Question: how did evelution happen

Michelle Linterman answered on 15 Nov 2012:

Great question, evolution is a very exciting topic.

Evolution needs two things:
First, there needs to be a group of individuals that have different DNA from each other.
Second, there needs to be some sort of environmental factor that can be bad for these individuals.

For example, if you take a group of bacteria living in a Dogs mouth, they are probably quite happy living there, but might cause bad doggy breath. Then – the dog gets sick, and her owner gives the dog bacteria-killing medicine (antibiotics), now most of the bacteria will die because this is the job of antibiotics. BUT if some of the bacteria have a piece of DNA that means they are not killed by the medicine then they will continue to live in the dogs mouth. Then they will make more bacteria, and these new bacteria (like their parent bacteria) will also not be killed by the medicine if the dog is sick again. So the community of bacteria in the dogs mouth has changed, from being mostly killed by medicine to not being killed. This change in the community is what makes up evolution.

If you can imagine that things like this happen again, and again over hundreds of thousands of years, lots and lots of small changes to a community can eventually completely change what the community looks like.

If you have any more questions about this, or are confused about anything, just let us know and we will try and answer as quickly as possible.

Michelle