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Year 9

Natural selection

I can explain how variation and competition lead to the natural selection of individuals with the most helpful characteristics.

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New

Year 9

Natural selection

I can explain how variation and competition lead to the natural selection of individuals with the most helpful characteristics.

Download all resources

Share activities with pupils

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Lesson details

Key learning points

Variation within a population of a species means some individuals are better adapted to compete and survive.
The fittest (better adapted) individuals are more likely to survive to reproduce.
These individuals are more likely to pass on heritable, advantageous features to their offspring.
This is natural selection, and causes the advantageous features to become more common in each generation of offspring.
Changes in environmental conditions, including changes caused by humans, can affect natural selection.

Keywords

Variation - Variation is the term for differences between individuals of the same species.
Competition - Living organisms struggle for access to limited resources. This struggle is known as competition.
Fittest - Organisms that are the best adapted to their environment are said to be the fittest.
Reproduction - Reproduction is the process of making offspring.
Natural selection - Organisms that are better adapted to their environment are more likely to survive, reproduce and pass on their genes to their offspring.

Common misconception

Students often think that advantageous traits are due to an organism choosing to change itself in order to be successful.

This lesson uses CfUs in order to explore and deconstruct this misconception.

Be careful when describing the process of natural selection to not use language like "The organism adapted itself in order to survive" this is incorrect. Adaptations that happen to be advantageous occur randomly and are not decided by the organism, then are maintained by natural selection.

Teacher tip

Licence

This content is © Oak National Academy Limited (2024), licensed on Open Government Licence version 3.0 except where otherwise stated. See Oak's terms & conditions (Collection 2).

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Starter quiz

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6 Questions

Q1.

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

fat increases heat loss from the hump

Correct answer: 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

Q2.

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

Correct Answer:broad,maximises the absorption of light

maximises the absorption of light

Correct Answer:chlorophyll,a chemical that absorbs light

a chemical that absorbs light

Correct Answer:thin,allows quick gas exchange

allows quick gas exchange

Q3.

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?

they are all equally well adapted

they are competing for mates

Correct answer: there is not enough food

maggots only live for a few days

Q4.

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

Correct answer: food

light

Correct answer: mates

pollinators

seed dispersers

Q5.

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

Correct answer: greasy fur helps it repel water to dry quickly

large ears to decrease heat loss

short coat to decrease heat loss

Correct answer: pads on feet help insulate their feet on the cold ground

Q6.

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

1 - Having less chlorophyll means these leaves produce less food.

2 - Plants with less food grow more slowly.

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

4 - Without enough sunlight plants die.

Exit quiz

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6 Questions

Q1.

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?

competition

natural selection

Correct answer: variation

Q2.

Match the words with the correct definitions.

Correct Answer:competition,living organisms struggle for access to limited resources

living organisms struggle for access to limited resources

Correct Answer:fittest,organisms that are the best adapted to their environment

organisms that are the best adapted to their environment

Correct Answer:reproduction,the process of making offspring

the process of making offspring

Q3.

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

dark variants of the moth were easier for predators to see

Correct answer: dark moths were better camouflaged

soot from the burning coal turned the moths dark

the change was a random event.

Q4.

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

Correct Answer: common, frequent

Q5.

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

caused by the environment.

learned.

Correct answer: inherited.

caused by lifestyle.

Q6.

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.

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

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

3 - These cod are therefore more likely to reproduce.

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

Q3 Marek R. Swadzba/Shutterstock.com