### <div class=phishy>Introduction</div> 

Evolution; like we may have been aware of; is the series of adaptative features within a specie that have been passed on from one generation to another generation. Human in this extant form - the Homo sapiens sapiens, has witnessed evolutionary progression from the earliest hominid species down the line. And in this process of evolution, some features would have been acquired, while some would have been dropped. Here, we will be looking at what has changed in us as we evolved (the past, present, and future of human evolution).

https://i.imgur.com/it8fjRG.jpg

<sub>[Image Source: [Pixabay](https://pixabay.com/en/evolution-evolving-mankind-men-ape-1295256/). CC0 Licensed]</sub>

You would agree with me that the concept of evolution has been; of all the science sub-disciplines; heavily theorized. The reasons being that the extant humans didn't live to witness all these evolutionary processes first-hand, but we have pointers to put us in the right direction - thanks to archeology, paleontology, and palaeoanthropology. And from some of the fossils discovered, we can infer; to a considerably fair extent; the nature, features, and adaptation of the hominid species that have lived before us. It is also worthy to note that the process of evolution is progressive - that is, it is a continuous process that has been happening for billions of years; since the formation of the first life form.

However, we will be focusing on just the trail of humans evolution. Though the process of evolution has been inferred to be a slow process (judging from the [theory of gradualism](https://en.m.wikipedia.org/wiki/Gradualism)), but over the last couple of years, the speed has tend to increase by a large margin <sub>[[ref](https://singularityhub.com/2016/03/22/technology-feels-like-its-accelerating-because-it-actually-is/)]</sub> - maybe this could be a pointer to the concept of catastrophism (or maybe we should blame technology for that). So what evidences are there to prove that we are actually evolving? After all, evolution has to do with adaptation - and adaptation is substantiated with visible evidences. Okay, we'll be looking at the things that have changed in us to prove that we; indeed; are evolving.

### <div class=phishy>Our Feet</div> 

Have you taken time to look at the feet of the present day Apes, Gorillas, and all whatnot? You would agree with me that their feet are prehensile, which enable them to grasp things with their feet, but the human feet is somewhat different. Before I continue, I would love to point out that `the present day humans didn't evolve from the present day ape, but both of them shared a common ancestry`. Coming to the area of the feet; why are our feet not prehensile?

Taking a little journey back to one of the earliest hominid species that marked a borderline between Apes and Man - the Australopithecus, which had a combo of prehensile and arched feet <sub>[[ref](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1571304/)]</sub>, which; of course; are both features of man and ape. But going further before the Australopithecus, a particular specie; the Sahelanthropus - which was very primitive and had some obvious ape features which included the prehensile feet <sub>[[ref](https://en.m.wikipedia.org/wiki/Sahelanthropus)]</sub>. What does this suggest to you? Very simple: they were more arboreal (tree-dwellers) than the Australopithecus, and their feet enabled them to grasp the branches of trees.

https://i.imgur.com/aW4Tgke.jpg

<sub>[Image Source: [Flickr](https://www.flickr.com/photos/internetarchivebookimages/14596997679/). Author: Tylor, Edward Burnett 1832-1917. Public Domain Licensed]</sub>

But as the species evolved, there was lesser emphasis laid on the need to climb trees, and they gradually shifted to walking on the ground. And as you know, Lamarck’s theory of "Use and Disuse" would come into play - `which establishes the fact that organisms would lose the features they don't use often or require, while consolidating on the ones that are needed`. And as they continued to shift to land-dwelling, they started losing their opposable digits and the prehensile feet evolved to a little flatter feet. And ultimately, there was a paradigm shift to bipedalism (walking on just the two feet, without the need to use your hands for support) - and at this point, man would have been said to be fully land-dwelling.

Though bipedalism didn't necessarily indicate uprightness. I mean; they could be waking on two feet but with an arched back. But a breakthrough was achieved in the Homo erectus (Pithecanthropus erectus) which was the point at which man was said to be upright <sub>[[ref](http://humanorigins.si.edu/evidence/human-fossils/species/homo-erectus)]</sub> - no wonder the "erectus" sufficed the name (which means upright man). That is why humans in this extant form have a much adapted feet for locomotion on the ground than our ancestral ape-like grandpas. Okay let's look at another thing that changed.

### <div class=phishy>Our Hair</div> 

Why were our ancestors much hairy than us? Like the Sahelanthropus I mentioned earlier; which was almost covered in hair (or I should say; fur) - of course, that was an obvious ape feature. But observably; through the study of their fossils; these species were seen to lose hair down the line until it came to the extant modern humans (I wonder how we would have looked like with fur).

https://i.imgur.com/xK8OmkL.jpg

<sub>[Sahelanthropus. Source: [Wikimedia Commons](https://commons.wikimedia.org/wiki/File:Sahe_tchadensis.jpg). Author: TheCarlagas. [CC BY-SA 3.0](https://creativecommons.org/licenses/by-sa/3.0/deed.en) licensed]</sub>

Though many factors are responsible for the loss of hair, but temperature has been remotely queried. During the ice age, how do you think the ancestral hominid species were able to survive the brutal cold without winter jacket and all whatnot? Well, they had thick furs to act as insulators and trapped in heat to keep themselves warm, which prevented them from freezing. But as the years go by, the temperature of the earth adds up a little fraction <sub>[[ref](https://www.c2es.org/2017/03/its-certain-the-earth-is-getting-warmer-and-human-activity-is-largely-to-blame/)]</sub>, and also, coupled with the fact that the idea of clothing came to be, there wasn't much reliance on the need to use fur as a protection against extreme cold. So the species had to lose the dense mass of hair to compensate for the hotter environment.

Going by this trend, we may even lose more hair and our future generations could be more bald than we are - I mean, why do we need much hair when we can lay our hands on winter jacket for the cold? Also, technology has a part to play in this - our homes are fitted with heaters; do we still need the natural insulative properties provided by the thick fur? After all, being less hairy makes us look beautiful, except you, yes you.

### <div class=phishy>Brain mass</div> 

The brain mass of the earlier hominid species; as evidenced in the study of their skulls and inter-cranial curvatures; were much lower than the brain of the humans in this present day. But as it were, as they evolved, it was observed that they made use of tools (which started off from very crude stone tools). A major breakthrough in this was the [Homo habilis](http://humanorigins.si.edu/evidence/human-fossils/species/homo-habilis) (which was interpreted as the man with ability) - because of the tools they made use of. And this was a direct function of their brain size; which also is shown in their mental prowess.

https://i.imgur.com/eDaeeym.jpg 

<sub>[Brain and skull size of primates. Source: [Wikimedia](https://commons.wikimedia.org/wiki/File:Primate_skull_series_with_legend.png). Author: Christopher Walsh. [CC BY-SA 2.5](https://creativecommons.org/licenses/by-sa/2.5/deed.en) Licensed]</sub>

Take for example; the Australopithecus had about 1/2 the brain size of the extant modern man, and they majorly made use of objects that they found as tools <sub>[[ref](http://humanorigins.si.edu/evidence/human-fossils/species/australopithecus-afarensis)]</sub> - but they weren't known to completely fashion their own tools. But the subsequent specie; the Pithecanthropus erectus; which had much bigger brain size, created their own crude stone tools <sub>[[ref](http://humanorigins.si.edu/evidence/human-fossils/species/homo-erectus)]<sub>. What does this tell you? The brain power and intelligence of the ancestral grandpas of modern man was a function of their brain size. And no doubt, the evolution in brain size has caused humans to pick up awesome creative acumen. No wonder we have seen scientific and technological marvels in this era.

All these; and more; are what have made humans uniquely different from apes and ape-men. But notwithstanding, there are still some inherent similarities in the both creatures. But like you know; "evolution" is still evolving, and man keeps picking up entirely new adaptative features and traits.

### <div class=phishy>Conclusion</div> 

Humans in this extant form have been inferred to have evolved over the years from some bizarre-looking hominid species. But obviously, we have picked up some features that made us somewhat different from them. We have seen these features in this post (but on a lighter mood; if any of these human-features is lacking in you, don't feel bad, you're just a resemblance of the ape-like ancestors you evolved from, lol)

***Thanks for reading***

> References for further reading

- [Feet and bipedalism of ancient species](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1571304/)
- [Nature.com/earliest hominid species](https://www.nature.com/scitable/knowledge/library/the-earliest-hominins-sahelanthropus-orrorin-and-ardipithecus-67648286)
- [Uprightness and bipdelism in homo erectus](http://humanorigins.si.edu/evidence/human-fossils/species/homo-erectus)
- [Loss of hair as we evolved](https://www.independent.co.uk/news/science/why-humans-lost-their-body-hair-to-stop-their-brains-from-overheating-as-we-evolved-8498623.html)
- [Humans - the hairless primate](https://www.scientificamerican.com/article/latest-theory-human-body-hair/)
- [Human brain evolution](http://humanorigins.si.edu/human-characteristics/brains)

> All Images are CC licensed and are linked to their sources

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