"What is life" is one of my favorite books. It's packed full of fascinating explanations of how the most basic elements of life came to be.
For example, did you know that sex evolved from cannibalism among single-celled organisms? Quote from p.139:
"Microscopists sometimes witness microbial wrangling in which a hungry cell engulfs a neighbor. But the cells do not always digest what they engulf."
"Harvard University biologist Lemuel Roscoe Cleveland saw cannibalized protists live on the half-devoured. The protists he studied, covered by 9(2)+2 undulipodia, are called hypermastigotes. Normal hypermastigotes, which contain only a single set of chromosomes, live in the swollen hindguts of wood-eating termites and cockroaches. Cleaveland saw the hypermastigotes engulf one another. He noted that once they did, their membranes merged to make them into doubled cells. Most of the doubles died. But Cleaveland also saw that some of these doubled beings reproduced. Although sloppily, a doubled microbial monster would undergo cell division and give rise to another doubled microbial monster."
"Cleaveland saw how thwarted cannibalism could have led to the first set of of doubled chromosomes. Moreover, abnormal cell divisions--a precursor to the meiosis that takes place in our own cells--could restore the merged would-be cannibals to their original single set of chromosomes."
...
"Once upon a time, we think, eating and mating were the same. Terminal microbial indigestion may seem rather unromantic as the source of the human sex drive. But Cleveland's picture of hungry, serendipitously mating hypermastigotes presents a mix of comedy and terror appropriate for the origin of sex."
"What is life?" and "What is sex?" are really interesting books; they made me realize how barren my high school biology classes were. She was a great thinker.
Great example of an idea that was initially widely rejected only to be later widely accepted. How many times does that happen in science?
Seems to me that the biological reality is that bacteria rule the Earth. They always have and always will, before we were here and after we're gone. And it seems at present there is _relatively_ little biotech we can do without the help of bacteria and their amazing junk-free genome. But I could be wrong. Corrections from the experts are welcome.
This is reminiscent of a classic trope used to introduce students to some of the more advanced concepts in evolution.
Which is more evolved: a bacterium or a human?
To answer, you have to consider what it means to be "more evolved". A human has been subject to more branchings on the tree of life, but why does the tree of life branch? Usually because there is a new niche to occupy. And what is evolution? It's the process of exploring new niches and becoming "best fit" for a niche. So, humans have explored more niches in biological evolution, but all the while bacteria have instead continually adapted to become better and better fit for their niche.
Ultimately, the consequence of this is that it would be much easier for humans to be evicted from their niche, or for that niche to move just far enough for humans to no longer be able to cope. So, yes, bacteria will be here long, long after we are gone...
But if you really want to talk about ruling the Earth, well, viruses pretty much have that one in the bag. Go down to the sea with a teaspoon and scoop up some water. You'll have around 1 million bacteriophages (viruses that infect bacteria) in that one spoon.
Aren't bacteria move evolved in a sense? Vertebrae are all almost the same. (Or even multicelled organisms.) Bacteria come with much more diversity in genetics and biochemistry.
In the world of bacteria, there is no need for the SEC, lawyers or fear of liability. It's the fact that their needs are so few - they can seemingly live almost anywhere under almost any conditions - that makes them appear so resilient.
Is it adding features? (to use the software lingo)
Or is it subtracting ones that have no real benefit, striving toward greater efficiency?
Like terse lines of code in a concise, well-written computer program, every bacterial gene seems to exist for one or more reasons. There is no bloat.
I'm biased, but to me bacteria, chloroplasts and mitochondria are life's most amazing machines and the tasks they perform are ultimately life's most important ones.
For example, did you know that sex evolved from cannibalism among single-celled organisms? Quote from p.139:
"Microscopists sometimes witness microbial wrangling in which a hungry cell engulfs a neighbor. But the cells do not always digest what they engulf."
"Harvard University biologist Lemuel Roscoe Cleveland saw cannibalized protists live on the half-devoured. The protists he studied, covered by 9(2)+2 undulipodia, are called hypermastigotes. Normal hypermastigotes, which contain only a single set of chromosomes, live in the swollen hindguts of wood-eating termites and cockroaches. Cleaveland saw the hypermastigotes engulf one another. He noted that once they did, their membranes merged to make them into doubled cells. Most of the doubles died. But Cleaveland also saw that some of these doubled beings reproduced. Although sloppily, a doubled microbial monster would undergo cell division and give rise to another doubled microbial monster."
"Cleaveland saw how thwarted cannibalism could have led to the first set of of doubled chromosomes. Moreover, abnormal cell divisions--a precursor to the meiosis that takes place in our own cells--could restore the merged would-be cannibals to their original single set of chromosomes."
...
"Once upon a time, we think, eating and mating were the same. Terminal microbial indigestion may seem rather unromantic as the source of the human sex drive. But Cleveland's picture of hungry, serendipitously mating hypermastigotes presents a mix of comedy and terror appropriate for the origin of sex."