Different genes control variation - this is because genes control an organism's characteristics.
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How are characteristics controlled by the environment?
The characteristics can be controlled by anything around them such as height - if someone is meant to grow to 6" but is malnourished, they will not grow that high.
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What do mutations do?
Mutations change the sequence of bases in the DNA and chance the characteristics of the organism.
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What can mutations sometime cause?
They can sometime be introduced which changes the characteristics of a species
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What is the theory of evolution?
All of today's species have evolved from simple life forms that first started to develop over three billion years ago.
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What did Charles Darwin come up with?
He came up with the thory of evolution by natural selection as organisms had to compete for resources and that in a species, there is wide phenotypic variation.
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What does natural selection suggest?
It suggests that that beneficial changes would become more common in a species until it evolves.
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Why was Darwin's theory not accepted at first?
There was limited knowledge of DNA and genes and so he couldn't come up with an explanation for why this happens.
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Why was Darwin's ideas controversial?
He released a book on evolution into a heavily religious society and so many wouldn't accept it because it went against the idea of God.
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Who was Jean-Baptiste Lamarck?
He came up with the idea that changes occurred within an organism's life and was passed down to its offspring.
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Why was Lamarck's theory rejected?
His experiments didn't prove his theory whereas the discovery of genes supported Darwin's theory.
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What is selective breeding?
When organisms are selectively bred to develop useful and attractive features.
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What is genetic engineering?
The transfer of a gene responsible for a desired characteristic from one organism's genome into another organism.
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What is tissue culture?
This is where a few plant cells are transferred into a growth medium with hormones and then they start to grow into new plants.
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What is cuttings?
This is where a farmer takes cuts of plants and then plants them for them to grow.
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How are fossils formed?
They're formed when dead organisms sink to the bottom of the ocean and they are covered with sand and sediment over millions of years to become stone.
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Other cards in this set
Card 2
Front
How are characteristics controlled by the environment?
Back
The characteristics can be controlled by anything around them such as height - if someone is meant to grow to 6" but is malnourished, they will not grow that high.
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