Debunking Shits About Evolution - Episode 10 [Darwinism - The Darwinian Model Of Evolution]

When the Neanderthals co-existed with the humans, there was a close resemblance with both, and that could explain why they didn't have much difficulty mating together. But you need to know this; as species evolve, the distinction between them becomes more pronounced, and the divergence becomes broader. Here's what I mean: Assuming the pure breed of Homo sapiens sapiens is represented with "X", and we represent a protégée of human+neanderthals as "Y", then we represent a human+denisovan crossbreed as "Z". A crossbreeding between Y and Z would further suppress the human genome in the subsequent generation, and crossbreeding them with the future generations of humans, you would notice that there would be obvious differences in the future subspecies of humans. That means; we are going to have diversity of the subspecies of the future humans. Are you scared?

You can get the full details here.

INTRODUCTION

In the last couple of years, the understanding of what humans evolved from has been getting clearer (thanks to the discovery of new and matching fossils to fit into the perceived evolutionary gaps) - well, except for some very few people that still believe that humans were created out of a very large milk drop _{just like the Fulanis' myth and legend}. And the truth is; as the day passes, more fossils are discovered, and the evolutionary tree becomes broader, while the gap becomes narrower. Just like we have considered; the humans in this extant form have survived mainly because of the breakthrough we had with evolution, and also our adaptation to be best fitted to our environment, but are all these exclusively related to the Darwinian model of evolution? In this myth-buster episode of evolution, we will be looking at some hidden facts about evolution. Length Alert: You guys have survived the length of my previous episodes, let's do it again. Join me as we evolve together in this episode.

DARWINISM AND PRO-DARWINISM

There has been a popular belief that the Charles Darwin's theory of evolution; "evolution by natural selection" is the basis of which the others hinge on - and no wonder the assertion under this has been "the survival of the best fitted". But looking at this holistically, did Darwin expressly mean the human aspect of evolution when he proposed that theory? Here's a little shocker for you: Charles Darwin proposed this theory in the book; Origin of Species that he published in the year 1859, but the fossils of one of the earliest discovered hominins; the Java man (also called Homo erectus erectus, which is one of the subspecies of the Homo erectus - The Upright Man) was discovered in 1891 _[ref]. That means; the earliest discovery of hominins post-dated the Darwinian theory of natural selection, so how do we think that Darwin was expressly referring to the human evolution when he proposed the theory? But then, looking at another of his book; "The Descent of Man", he expressly asserted that the modern human has an evolutionary descent from the ancient African Apes. How amazing, this assertion was made without laying hold on any fossils from any hominin specie whatsoever... Pretty interesting huh?

Looking at the Darwinian proposition, you would take note of a few things. Firstly, there's the Principle of Variation - This expressly states that various individuals within species would tend to exhibit variation, both in appearance and in adaptation from the others. Then putting this in apposition to the human evolution; this could infer that, in this present time (and maybe before now) there have been more than one species of hominins existing per time - in affirmation to a particular hypothesis known as "Multiregional Hypothesis".

_{Pictorial representation of multiregional hypothesis. From Wikimedia. Public Domain}

Wassup with Multiregional Hypothesis? I'll try to break this down for even the uninitiated to flow along. Multiregional hypothesis explains that there are evolutionally different species of humans existing from every regions of the earth, and these species evolved from entirely different species of hominins from each other. So by inference; African Australopithecines species evolved into the black folks (we; the Africans), then the Asians would be traceable to the Homo erectus pekinesis that was discovered in China. In the same way, the Java man (homo erectus erectus) found in java; Indonesia; must have been the ancestors of the present day people in the Australian region. But this does not put into consideration the fact that there is possibility of a crossbreed or interbreed between these species; like we saw in episode 9 - which showed some proofs of a crossbreed between Humans and the Neanderthals and Denisovas.

If the Multiregional hypothesis holds, then the fact that states that "all the extant modern humans came from the African descent" should be questionable. But from fossil evidences, you might need to know that the earliest of the hominin species; the Sahelanthropus; had an African descent, out of which the other sub-regional species emerged from. So remotely, the other sub-regional species had African evolutionary descent, and this has led to the establishment of the "Out of Africa Hypothesis", which looks more logical, based on the available fossil evidences. This hypothesis explains the fact that Africa is the host territory of the first hominins, out of which others migrated to other parts of the earth - just like we saw briefly in episode 9. And a vast majority of the strategic fossils in the evolution of humans has been discovered in Africa to point to the truism in this assertion _{I gave a list of some of them in the last episode, so I wouldn't bore us again with the list}.

INHERITANCE AND EVOLUTION

We have seen the Darwinian proposition in relation to the variation of species, now let's consider another proposition made by Darwin - and this is in the area of Inheritance. According to the Darwinian model, evolution hinges on traits which are passed across from the parent species to the protégée. And this is also in affirmation to the theory of "Inheritance of Acquired Traits" proposed by Jean Baptisté Lamarck, which expresses the fact that the traits and characteristics acquired throughout the lifetime of a specie can be passed across to the next generation, and this would go to the next generation, and on and on.

Our quadpedal relative, using their hands to support locomotion. From Flickr Licence:Public Domain

There are some facts to also prove the validity of this (even though there would always be perceived gaps in the trail of evolution, because none of us in this present time witnessed the evolutionary process... except you are 7million years old presently, lol). But drawing back to before the evolution of bipedalism (walking on two legs), guys were walking on all fours; but when necessity was laid on them, there was a shift to walking on just the two legs... thanks to the massive famine that hit the part of Africa they dwelled in, and the disappearance of trees to be hopping to and fro - so they needed another means to escape from predators, and boom!! bipedalism was initiated. This acquired trait was obviously passed on to the next generation, otherwise, the Sahelanthropus would have been the only specie to be bipedal, and they would have gone with their bipedalism, while the next species would still be quadpedal. Imagine if the extant modern humans are quadpedal, we would look so weird. Just like our relative on the right.

But much more than just inheriting acquired traits from the past generation, the next generation would also need to improve on the traits to be better; otherwise, it would not be called "evolution". For example, when the hands of our ancestral Ape-like species were freed from locomotion, they needed to do shit with their hands, and that led to the handling of tools. No wonder their hands became adapted for more opposable and firmer grip, as against their fathers that would only grab shits with their prehensile feet. This trait was also passed on to the next generation, and an improvement was also made.

When man began to handle and fashion tools (of which a breakthrough was seen in the Homo habilis - man with ability), the bipedalism of the next specie was consolidated upon. And instead of just walking on the two feet, they became erect; and that was how the Homo erectus (upright man) came to be. So you see, this is in affirmation of the theory of "Inheritance of Acquired Traits", also in apposition to the Darwinian principle of inheritance. All these happened behind the scene, and that was how we emerged as beautiful humans from some weird-looking Ape-like hominins. And the truth is; this process still continues - afterall, evolution is a series of adaptative changes (both behavioural, structural, and morphological) within the life of a specie, in response to alterations in their immediate environment; and this can be passed on to the next generation. This is what was revealed by the Darwinian model of human evolution.

FINAL WORDS

One of the patriarchs of the evolutionary science has remained Charles Darwin. But how amazing, some (if not all) of his propositions were done without laying hands on any fossil or transitional fossils of any hominin specie. Among his propositions are the principles of variation and inheritance. But in all these, it is worthy to note that evolution is a continuous process, and all these are necessary to ensure our survival - because that is one of the purposes of adaptation and evolution.

Thanks for reading evolving