4 points to Darwins theory of evolution?

Answer 1

I presume the questioner requires 4 points of information about evolution.

Four brief points are;

1. Evolution is driven by natural selection

2. The base unit of variation is the gene

3. Charles Darwin was the original propounder of evolution

4. Comparative anatomy and the fossil record can give clues to the evolutionary of today's extant organisms

Four points is scarcely enough, so below is a little more background.

Charles Darwin formulated the theory of evolution, suggesting natural selection as its driver. He delineated his ideas in On the Origin of Species in 1859.

These days the theory of evolution gleans insight into the evolution of species by examining fossils, dating fossils, comparing anatomies and comparing nucleic acid sequences.

The Theory of Evolution has managed to get this far in tracing the history of life.

Life started in the ocean in the form of the simplest single cells. A likely theory is life started around hydrothermal vents. But whatever the abiogenetic origin of life, as soon as it could be defined as 'life' it began to evolve by nucleic acid mistakes in replication and mutations as such.

Eukaryotic life branched from the main clade of life billions of years after the first life.

The earliest animals were jellyfish and worms and sponges. Note that the sponge species today are not the same as those of the Precambrian Era. That is not how evolution works. The following illustrates, as a diversion, common misconceptions about evolution;

Humans evolved FROM chimpanzees

This is an incorrect statement. Chimpanzees are extant. Humans are extant. It was a human-chimpanzee common ancestor a couple of million years ago that humans and chimpanzees evolved FROM. It is due to the recentness in time from the divergence from the common ancestor of human and chimpanzee that the two are so anatomically and genetically similar.

Thus, in the case of sponges - those sponges extant today are not the original sponges of the world. Sponges today evolved from the same common ancestor as humans, but this common ancestor was billions of years ago. This great time span has given time for animals to diversify and become more complex, explaining the complexity and vast phenotypic differences between sponges and humans. Sponges exist today as the spongeform (which was/is so simple that it could develop first of all among the animals) has been conserved throughout time (since their common ancestor), while the other offbranches - those that may have lead to echinoderms or annelids or sea squirts- changed within their own clades and since they were more complex than sponges, develped later.

All life has a common ancestry. There was once a bacteria-archaebacteria-eukarya common ancestor. That was the first cell or couple of cells of all life. Evolution works by common ancestry. (We can trace this by modern phylogeny and taxonomy, grouping everything into their own groups called monophylies).

Finally, a point on complexity. Obviously things have to start out simple and end up complex, or to put it better, to gain greater complexity as time goes on. But evolution's 'goal' is not to gain complexity. Evolution works by natural selection. Selction selects those characterists of organisms that CAN SURVIVE. Simple sponges can survive just as well as complex mammals or insects. So selection allows them to continue to exist.

Evolution does not seek intelligence either. Intelligent organisms can simply survive a little better than a lot of other things. Intelligence is simply an attribute that allows organisms that acquire it to survive being weeded out by selection.

In short evolution has no goal at all, which is why 'goal' is in inverted commas above.

Still, admiring all species that survive today, that selection allows to survive because they CAN SURVIVE, one can still identify all species' beauty; Darwin's 'forms most beautiful'.