Human Evolution GifThe story of humanity is something every one of us can learn from, as well as add to, if we’re patient enough to embrace the details. Analyzing the details and complexities of the human story is something mostly done by scientists (paleoanthropologists) today, but I believe it shouldn’t just be limited to scientists. Thankfully we live in a society where the public can access libraries and even buy subscriptions to online scholarly databases like JSTOR and EBSCO (in high school we called this Ebscohost) that allow us to have access to this pertinent information at our fingertips. Information that can blow your mind or even change your life.

We have overcome some long odds and harsh conditions on the ancient African savanna to get to a taxing 7.5 billion global population. A population that is growing faster and faster. Some predict it will be around 9.7 billion by 2050. Interestingly, at the center of this rapidly growing population is Africa, the continent with the fastest growing population on Earth. Yet Africa is the same place human lineages have had to adapt and struggle to survive so many millions of years ago.

What the Dinosaurs Left Behind

After the KT extinction event that obliterated the dinosaurs, primate-like mammals began to appear on the scene. These early primates during this time inhabited the warm climates of Asia, Europe, North Africa, and Western North America¹. These small insect-eating animals eventually evolved to become prosimians. When you think of a prosimian think of a lemur. I especially remember the lemur from Zoboomafoo who had always made my childhood a little brighter. Prosimians also include animals such as tarsiers, aye-ayes, and bush babies.

During the Eocene Epoch (55.8-33.9 mya or million years ago) the prosimians gradually developed bigger bodies and brains as time went on eventually leading to the old and new world monkeys as well as apes. They were next evolutionary step.

Tetonius Homunculus
Artist rendering of an Eocene prosimian, T. Homunculus.

As monkeys came onto the scene and primates developed increasingly vertical postures, stereoscopic vision and bigger brains, competition, along with climate changes, thinned out the herd. There were many more prosimians that have existed than what we know of today. One of them includes my friend to the right. The prosimian population was nearly four times greater until a global warming event that prompted rapid evolution hit many species pretty hard.

Unfortunately, the fossil record is spotty and hard to acutely decipher. This is why there is so much disagreement within the discipline of paleoanthropology. We don’t have all the evidence at our fingertips to answer all the questions we have regarding the past. It’s something we need to continue to work towards as time goes on; but based on what we do know our ancestry is special.

Leaving the Comfort Zone

It’s fascinating to look at the creatures we once were. We came from small rodent-like animals to being medium-sized hyper intelligent creatures who can invent artificial organs. But we’re not the only ones who have gone on to evolve in such unexpected ways: the ancestors of whales were hooved and walked on land quite like hippos, and, of course, birds evolved from dinosaurs. It’s amazing how unpredictable evolution can be.

African SavannaNow let’s fast forward to the divergence of chimpanzees and us. Sahelanthropus Tchadensis (discovered in Chad in 2001) was an upright walking ape that heavily resembled today’s bonobos³. He was one of the ancient humans, along with Kenyathropus and Ardipethicus. Not much is known about this seven million year old human ancestor, but scientists understand it lived in the western-central region of Africa and had a diet consisting mainly of plants. However, as the landscape started to change and evolutionary paths diverged many hominids found themselves living on the African savanna where they had to adopt new strategies for survival opposed to the ones used in the jungles.

As time went on more human lineages began to emerge. There were the robust humans which included the Paranthropuses and there were the gracile humans which included most other species. For example, Paranthropus Boisei was a man with a huge sagittal crest and powerful jaws that had a mostly plant based diet. Some might refer to him as Nutcracker Man. On the other hand, there were more gracile humans like Homo Erectus who ate meat, which in turn led to a less complex digestive tract and more resources to give to the ever so demanding brain. It was the carnivorous diets of our ancestors that contributed, in part, to our enlarged brains. With large brains came less facial prognathism, more resources for hunting prey, and more complex humans. Meanwhile our robust cousins were suffering because of how insufficient their diets were relative to the energy they needed to survive. This is why they did not last. Gracile humans had to leave their comfort zones and develop new ways of surviving and even reproducing in order to last to the next generations.

Forever Young

Our ancestors had to develop new ways in order to survive on the harsh environment that is the African savanna. One particular way in which we survived in conjunction with our improving bipedal ability was giving birth sooner. Early humans that gave birth sooner were more likely to survive the birth (first of all) and there were also a variety of other benefits as well.

We humans are generally born helpless and relatively early compared to some other species. We take decades to mature into adults when parts of our bodies stop growing. Other animals don’t really do this. This is referred to as neoteny. With smaller hips due to bipedalism and innovations in the birth process we were able to survive. One of the benefits of neoteny included further innovations in brain development.

Humans are born with very large brains compared to other apes. We also don’t stop developing our brains completely until we’re in our 20s while monkeys, for example, arrive at birth with 70% of their cerebral development, with the next 30% being created within the next six months². Our unmatched brain power has been described by some as extraordinarily strange and unique in nature.

The Power of Man

Humans undoubtedly rule the world. We create and innovate things that have never been done before on a daily basis that raise the quality of life for most living things. We can be found in so many different environments all around the world. We also out competed previous hominini tribesmen to be able to thrive the way that we do. But that doesn’t mean we’ve never had our moments of uncertainty, or possible extinction. The turbulent climatic shifts of the last ice age was a test we almost failed, but we endured and made it through to eventually become what we are today.

To be continued, next week on The Fire

-Isaiah Dix

Sources:

  1. http://anthro.palomar.edu/earlyprimates/early_2.htm
  2. Last Ape Standing by Chip Walter
  3. humanorigins.si.edu
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About the Author Isaiah Dix

Hi. I'm a millennial blogger who loves living things large and small, people of all shades, and the world at large.

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