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The basic idea behind the theory of evolution is that different species have developed over time from other life forms

The Earth is about 4.5 billion years old and there is scientific evidence that life on Earth began more than three billion years ago [1]

Natural selection is now the most widely accepted idea of how the theory of evolution occured

The process

• The difference and variation that occur naturally within a species are caused by the difference in their genes

• The better the characeristics are adapted to the enviroment, the larger the chances of survival. The genes are then more likely to be passed down to the next generation

• The characteristics that are less adapted for survival in a particular enviroment are less likely to be passed down to the next generation because it decreases the chances of survival

• Repeat the process for multiple generation until you aquire the 'perfect specimen's



Evolution in bacteria

Over time, bacteria can become resistant to certain antibiotics (such as penicillin). This is an example of natural selection.

In a large population of bacteria, there may be some that are not affected by an antibiotic. These survive and reproduce - producing more bacteria that are not affected by the antibiotic.

The development

• Random mutations take place in the genes of bacteria cells

• Some of the mutations may protect the bacteria cell from the effects of certain antibiotics

• The bacteria that do not have the mutation die or are unable to reproduce when an antiobiotic is present

• The bacteria that do have the mutation then reproduce with less competition and pass down the mutated gene

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