Re: Similarites between past & present environments of Archaea????

hi Greg,

I agree with your teacher, class interaction is good!

This is an interesting question - let me give you a few pointers. First, what are Archaea? They are single-celled microorganisms (prokaryotes), similar to but distinct from Bacteria. In fact, they make up a third domain of life alongside Bacteria and Eukarya (Eukarya are organisms with organelles like you and me, animals, plants, amoebae and so on).

What kinds of environments do Archaea live in today? All kinds. They are ubquitous (everywhere) in the environment - found in the oceans, the guts of cows, on your teeth, in hot springs.

You have been asked this question for a reason. Many Archaea are what are known as extremophiles - they live in environments that we would consider extreme, such as boiling water, icy pools in Antarctica, very salty or alkaline lakes and acidic waste dumps. We think that when the ancient earth was a more hostile place, organisms like Archaea might have been amongst the first forms of cellular life. We also think that were microbial life to be found outside of Earth, for example on Mars, the organisms there might be rather like Archaea. But it's important to realise that not all Archaea are extremophiles and not all extremophiles are Archaea. There are also Bacteria and even Eukarya that live in hostile environments. You might also want to do some internet research to find out what people think the early earth was like - there are differing opinions.

Finally, there are quite a few websites on Archaea and I think if you explore the links thoroughly, you will find some information about your question. I hope MadSci don't mind if I promote my own site, which is called ArchaeaWeb and has quite a few useful links.