Hi, I wanted to know, if all life evolved from a single beginning organism, when did the split between plant and animal happen. Or did plants and animals evolve from differing origins, and if so how does the theory of the early primordial soup creating 2 distinct organisms instead of just one effect the theories behind evolution? I've been curious about this for a while as all articles and lectures seem to only talk about the fauna side of evolution and not the link between flora and fauna.
It is believed that the first sets of molecules began in water. And they had at the time no DNA but only RNA. When clumps of those fell apart, they combined with other parts of other clumps..... the beginning of reproduction. And reproduction is necessary for life. Sooooo you could say that the first things to reproduce were molecules of RNA. Thus this very primitive system of reproduction made these molecules the inventors of "life". The chances of this happening were billions and billions to one. BUT, there were billions and billions of molecules and billions and billions of years, and this needed to happen only once, and thus, tho the odds appear insurmountable, these billions made it a certainty. Remember, it needed to happen only once, and "life" was off and running.
The first living things appear to be things such as we still have today...stromatolites... Google them.
And we know as well, that when the reproduction got a bit more complicated, that DNA evolved. And you have sections of DNA in exactly the same order as so spiders, and fish, and oak trees and wheat plants. There are certain combinations that are necessary for life.....all life. And scientists have divided life into three great Kingdoms....Plants, Animals and Protists. Look them all up
That there are three different types of organisms (not two) simply shows that evolution is a dynamic process...continuing all the time even today. (More on this later*)..
Everything alive on this planet is related to every other thing alive on this planet
There are three things that drive evolution.... time, death, and mutations. Time is needed for the good and bad mutations to become part of the genome of some plant, animal or protist. And if nothing ever died, the mutations would be worthless. And what ever had evolved in the beginning, would still be the only stuff on this planet.
I'll add some youtube videos in this so that you can get the entire picture.
As an example as to how all animals are related, all animals that are bilateral have a set of HOX genes, and only bilateral animal have them... people all mammals, scorpions, spiders, etc, but since starfish, octupi and hydra etc., are NOT bilateral, they do not have these series of HOX genes. (google HOX genes).
At this point in the long history of evolution, any mutations are usually bad, or even lethal, and those that carry them usually are disadvantaged, or do not survive to adulthood to pass on those genes. There are lots of great articles in Wikipedia, and lots of charts and graphs that show the walk backwards from today, to the beginning of life. And if you wish a great read, do indeed read "The Ancestor's Tale" by Richard Dawkins. Pay attention. It's really a great book.
For example, thru some surviving DNA alone, we know that birds are the descendants of dinosaurs. In fact many dinosaurs had feathers.
*Some recent examples of mutations that turned out to be fabulous:
1. The Morgan Horse. In the 1700's in the US. The first Morgan horse was called Figure. He was not a big horse, but he was unlike his parents. He could pull a heavy plow all day, then, run match races against fresh horses in the evenings, and win. (Google him.... Horse + Justin Morgan) To this day, all Morgan horses are usually bay in color, have a muscular neck, and stamina beyond the average.
2. The Red Delicious Apple. I'll let you google the history on this one.
However, as stated previously, most mutations that occur today are deleterious.... two headed mice, or two headed snakes, blood disorders that are difficult to treat in humans and animals. Most always a paint horse that is almost all white, has a digestive tract, that is not continuous.... it ends somewhere in the esophogus, and does not continue. These foals die. The gene for this is called a lethal gene. Things that are conjoined twins, in nature do not live long. Because of modern medicine, many of them now can be separated, but this has been only in the last 70 years or so. The eons and eons before this time, conjoined twins of any animal, were regarded as a curse upon a family from the gods.
Some videos you may find interesting:
2. https://www.youtube.com/watch?v=XGK84Poeynk. In this one, Richard Feynman PH. D in physics, is playing the bongos. Interestingly, he was just hugely brilliant, and as well interestingly, he played those bongos at a strip joint not far from his office at Cal Tech. He was part of the bunch that worked on the atomic bomb in the 1940's, and as a result died of the effects of radiation, at a rather young age. He as well, discovered how the Challenger blew up as it as barely off the pad at Cape Kennedy. Google this too. (Challenger disaster... what caused it)
When you see that all of life is related, and that all of life can reproduce, at least at the cellular level, life is utterly amazing. So little of any of this was known even 200 years ago. Gods were responsible for diseases, and horrible things like earth quakes and volcanoes.... today? Gods are an ever increasing glob if scientific ignorance that gets smaller and smaller as each day goes on.
3. Try this one too"
4. Take a look as well at the website, boneclones.com. This outfit copies fossils for use in museums that wish to have, say a T. Rex, but there just aren't all that many. Expensive? Yes. But notice how all the primate heads look pretty much alike. Humans are just an ape...a naked one. We are about only 2% different in our DNA than our nearest living relative, the chimp.
5. Watch some of the other youtube videos under "symphony of science."
And there would have been no evolution on this planet or any other had not there been super-novae....stars that exploded and spewed out the necessary chemicals for life.... iron, copper, and most of all, carbon.
Humans are just specs on a planet that is just a spec in a solar system, that is just a spec, in a galaxy, we call the Milky way, that is just a spec in the entire universe. There are more galaxies in the universe than there are grains of sand on all the beaches on this planet. Are you beginning to see how utterly small this tiny planet is? And that humans are insignificant in the picture of the entire universe?
Before 1923.... not all that long ago.... the Universe was just our Milky Way. That was it.... The Milky Way. Nothing else. Then with the invention of the Hubble Telescope, things opened up, and we are discovering more and more about not only life on this planet, but everything else!!!!
Bottom line? With out supernovae, there would have been no evolution on this planet.
If you have questions, feel free to write...