Variation & Survival Advantage
Use evidence to explain how variations in characteristics among individuals of the same species may provide advantages in surviving, finding mates, and reproducing
What a learner can do afterwards
- Explain that variation within a species means some individuals have traits better suited to their environment
- Give examples of advantageous variations (e.g. camouflage, speed, drought resistance in plants)
- Connect variation to survival advantage: individuals with beneficial traits are more likely to survive and reproduce
1 · Read
You know young living things inherit traits from parents yet no two look exactly the same. Look closely at a group of rabbits in the wild. They are the same species, but they are not identical. Some run faster than others. Some notice danger sooner. This kind of difference is called variation, and it can decide which rabbits stay safe.
A gray, speckled moth lands on tree bark and is hard to see. A solid black moth lands on the same bark and stands out. A hungry bird finds the black moth first. The gray moth's coloring is a variation that helps it survive, because camouflage makes it harder to catch.
Surviving is only part of the story. A helpful trait can also help an animal find a mate and have young that inherit the same trait, so the trait keeps helping the next generation too. A plant that needs less water can keep growing in a dry summer.
Individuals in a species have different traits, and traits that help them survive and reproduce give them a survival advantage.
The rewritten reading was written for this dataset.
More to read
Key points: Natural selection
Look closely at animals of the same kind, like a group of beetles or a flock of birds. You will notice they are not all exactly the same. Some are a little bigger, some run a little faster, and some have slightly different colors. These differences are called variations, and they come from tiny differences in each animal's genes.
Some variations help an organism stay alive in its home. These are called advantageous traits. A rabbit with fur that matches the grass is harder for a fox to spot. A deer that runs a little faster can escape more easily. A plant that needs less water can keep growing in a dry summer.
Organisms with helpful traits are more likely to survive, find mates, and have babies. Their babies often inherit those same helpful traits. Over many, many generations, the helpful traits become more common in the whole group. This slow process is called natural selection, and it is one way living things change over time.
Helpful traits across generations
Members of one group of rabbits, birds or flowers can differ from each other, for example in fur colour or beak shape. Some traits pass from parents to their young.
Often, more young are born than there is food, water or space for. Living things then compete for what they need.
An inherited trait may help an individual survive in its surroundings and have more young. Its young may inherit that trait too. Over many generations, helpful traits can become more common in the group, or population. This change is called evolution by natural selection. This can happen even when there is enough food, water and space, if inherited differences help some living things survive or have more young.
Activity: Observing Variation
Here is a science activity you can try. Pick one kind of living thing, like dandelions in a park or pigeons in a square. Look carefully at several individuals from that one species.
What differences can you spot? Maybe one plant has longer leaves, or one bird has slightly darker feathers. Write down or draw what you notice.
No two individuals of any species are exactly alike. Even when they look very similar, tiny differences in their genes make each one unique. These differences are called variation, and variation is what powers the process of evolution. If every individual were exactly the same, there would be no helpful traits to pass on.
2 · Watch
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Where it sits
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Optional connections
Where this leads
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