//://////////////////////////////////////////// Darwin hypothesized a Missing Link Species between humans and chimpanzees . The Missing link is in the middle link ; its bi-pedal like humans , but small brained like chimps.
Charles Brown “Early primates began to emerge 65 million years ago during the time of cooling global temperatures to an extent as to cause the extinction of dinosaurs and many other species as well. It has been suggested a meteor or some other sort of extraterrestria entity slamming into the earth where the Yucatán peninsula of Mexico now exist set the climate change in motion. For 100 million years dinosaurs that dominated most terrestrial environments suitable for vertebrates and they would probably have continued to do so if the earth had not cooled . Although mammals appeared at about the same time as reptiles, they existed only as small nocturnal animals. The demise of dinosaurs opened up new opportunities, allowing mammals to begin their great adaptive radiation into a variety of species including our own ancestors the early primates.
This is a Family Tree of Life symbolic representation of the Primate order of the Mammal class of animals
. By 60 million years ago primates inhabit in North America and Eurasia. By 40 million years ago, diurnal anthropoid primates appeared. By about 23 million years ago at the start of the geologic epoch known as the Miocene, the first fossil apes , or hominoids, begin to appear in Asia Africa and Europe.
Hominoids are the broad shouldered tail is prime is an includes all living an extinct apes and humans. The word hominoid comes from the Latin root homo and harmony meaning human being and the suffix Lloyds meaning resembling. Remains of age from the miles in have been found from the chaos of China, to the force of France, to eastern Africa, where the earliest fossils of bipeds have been found. Climatic changes it into motion during the miles in impact the success of the human line once it originated. In particular, the uplifting and drawing of the eastern third of Africa a process known as rifting open new ecological niches for our ancestors.
Here is a Family Tree of Life representation of the Hominoids . We humans are hominoids.
HUMAN EVOLUTION Genetic and bio chemical studies have confirm that the African apes – chimpanzees, Bonobo’s, and gorillas – are our closest living relatives in the animal kingdom.By comparing genes and proteins among living apes scientists estimate that at sometime between five and 8 million years ago, humans chimpanzees and gorillas began to follow separate evolutionary courses.
Bipedalism is a special form of loco motion on 2 feet makes humans and their ancestors distinct among the hominoids. Although we might like to think that.
The first bi-peds or habitually bipedal primate or HOMININS
BETWEEN five and 15 million years ago various kinds of HOMINOIDS lived throughout Africa and Asia; one of these apes living in Africa between five and 8 million years ago was a direct ancestor to the human line.
The discovery of Orrorin ORRORIN fossils l meaning the original man bars in Canyon 2001 may be this ancestor I discovered and Chad central Africa has it been since suggested as the original Human Ancestor. Also Ardiperhicus 4.4 million years ago approximately may be that ancestor.
The anatomy of bipedalism
Classifying a hominoid fossils definitively as part of the human evolutionary line requires evidence of bipedalism. Anatomical changes literally from head to toe accompany this human form of locomotion. The skull preserved evidence of walking on 2 feet because balancing it above the spinal column in an upright posture requires a relatively centered position above the spinal column. S The spinal cord leaves the skulll at its base through an opening called the foramen magnum Latin for big opening. In the knuckle walkers like chimps the foramen magnum sets toward the back of the skull; whereas it has a more forward a position in habitually bipedal primate or bi-peds .
In BIPEDS the spinal column makes a series of convex and concave curves that together maintain the body in an upright posture by positioning the body’s center of gravity in the above the legs rather than forward . The curves correspond to the neck ( cervical), chest thoracic), lower back ( lumbar), and pelvic ( sacral) regions of the spine respectively. In champs the shape of the spine forms a single arching curve ( see )
Pelvic shapes also distinguish BI-Peds from other apes . instead of an elongated pelvis following of the arc of the spine as in chimps, Bi-peds have wider foreshorten pelvises . it provides structural for support for the upright body . With a wide pelvis , a biped’s lower limbs would be oriented away from the body center of gravity if the thigh bones did not angle toward each other from the hip to the knee, phenomenon described as “kneeing in“. Notice how your knees and feet in touch when standing while your hip joint remain widely spaced .
“An asymmetrical knee joint allows the side bones and vertically oriented shin bones to meet despite their different orientations. The bipedal foot has stable arches and no opposable big toe. In general humans and their ancestors possess shorter toes than the other apes
. These anatomical features allow Paleo anthropologists to diagnose bipedal locomotion even from fragmentary remains such as the top of a shin bone or the base of a skull. Fossilized footprints can also establish bipedal locomotion, by preserving the characteristic stride, which in while shifting the body weight from one foot to the other as a non-supporting foot swings forward. The most dramatic confirmation of walking ability in early human ancestors come from Laetoli in Tanzania in East Africa Winans ancient biped walked across newly fallen volcanic ash 3.6 million years ago.
In the ancient savannas open grassland with scattered trees and grows bipedalism has advantages. Although bipeds could not run as fast as quadrupeds, they could keep a steady pace over long distances in search of food and water without tiring. With free hands, bipeds could take food where it could be eaten in relative safety, could carry infants rather than it relying on the babies to hang on for themselves. Bipeds could use their hands to wield sticks or other objects to fight off predators or kill prey. Other ape can do this but only for a short bursts of time and weaker. Erect posture also supports endurance running as it prevents overheating by exposing a smaller area of the body to the direct heat of the sun. Furthermore bipods with their head held high could see farther spotting food as well as predators from a distance.
Australopithecines Between four and 5 million years ago the environment of Eastern and Southern Africa was a mosaic of open country with pockets of Woodland. Although ARDIPETHICUS inhabited some of the Woodland pockets later human ancestors inhabited the savannah , and researchers assign them to one or another species of the genus AUSTRALOPITHECINE from the Latin AUST meaning southern and the Greek PITHECUS meaning ape. Scholars Although fully adapted to bipedalism, Australopithecus’s curved toe bones and also relativelt long arms that they had not given up tree climbing altogether. Like chimps they may have built night nests in the trees as refuge from dangerous African savanna predators.
Bipedal stance could help pick seeds nuts and fruits in trees a technique orangutans employ today.
In summary of what is said above and more
what is the basic outline of mammalian primate evolution and related geological events?
One. The first mammals appeared over 200 million years ago and were small nocturnal creatures. Since that time the positions of the Earth land masses have changed dramatically.
Two. The mass extinction of the dinosaurs about 65 million years ago allowed for an adaptive radiation of mammals and ultimately included the origins of the primates.
Three. Old World the New World primate species separated by about 40 million years , and hominoids, the broad shouldered , tailess primates , includes all living an extinct apes and humans, began to appear about 23 million years ago throughout Asia Africa and Europe. genetics studies today have confirmed that the African chimpanzees and gorillas are our closest living relative species , closest “cousins “ on the Family Tree of Life .
Next what is the anatomy of bipedalism how do we recognize of human line in the fossil record ?
1) larger brains ( and longer childhoods) is the most striking difference between humans and our closest primate relatives ; larger brains are much more than bipedal locomotion , though bipedalism preceded brain expansion by several million years and appeared sometime between five and 6 million years ago.
2) skeletal changes from the skull down to the toes a company bipedalism. Next how do we difference there a
How do we differentiate the earliest bipeds from one another?
1) the forest dwelling Ardipithecus seems to be the earliest definite BI-PED
2) Australopithecus came next and then included two basic types of Robust vegetarian Australopithecine , a line that went extinct And the gracile Australopithecus that evolved into the genus homo ( humans)
3) the increase in brain size did not appear in human evolution evolutionary history until much later with the appearance of Homo habilis about 2.5 million years ago and that beginning of increase in brain size is the origin of human beings because bigger brains per body size -and culture and language which we can only have with big brains -are what differentiate us from all other animals.
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