Variation is the term for differences between individuals of the same species.

Living organisms struggle for access to limited resources. This struggle is known as competition.

Organisms that are the best adapted to their environment are said to be the fittest.

Reproduction is the process of making offspring.

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

Natural selection

Science

Fossils show that species change over time

Understanding time scales

Adaptations

Competition

Heritable variation

A model of natural selection

Evolution

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

Individuals in a population of plants or animals are not all the same. For example, humans have different eye colours. What term do scientists use to describe these differences?

living organisms struggle for access to limited resources

organisms that are the best adapted to their environment

Match the words with the correct definitions.

dark variants of the moth were easier for predators to see

soot from the burning coal turned the moths dark

During the industrial revolution, dark variants of peppered moths became more and more common. Which is the best explanation for this?

Natural selection over many generations causes helpful adaptations to become more {{}} in the population.

For natural selection to happen, characteristics must be ...

Smaller cod are less likely to be caught in the nets.

These cod have an advantage and are more likely to survive.

These cod are therefore more likely to reproduce.

The smaller cod pass the genes for this characteristic on to their offspring.

Humans catch fish called cod using nets. The nets only catch the bigger cod. Smaller cod fit through the holes. Order the steps to explain why small cod are becoming more common in each generation.

not storing fat in the rest of the body allows heat to be lost more easily

the fat in the hump slows heat loss from the hump

Camels store fat in their hump. Why is this a helpful adaptation for living in a hot environment?

Leaves are adapted to contain chlorophyll and be broad but thin in shape. Match each adaptation with its function.

A single female house fly can lay up to 500 eggs. The eggs hatch into maggots which feed on food waste. Why don’t all the maggots survive to become adult flies?

These two male deer (stags) are competing. Which resources could they be competing for?

greasy fur helps it repel water to dry quickly

pads on feet help insulate their feet on the cold ground

Arctic foxes live in the Arctic and are adapted to survive in low temperatures. Which of the following are adaptations of the Arctic fox?

Having less chlorophyll means these leaves produce less food.

Plants that grow more slowly than surrounding plants get less sunlight.

Some plants have variegated leaves, which contain less chlorophyll than normal leaves. Order the sentences to explain why these leaves could be a disadvantage.

Starter Quiz

Camels store fat in their hump. Why is this a helpful adaptation for living in a hot environment?