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Human Evolution - Coggle Diagram
Human Evolution
Last Common Ancestor Evidence from fossils, genetic studies, and proteins indicate that humans and chimpanzees had a common ancestor millions of years ago. Most scientists believe that the human family tree diverged from chimpanzees and other apes seven million years ago. Until recently, it was thought that the common ancestor looked like a chimpanzee, with features such as a short back, arms, and hands adapted to grasping, swinging branches, and wrists and forearms meant for knuckle-walking (Blaxland, 2018).
In 2014 a skull was found in Kenya in the Napudet area. It was named Alesi since it means ancestor. Alesi shows exactly what the ancestor of all modern apes and humans looked like. The Lemon sized skull had baby teeth present, which were used to determine the age by using the enamel rings (similar to the rings on a tree). The teeth revealed that Alesi was 16 months old. She belonged to the genus, or group of species, known as Nyanzapithecus, a sister group to the hominoids discovered about 30 years ago. However, Alesi's teeth were much larger, implying that they belonged to Nyanzipithecus alesi. These species existed in Africa 10 million years ago and were close to the origin of apes and humans and originated in Africa. The skull looked like a baby gibbon since it's a close relative to living apes. The specimen could give us ideas of what the common ancestor might have looked like, and since the specimen looks like a gibbon, it would support the idea that the common ancestor of all apes and humans looked like a gibbon(Choi, 2017). 
Sahelanthropus tchadensis It is one of the oldest known species in the human family tree. This species lived sometime between 7 and 6 million years ago in West-Central Africa (Chad).Upright walking based on the foramen magnum (the large opening where the spinal cord exits out of the cranium from the brain) is located further forward (on the underside of the cranium) than in apes or any other primate except humans. This feature indicates that the head of Sahelanthropus was held on an upright body, probably associated with walking on two legs. Ape-like features included:Small brain (even smaller than chimpanzee’s)
Sloping face
Prominent brow ridges
Elongated skull Human like features included:
Small canon teeth
Short middle part of the face
The spinal cord opens underneath the skull instead of towards the back, as seen in non-bipedal apes.
Orrorin tugenensisLiving around 6 million years ago,Approximately the size of a chimpanzee
Had small teeth with thick enamel, similar to modern humans. From Orrorin's low, rounded molars and small canine teeth, paleoanthropologists can infer that this species ate mainly a plant-based diet. This probably included leaves, fruit, seeds, roots, nuts, and insects. The most important fossil of this species is an upper femur, showing evidence of bone buildup typical of a biped -
Orrorin tugenensis individuals climbed trees but also probably walked upright with two legs on the ground.
Ardipithecus ramidus
4.4 million years ago Eastern Africa (Middle Awash and Gona, Ethiopia)The foot indicates a divergent large toe combined with a rigid foot concerning bipedal behavior.
The pelvis, shows adaptations that combine tree-climbing and bipedal activity.
A good sample of canine teeth of this species indicates very little difference in size between males and females in this species.
Australopithecus afarensis
3.85 to 2.95 million years agoEastern Africa (Ethiopia, Kenya, Tanzania)Australopithecus afarensis is one of the longest-lived and best-known early human species
This species survived for more than 900,000 years, which is over four times as long as our own species has been around. Au. afarensis had apelike face proportions (a flat nose, a strongly projecting lower jaw) and braincase (with a small brain, usually less than 500 cubic centimeters -- about 1/3 the size of a modern human brain), and long, strong arms with curved fingers adapted for climbing trees.
They also had small canine teeth like all other early humans and a body that stood on two legs and regularly walked upright.
Australopithecus africanus
3.3 to 2.1 million years ago
South AfricaAu. africanus combination of human-like and ape-like features. Compared to Au. afarensis,
Au. africanus had a rounder cranium housing a larger brain and smaller teeth, but it also had some ape-like features including relatively long arms and a strongly sloping face that juts out from underneath the braincase with a pronounced jaw.
The pelvis, femur (upper leg), and foot bones of Au. africanus indicate that it walked bipedally, but its shoulder and hand bones indicate they were also adapted for climbing.
Homo habilis
2.4 to 1.4 million years agoEastern and Southern AfricaThis species, one of the earliest members of the genus Homo, has a slightly larger braincase and smaller face and teeth than in Australopithecus or older hominin species. But it still retains some ape-like features, including long arms and a moderately-prognathic face.Its name, which means ‘handy man’, was given in 1964 because this species was thought to represent the first maker of stone tools. Currently, the oldest stone tools are dated slightly older than the oldest evidence of the genus Homo.
Homo rudolfensis
1.9 to 1.8 million years agoEastern Africa (northern Kenya, possibly northern Tanzania and Malawi)A large cranial capacity consisting of 775 cubic centimeters, which is considerably above the upper end of H. habilis braincase size.
Larger braincase, longer face, and larger molar and premolar teeth.
H. rudolfensis didn’t have the heavily-built jaw and strong jaw muscle attachments seen in robust early humans.
Different diets between H. rudolfensis and earlier australopith species capable of more powerful chewing.
Like other early Homo species, Homo rudolfensis may have used stone tools process their food.
There is fossil evidence that this species cared for old and weak individuals. The appearance of Homo erectus in the fossil record is often associated with the earliest handaxes, the first major innovation in stone tool technology (Smithsonian, 2021).
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Male Homo habilis
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Over 3 million years ago yearly, humans started to use tools. The evidence from Dikika in Ethiopia shows cut marks on the fossil bones. Tools were used to remove flesh and possibly smash bone to remove the marrow.
Early tools included twigs, sticks, and other plant materials that were easily shaped. Unmodified stones were used to process nuts.
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In early hominids, both the sacrum and hip bones are relatively short compared to apes.
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Bipedal walking was possible due to the changes in:
Reshaping the pelvis and lower limbs brings the feet and knees directly under the body’s center of gravity.The pelvis became short and wide compared to tall and narrow
Femur and tibia became slant inwards compared to straight
Knees joint could lock to maintain a straight positionFeet and toes developed into a stable platform with a spring to push off the ground.
Modification in the skull backbone created the upright body with the head directly above the backbone.The feet became curved with an arch.
Bones were short and straight compared t long and curved
The big toe was alight with other toes compared to opposable toesThe foramen magnum in the skull changed position under the skull compared to the back of the skull base.
The backbone is attached to the base of the skull.
The lower backbone is curved so the upper body sits Above the pelvis.