A general explanation that applies to a large number of situations. Theories are widely accepted by scientists because they have been extensively tested and evidenced.

The process by which the characteristics of species change over many generations, sometimes becoming new species.

Organisms that are better adapted to their environment are more likely to survive, reproduce and pass on their genes to their offspring.

Evolution

Science

Fossils show that species change over time

Understanding time scales

Adaptations

Competition

Heritable variation

Natural selection

A model of natural selection

Pupils will learn that the fossil record provides evidence of evolution from common ancestors through transitional species to modern species, and that the theory of evolution by natural selection can be used to explain phenotypic changes in populations of species over generations.

Pupils learned that variation (differences in the features of individuals of the same species) can be caused by environmental and genetic factors.

This unit explores variation within and between species, competition, and natural selection. It focuses on asking questions, making predictions, planning scientific enquiries, and testing hypotheses. It also covers analysing results, explaining findings, and identifying new questions that arise.

Adaptations, competition, natural selection and evolution

Which of the following provides evidence that the characteristics of species change over many generations?

The characteristics of species change over many generations, sometimes taking thousands of years. What word do scientists use to describe this process?

It is a general explanation that applies to a large number of situations.

It is just a best guess that could be true.

It is widely accepted by scientists because it has a lot of supporting evidence.

Which of these are features of a scientific theory?

Chimpanzees and humans are the same species.

Chimpanzees and humans share a common ancestor.

Humans have 99% of their DNA in common with chimpanzees.

Which of the following statements are true?

Not evolution (it’s a change within an individual’s life)

Evolution (it’s a change in the features of a species)

Match each example to its correct description.

Andeep: “When the first rats became resistant it just happened at random.”

Jun: “All of the rats learned to be resistant from the ones that were.”

Laura: “Resistance to the poison became common because of natural selection.”

Sam: “Rats decided to adapt so they could resist the poison.”

Warfarin is a poison used to kill rats. Over many generations, resistance to warfarin has become common amongst rats and it no longer kills them. Who has correct ideas that help to explain this?

There are differences between these four individuals of the same species of giraffe. What is the scientific term for these differences?

Giraffes eat leaves from trees, but there is a limited number of leaves. The giraffes are in {{}} for the leaves.

Which giraffe has an advantage in the competition for food?

Neither giraffe is well adapted to survive

The two giraffes are equally well adapted to survive

Which giraffe is the best adapted to survive?

Which giraffe would scientists describe as the fittest?

There was variation between the giraffes.

Long neck giraffes were better adapted to compete for food, so had an advantage.

Giraffes with longer necks were more likely to survive and reproduce.

They were more likely to pass on the genes for a longer neck to their offspring.

Longer necks became more common in each new generation of giraffes.

Put the statements in order, to explain why giraffes with longer necks became more common in the population.

Starter Quiz

There are differences between these four individuals of the same species of giraffe. What is the scientific term for these differences?