.4 million years ago and 1.5 million years ago.

State the number of years that Homo habilis lived on Earth.

Fossil evidence suggests that Homo habilis used tools.

State one use of these tools.

Scientists use fossil discoveries to suggest the structure of the whole body.

Lucy is a fossil of the species Australopithecus afarensis.

Describe how the body structure suggested for Australopithecus afarensis is different from the body structure suggested for Homo habilis.

Explain what could have caused the extinction of Australopithecus afarensis.

Figure 6 shows how the three-domain classification system was developed.

Describe the differences between prokaryotes and eukaryotes and why the three domain classification system was introduced.

Figure 7 shows images of two stone tools.

Scientists think that tool A was probably used by Homo erectus around 1.6 million years ago.

Tool B was probably used by Homo habilis around 2 million years ago.

Give one reason, using Figure 7, why scientists think that tool A was used by a more recent human ancestor.

Describe how scientists can date stone tools using information from where the tools were discovered.

Differences in fossilised bones indicate structural changes that have occurred during the evolution of humans.

Describe two structural changes that have occurred during human evolution.

The migration patterns of humans can be tracked by analysing DNA in mitochondria.

Figure 8 shows a mitochondrion viewed using an electron microscope.

At a magnification of 62 000 this mitochondrion has a length of 434 mm.

Calculate the actual length of this mitochondrion.

Give your answer in micrometres (µ m).

Explain why an electron microscope is used to see mitochondria clearly.

Figure 4 shows fossils in different layers of rock.

Which layer of rock is likely to contain the most recent fossils?

Figure 5 shows some stone tools from two different periods of time.

Explain one difference between tool A and tools B, C and D.

Our human ancestors domesticated animals.

Animals were domesticated to use as working animals and to keep as pets.

Use words from the box to complete the sentences.

Animals with the most desirable_........ were bred together.

This is called_........ breeding.

Scientists have analysed the genomes of domestic animals.

Which is the definition of a genome?

Give one advantage of domesticating animals.

Stone tools can be found at sites used by our human ancestors.

Describe how tool P was made.

Figure 4 shows tool Q which was found at the same site as tool P.

A scientist stated that tool Q was made by a more evolved human ancestor than tool P.

Which observation supports this statement?

Tools provide evidence for human evolution.

Use words from the box to complete the sentences.

Evolution is the change of inherited characteristics through

_........ selection.

These changes occur because genes_........ .

Fossils were also found in the soil around tool Q.

Describe two ways that stone tools and fossils can be dated to find out how old they are.

Clostridium tetani is a bacterium that can be found in soil.

It causes the infection tetanus.

Children are vaccinated against tetanus.

Explain why these children do not get tetanus if the bacteria enter their body through a cut in the skin.

Colistin is an antibiotic used to treat infections in the bloodstream.

Some bacteria are resistant to Colistin.

Explain how these bacteria have become resistant to Colistin.

*(c) Figure 15 shows three stone tools found in different layers of rock.

Explain how information from Figure 15 provides evidence for human evolution.