>What is the dominant life form on Earth? How do we decide this? Is this life form better than others? Posted on March 17, 2010 by thebigqs 7 comments Share this:TwitterFacebookLike this:Like Loading... Related Philosophy Science
>I think bacteria is the most dominant lifeform.In terms of numbers humanity is far from the most numerous. Microfauna, specifically the nematodes (sometimes known as roundworms)measure about 1-2mm in length and supposedly cover almost every inch of land and sea. They supposedly account for 90% of life on the ocean floor.But people are wrong even to declare nematodes as the most numerous life form for bacteria outnumber them.In terms of ability to survive again bacteria trumps the lot. As the most numerous, and one of the quickest evolving lifeforms bacteria have come to adapt to every type of habitat on the planet. They even live on us in huge numbers. We usually say humanity is the strongest species because of our intelligence. But has that intelligence let us dominate bacteria? No. We actually need some bacteria to survive, and hence it seems they are really the dominant ones.But this is what I think is their strongest argument: they can survive the Earth's destruction. If we learnt that the Earth was going to be destroyed tomorrow we would unfortunately be faced with certain destruction. We have the technology to get a few people off of the planet but to do what? We do not have the technology to reach another planet, and nor do we know where we could go to find one that would be habitable. Bacteria on the other hand would simply form a spore, and kind of 'hibernate'. It could actually do this forever! Only when it found another place with liquid water would metabolism re-occur. See the quote below:In space you find a speck of matter too small to be seen with the naked eye. "It is a bacterial spore. The spore betrays no overt signs of life. Encased in a thick protective coat, shrivelled, dehydrated and dormant, its very molecules have almost ceased to move, so intense is the cold. It has already been exposed to enough radiation to kill a human being a thousand times over. Yet this spore is not dead, strictly speaking. Nor can it really be considered alive; it does nothing but wait. It may wait a billion years, it may wait forever. But there is an infinitessimal chance that one day the spore will reach a planet with liquid water. Then suddenly, after a thousand millenia of undistrubed torpor, the spore will return from the dead. Its bacterial soul will begin to stir, genetic memory banks will warm up, metabolism will restart. The bacterium will live life fully once more."Taken from Paul Davies, The Origin of Life, Pg 204And what's more I'm not just a lone lunatic writing about this. Stephen Jay Gould, who died in 2002, said that we should rename the current age "the age of bacteria" due to the fact that this species so thoroughly outnumber all others in both sheer numbers, and in variety. In fact in comparison humanity occupies only a remote, peripheral branch of the tree of life.What I find most interesting about all of this is the resistance of bacteria to conditions in space could even be used to argue that life never begun and simply always was!
>Unquestionably, bacteria! The most successful living organism known to man…. ever!
>yea it is very hard to stop them from multiplying and they are much more succesful than the humans
>That's pretty amazing. Not sure about the ethical dimensions of the second part of the question (are any forms of life 'better' than others? No – life is life) but I'm not going to argue with any of what you've said. Amazing.
>Thanks, yes I agree about the second part. I just put it there to provoke a response. Although your statement that "life is life" actually brings up some interesting questions anyway.Firstly there's the obvious thing to say that humanity tends to judge itself as being better than all other species. If you say that all life is equal then don't you have to back it up? It's similar in my mind to statements about the equality of all people. We say all are equally entitled to certain rights and yet only mean people within a certain geographical location. So saying that all life is equal would require revolutionary new laws to protect wildlife.Next there's the more difficult question: what is life? A friend once asked me what I thought life was. At the time I hadn't given it a huge amount of thought and so I simply responded with what I'd been told at school. He asked "are animals alive?" I said yes. He asked "are insects alive?" I said yes. He asked "are plants alive" I said yes. He then told me to think about what all these things had in common that required them to be defined as life. Biology would say that common feature was the ability to reproduce. But then he told me that there were strings of plasma in space that reproduced in a very 'lifelike' manner. So are they alive? Could we not say that we should treat ourselves with higher regard than we do strings of plasma?
>Interestingly if you take your total weight, the greater mass of what our bodies constitute is not in fact human it is bacterial in origin.I did hear that viruses are also prevalent although do they constitute a life form?
>That's very interesting. Thanks for commenting. About viruses it's really an opinion question seen as no one can agree on what life actually should be defined as. Viruses have genes and do replicate. Yet they can only replicate inside the cells of other living organisms. They do not have a cellular structure, nor have their own metabolism. So in scientific terms they can be classified either way. Yet if we take what we commonly think of as an element of life in us, our feelings, then neither bacteria nor viruses are actually alive. It really depends on your viewpoint.