If the geological history of the earth was different ...?

Question

If the geological history of the earth was different from how it is, i.e. we never had Pangea; more sea/less land, different geological set-up ;or any other combinations would life, as we know it today be recognisable to us as humans? Would humans even exist? Say, for argument that all the major extinctions occurred at the same point in time etc.

thankyou

Answer 1

Sure, continental drift played some role in the evolution of species (such as Madagascar or New Zealand having distinct life forms that are different from elsewhere) but overall nature has reproduced the same elements over and over again. Flight has developed in different life forms (dinosaurs and birds most noteably, but also gliding in amphibians, reptiles and mammals). Each trait, like flying, appears to find it's way into different forms of life as that life form tries to gain an evolutionary niche over it's counterparts.

People have theorized that life forming elsewhere will take on similar development because there are only so many ways to receive environmental information (the senses) as well as mobility (swim, crawl, walk, fly) and energy (eating, photosythesis, breathing). Different environments might allow life forms to certainly have abilities we don't have on Earth, but over all, they'll need to develop mechanisms that essentially do what has happened on Earth for anything more advanced than the most basic bacteria.

As far as extinctions...they've caused nearly 90% of extinction on the planet, with three mass extinctions. Each of those provided an opportunity for the remaining life to have a new environment to compete. Had they not occured, it might sound crazy, but the Velicoraptor type species might have become even more intelligent (they are already thought to have behaved like pack animals) and had limbs that probably could have further developed to be more capable, such as ours.

Nice question. Thanks for asking.

Answer 2

I think life would change significantly. I would assume it would be like the butterfly effect. Any little change could effect the way life has developed. One aspect that comes to mind is the country of Madagascar. Lemurs exist only on the island of Madagascar because it is cut off from the rest of the world. Lemurs have no natural predators so their populations thrives, however, if they were connected to Africa, predators would have destroyed their population just as they have on the mainland. Humans may have had similar advantages in their development throughout history.
One major idea is that primates were able to survive and thrive after the extinctions of the dinosaurs and other great predators. With the great predators destroyed, Primates were able to leave the trees and develop more to living on the ground. They now had an advantage by being able to live in the trees and come out of the trees for new food sources.

Answer 3

Our physical aspect might be different, but what is important is that we are different from anything else, different from the animal, the vegetable and the mineral, in that we are personal beings.

If our conscious awareness arose from unconscious sources (matter, energy, time and chance) then consciousness equates to unconsciousness; that is to say, consciousness is illusory and meaningless, so that it would not matter whether we were different or not.

If personal beings, ourselves, exist, this strongly suggests that the things which did not cause our conscious awareness (matter, energy, time and chance) did not play a significant role, regardless of our outward shape or appearance.

Answer 4

Read "Wonderful Life" by Steven J. Gould. The upshot is that if we rewound time back to the Cambrian explosion and started over, life would probably not look anything like it does now. Humans or some other intelligent species may or may not have evolved.