What is Life?

is an excellent book by Paul Nurse (isbn 978-1-788451-40-6)
As usual I'm going to quote from a few pages.

Cells repair these mutations, but they are not completely successful. If they were, all individuals of a species would be identical and evolution would stop. This means the error rate itself is subject to natural selection. If that error rate is too high the information stored by the genome will degenerate and become meaningless, and if errors are too rare, the possibility for evolutionary change is reduced. Over the long term, the most successful species will be those that can maintain the right balance between constancy and change.
Humanity should care about the entire biosphere; all the different life forms that share our planet are our relatives.
Once microbes evolved the ability to photosynthesize, they multiplied, over the millenia, to such an extent that the amount of oxygen in the atmosphere spiked. What followed, between 2 and 2.4 billion years ago, is called the Great Oxygen Catastrophe. All organisms that existed at that time were microbes, either bacteria or archaea, but some researchers think most of them were wiped out by the appearance of all that oxygen. It is ironic that life created conditions that nearly ended life as a whole.
To fuel all of the chemical reactions needed to support your body's trillions of cells, your mitochondria together produce, amazingly, the equivalent of your entire bodyweight in ATP every day!
The life forms that survive natural selection persist because they work, not necessarily because they do things in the most efficient or straightforward way possible. ... This can disturb some physicists who turn their attentions to biology. Physicists tend to be attracted to elegant, simple solutions, and can be less comfortable with the messy and less-than-perfect reality of living systems.
Even plants rely on bacteria found in or near their roots that capture nitrogen from the atmosphere. ... In fact, this is something that, as far as we know, no eukaryote can do for itself. That means there is not a single known species of animal, plant or fungus that can generate its own cellular chemistry entirely from scratch.
Life on Earth belongs to a single, vastly interconnected ecosystem, which incorporates all living organisms.
Biology shows us that all the living organisms we know of are related and closely interacting. We are bound by a deep connectedness to all other life.


No comments:

Post a comment