Evolution

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What is the theory of evolution?
More than 3 billion years ago, life of Earth began as simple organisms from which all the more complex organisms evolved.
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What does looking at the similiarities and differences between organisms allow us to do?
Classify them into groups.
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Describe a difference between plants, animals and microorganisms.
Plants make thier own food & are fixed into ground; animals moved about & can't make own food; microorganisms are different to both the latter, e.g. bacteria are single-celled.
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What does studying the similarties and differences between organisms also allow us to do?
Understand how all living things are related (evolutionary relationships) and how they interact with each other (ecological relationships).
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Describe one aspect of evolutionary relationships (similarities).
Species with similar characteristics often have similar genes because they share a recent common ancestor. They often look alike and tend to live in similar types of habitat, e.g. whales and dolphins.
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Describe another aspect of evolutionary relationships (differences).
Genetically different species sometimes look alike too. E.g. sharks and dolphins look similar because they've both adapted to living in the same habitat. But they're not closely related - they've evolved from different ancestors.
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Describe another aspect of evolutionary relationships (trees).
Evolutionary trees show common ancestors and relationships between organisms. The more recent the common ancestor, the more closely related the two species.
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Describe one aspect of ecological relationships (similiarities).
If we see organisms in the same environment with similar characteristics (e.g. dolphins and sharks) it suggests they might be in competitioon (e.g. for the same food source).
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Describe one aspect of ecological relationships (differences).
Differences between organisms in the same environmentt (e.g. dolphins swim in small groups, but herring swim in giant shoals) can show predator-prey relationships (e.g. dolphins hunting herring).
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Describe the first stage of natural selection.
Individuals within a species show variation because of the differences in their genes.
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Describe the second stage in natural selection.
Individuals with characteristics that make them better adapted to the environment have a better chance of survival and so are more likely to breed successfully.
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Describe the third stage in natural selection.
The genes that are responsible for the useful characteristics are more likely to be passed on to the next generation.
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What is a mutation?
A change in an organism's DNA.
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How can mutations be beneficial?
They can produce a useful characteristic, which may give the organism a better chance of surviving and reproducing.
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What is likely to happen to this beneficial mutation?
Passed on to future generations by natural selection.
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Over time, what then happen to this beneficial mutation?
It will accumulate in a population, e.g. some species of bacteria have become resistant to antibiotics due to a mutation.
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Other cards in this set

Card 2

Front

What does looking at the similiarities and differences between organisms allow us to do?

Back

Classify them into groups.

Card 3

Front

Describe a difference between plants, animals and microorganisms.

Back

Preview of the front of card 3

Card 4

Front

What does studying the similarties and differences between organisms also allow us to do?

Back

Preview of the front of card 4

Card 5

Front

Describe one aspect of evolutionary relationships (similarities).

Back

Preview of the front of card 5
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