THE BIOGRAPHY OF THE UNIVERSE - The Evolution of Man (Part 6) THE END

in #steemstem6 years ago (edited)

The_evolution_of_man-_a_popular_exposition_of_the_principal_points_of_human_ontogeny_and_phylogene_(1896)_(14594999469).jpg
Image Source: Wikimedia commons

Taking account of our biological ancestors, this article intends to show the evolutionary processes that lead to the rise of the Homo-sapiens (MAN). A complete and honest scientific analysis of we humans suggests that we are more or less living members and descendants of different life forms that existed a long time ago. Like the bird that can sing, and the fish that can dive, we are the animals that can reason; a species that walks upright, form social groups and evolved from the forests of Africa about three hundred thousand years ago.

Biologists and geologists insist that we are descendants of a family of animals called Hominini. Hominini is a group in the taxonomic rank that includes Ape-like relatives such as Humans, Gorillas, Chimpanzees, Neanderthals, Dryopithecus and other extinct relatives.

WHAT CHANGED?

To account for the biological changes in the animals, we look at their morphological change, which is the scientific study of the form and structure of animals, usually without regard to function - Physiological Change.

The arm of biology that is concerned with the activities and functions of living material (like cells, tissues and organs) and of the chemical and physical processes involved, and well as the behavioural changes which deal with the reaction of animals to situations and events that occur in their environment.

Achievable mainly through scientific query that seeks to understand the biochemical, physical, and mechanical functions of man, its organs and cells of which they are made up of.

The Taxonomic Rank

The word 'Taxonomy' was derived from two Greek words 'Arrangement' and 'Method'. It is a well-defined distribution of biological life forms with respect to their distinguishing features.

It is the application and science of classifying concepts or things and also includes the principles that underlie such classification.

When similar organisms are grouped they combine to form 'Texa' (Taxon - singular).

Being Bipedal

The word Bipedal simply means "able to stand or move on two feet". This is one very obvious modification in human beings and biologists argue that this feature is largely responsible for the unique skeletal structure of all hominids (the Ape-like Hominin family) that walk on two legs. It is still a controversy as to which of our primitive ancestors started this bipedal movement, however, biologists have narrowed the search down to two hominids (Sahelanthropus and Orrorin) that lived about 6.5 million years ago.

The other animals that walked on all fours, the chimpanzee and gorilla, also left the ancestral chain about 6.5 billion years ago, this implies that either Orrorin or Sahelanthropus is likely our last mutual ancestor with the chimpanzee and gorilla. Ardipithecus, the first completely Bipedal animal came later.

These bipeds will later evolve to become Australopithecines (another ape-like animal in the Hominin family) and much later join the genus: Homo. Biologists suspect that the reason our primitive ancestors adapted this two-leg movement is because it allowed the hands of the animals to do other things like, pick up food, use less energy when moving and still cover more grounds, allow for the carrying of tools while hunting and fighting, increase the animal's line of sight etc. When animals walk on all fours, they tend to absorb more sunlight which may cause biological harm, the bipedal movement allowed the animal to stand upright, reducing the total surface area bare to the sun. It allowed their legs to elongate and their arms reduce in length because there was no need anymore to swing on the trees. Studies show that Australopithecines were known for having large feet which helped them hang unto trees, this feature was also lost for lack of use during the generation of the Homo-Habilis.

The conversion from knuckle-walking to bipedalism did not just contribute changes to the structure of the feet and arms, it covered a wide range of skeletal formation including the Vertebral column, Pelvis, ankles, and skull. The femur, which is the bone that extends from the pelvis to the knee, changed its shape in such a way that allows the centre of gravity rest in the centre of the body. The knee and joints between bones became stronger because they had to hold more weight. The vertebral column was gradually transformed to a long 'S' shaped object which aided the hold of individual vertebrae bones keeping an upright position against the pull of gravity making the lumbar vertebrae shorter and wider. All five toes in each leg changed their direction to facing front as this aided the animal to thrust forward and sprint when running.

BIRTH

The transition to bipedal movement caused a significant change in the mechanism of sexual reproduction, this is most-likely because walking straight with two legs meant that the size of the pelvis and birth canal be reduced. This is why the birth processes of humans is difficult compared to that of their primitive ancestors. Due to this reduction, when a female is about to give birth to a child, the head of the fetus must be directed opposite its mother's head as it enters the birth canal which then turns it perpendicularly as it leaves the canal. This reduction also affected the size of the fetus' skull making its brain smaller and allowing easy passage into the physical world. All these changes caused children to come out from the womb prematurely, making human babies unable to walk or do anything useful for almost twelve months after their birth. Other primates mature relatively earlier.

This may not have been efficient for the human species because surviving in the forest where there are wild animals meant all hands on deck, as soon as possible. Because children were born prematurely, they had to depend on their parents for a much longer time. This led to the issue of delay in sexual maturity in humans which in turn also led to the evolution of menopause in women. Today, psychologists say that this explains why older women (grandmothers) are best at taking care of younger children (grand-daughters) than their own children.

THE BIG HEAD

To compare the brain of our primitive ancestors with ours, one will be greeted with the fact that the human brain is unique. As evolutionary time passed, the size of the brain developed, its faculties like memory and speed greatly surpasses any animal in the hominin family. Evidence suggests that the human brain should be about three times larger than those of chimps and generally about 1,330 cm3 in size.

In the long past, the bipedal movement of animals like Australopithecus anamensis and Ardipithecus resulted to smaller brain-size. Brain changes in size were left almost completely unattended by nature for many generations, however, changes started to occur during the rise of their future species: the Homo Habilis which had a brain-size (just somewhat higher than that of chimps) of about 600 cm3. Then came a new species: Homo Erectus, having the brain-size of about 800 to 1,100 cm3. Neanderthals also arose later from this group and had a brain size of about 1,200—1,900 cm3 which is considerably bigger than that of Homo-sapiens(1,330 cm3). The upgrade in the brain of the Homo-sapiens emerged after the birth of the organism and completely depended on the activities of the organism for development and has been that way for 2 million years.

In the human brain, one of the four major divisions of the cerebrum - the temporal lobe, which is responsible for the articulation of language - developed so well that humans could now use language as a representation of thought, i.e. they could now talk as fast as they could think and they could also learn different languages. Changes also occurred in the prefrontal cortex - the anterior part of the frontal lobes of the brain that handles the task of making decisions - which led to the rise of a more complex social ecosystem.

Beef Consumption

Studies show that the application of meat into their diet greatly accelerated the growth of the brain. Unlike other animals that ate meat, our primitive ancestors had no claws or sharp long tooths to catch their preys, the best tool given to them by nature for their survival were their brains, so they needed to work really hard for food like meat. They had to learn how to hunt - mostly by trial and error - and how to set traps. They learnt how to cut the meat into bits and share evenly with the group so as to prevent any dis-organization because they needed each other for hunting.

799px-PRIMITIVE_MAN_HUNTING_ANIMALS_at_the_Museum_of_Vietnamese_History.JPG
Image by HappyMidnight - Wikimedia Commons (CC BY-SA 3.0)

Our ancestors had bigger and harder stomachs which aided their body to break-down uncooked food. However, this was very less efficient because they did not possess good-enough teeth or patience to chew raw meat properly. Later they discovered fire which they used for different things including cooking. Cooking food especially meat, made it possible for them to get more nutrients from their meals and use less energy in digestion. This allowed for the reduction in the size of their stomach and increased their brain-size over time.

The socialization of early humans in groups also played a major role in increasing their intelligence because they had to exhibit actions - solving important problems that arose which became more complex as the members of their group increased. They had to maintain peace and co-operation, therefore, they needed communication within themselves hence - language.

Moving on to the more obvious changes in humans through evolution. The human brain placed more importance on sight instead of smell. They evolved smaller intestines, lost a lot of hair, developed tiny sweat glands, and evolved the chin - which is possessed only by human beings.

Humans have continued to grow in knowledge, following the simple law of life which is to survive and reproduce. We are doing more or less the same things their ancestors did, using our brains - the special gift from a selfish universe that needed to know itself.

References

WIKIPEDIA | Human Evolution

ALL ABOUT SCIENCE | Evolution of Man

BRITANNICA | Human Evolution

HOW STUFF WORK | Evolution

TELEGRAPH | Evolution of Man

SCIENCING | Seven Stages of Early Man

Sort:  

Your post has been personally reviewed and was considered to be a well written article.
You received a 60.0% upvote since you are a member of geopolis and wrote in the category of "geology".

To read more about us and what we do, click here.
https://steemit.com/geopolis/@geopolis/geopolis-the-community-for-global-sciences-update-4

I guess those texts in blocked quotes dont belong to you? what about their sources?

They are all mine, I was just trying to highlight some key points. I will remove the block quotes as soon as I get on my laptop @stemng

Coin Marketplace

STEEM 0.35
TRX 0.12
JST 0.040
BTC 70351.33
ETH 3563.43
USDT 1.00
SBD 4.72