Hell yea E V O L U T I O N, finally we got there, been trying to come up with a consistent creature lineage for months and I and got it, be showing the first ones next post.
So, let's recap some of what evolution is:
- The process by which different kinds of living organisms are
thought to have developed and diversified from earlier forms during the
history of the Earth.
- The gradual development of something, especially from a simple to a more complex form.
Nice, then let's fix some misinformation about it:
EVOLUTION HAS A GOAL, AND THUS IT "STOPS" WHEN THE SHAPE IT ACQUIRED IS "PERFECT" / EVOLUTION ONLY WORKS AT TIMES OF CRISIS.
No! It doesn't work like that. Evolution has no specific GOAL body-plan, but to shape it in a way to better suit to it's environment. Any given creature/species keep evolving even at "stable" conditions, crocodiles existed for millions of years and maintained a fairly regular shape, but they haven't stopped evolving, evolution doesn't always express in it's phenotype, ie, the part of the genes that are responsible for external features (crests, eye color, skin color, etc.), evolution continues to happen slower and more internally in a "stable" environment, crocodiles will continue to fight bacteria and viruses and develop resistance against them from generation to generation, rates of reproduction and means of reproduction will still be under miss-copying of DNA codes leading to variation, life works this way, because one day or another these variation ponds will be essential for the survival of the species. When a crisis happen, like rapid-changing climate or vegetation, which may affect a large potion of the gene pond, those changes are clearly more visible and if so happens, individuals will have drastic mutations variants compared to their predecessors, and those will have more chances to survive.
For instance, we have a certain set of bugs which colors range brightly from light green to red, and a storm takes some over to an neighboring island, where birds doesn't see much of red, due lack of red fruits in the area.
Birds will prey on light-green, and yellow bugs, but not much on the orange-red ones. After some generations, the entire species of bug will not "become" red, but rather, the green and yellow phenotypes, or at least the active ones will be long gone, letting only the ones with red coloration. The gene pond will be always there, if by some manipulation of the environment, say by removing any predators, the green and yellow will slowly come back to existence, although in small numbers. Some times in cases like these, the separated group become a totally different species, let's say, if the birds are eating these bugs because they're shaped like peas, then the newer bugs beside red, will also be more elongated like grains of rice or peanuts so it doesn't fit well in the bird's beak.
There is a good reason why evolution is often misinterpreted this way, it is called Convergent Evolution, when two or more unrelated creatures converge into one similar design, see Dolphins - a mammal, and Sharks - a fish. This argument also lead many of sci-fi writers and scientists at the early 20th century to discredit H.G. Wells in his book The War of the Worlds, which presents advanced alien invaders as octopus-like creatures with beaks. Those scientists discredited any alien representation under the argument of convergent evolution, that any other alien advanced enough to develop a society should resemble the human body-plan, as that would be some sort of requirement for success as an species.
EVOLUTION IS LINEAR, THE "MARCH OF PROGRESS"
Well, is very common evolution to be depicted by the march of progress:
Probably the first thing that comes to mind when we think of evolution besides dinosaurs and Darwin.
To state a species come right after another like in a domino trail is by far the worst depiction of evolution, and again, it subjectively states evolution has a "goal" body-plan.
An evolution representation that better suits reality and still, very pretty spaced because we can't list every single path, but the significant ones where we able to distinguish with our eyes, it is called a Cladogram.
Where at the base we have the common ancestor of all the above species, each bifurcation is a common ancestor of the upcoming branches, like the first Theropod, that may have resembled a bit of a small velociraptor or coelophysis, but from there begun the branches to the dylophosaur, t-rex, and ultimately, birds.
Some animals been there since the beginning of time, like mammals, we just come to shine in the last 60 or so million years, but mammals and their ancestry been present since the Permian period, 270 million years ago, take as great example, the Dimetrodon, yes it is not a dinosaur, is one of the ancestors of mammals.
And lastly:
EVOLUTION CAN TAKE CRAZY PATHS
Yes, it can, but consistently. You can't have six-legged and four-legged creatures coexisting in the same planet for long, one will eventually outpass one another, all Earth animals (wayyyy general case for non-arthropod) are tetrapods, ie, decends the four-legged ancient salamander.
A head, two superior limbs, two inferior limbs, two eyes, two hearing apparatus and a tail, characteristics inherited from the first tetrapod.
As well, if your planet has been colonized by a hexapod, or octapod, all animals proceeding this common ancestor should have a similar body structure, just re-scaled or lost limbs/parts.
- M.O. Valent, 03/09/2019
