Human Evolution

6,000,000,000 years ago… Human evolution is the lengthy process of change by which people originated from apelike ancestors. Scientific evidence shows that the physical and behavioral traits shared by all people originated from apelike ancestors and evolved over a period of approximately six million years. Bipedalism – The ability to walk on 2 legs. One of the earliest defining human characteristics. Etymology: bi = 2; ped=foot

“Did we come from monkeys?” Humans are primates. Primates are an order of mammals that have: Forward facing eyes Binocular vision Bony ridge above the eye socket A large domed cranium to protect the brain 5 fingers, opposable thumbs, keratin nails (not claws) According to physical characteristics and genetics, Homo sapiens are closely related to the primate group, the Ape (chimpanzees and gorillas).

Grandparents or cousins? This cladogram shows that we are closely related to chimpanzees and that we share an ancient common ancestor (5 -8 mya)with them. So, NO, we did not evolve from monkeys.

Out of Africa Human migration map Humans first evolved in Africa and most of human evolution happened in Africa. The fossils of early humans come from Africa from between 6 – 2 million years ago. There have been between 15-20 different human species. Early humans migrated out of Africa, into Asia, 1.8 – 2 million years ago. The beginning of agriculture and civilization occurred in the past 12,000 years. Human migration map

Evidence Early remains provide clues into our past. These remains include: bones, teeth, tools, footprints, hearths, butchery marks on animal bones. By studying fossil remains scientists learn about the appearance, habits, and how they changed over time. Scientists study: bone and tooth size, shape, marks left by muscles, and brain size to learn how early man moved around and held / used tools.

Fossil Bones Scientists have fossils from over 6000 individuals. There were times in the past when 3 or 4 human species lived at the same time! How do we know how old fossils are? Dating fossils Sahelanthropus tchadensis, nicknamed Toumai, walked upright, in Chad, 6-7 million years ago, which many scientists consider a key characteristic that distinguishes hominids from non-human primates.

Lucy Lucy was found in Ethiopia in 1974. She belongs to the species Australopithecus afarensis. Her femur, knee, pelvis, spine and big toe all provide evidence that Lucy was bipedal. She has one bite mark on her hip from a carnivore. Lucy was dated using argon-argon, paleomagnetic, paleontological, and sedimentological studies, researchers date Lucy to less than 3.18 million years old. She was about three-and-a-half feet tall, and weighed about 60 to 65 pounds. Lucy may have been a human ancestor.

Taung Child The Taung child is a fossil from the species Australopithecus africanus, found in 1924 in Taung, South Africa. The fossil is about 2.5 million years old. The skull shows that it would have been positioned directly above the spine, meaning it was bipedal. Based on studies of the tooth enamel, the boy was about 3-4 years old, 3 ½ feet tall and about 20-24 lbs. The boy was likely killed by an eagle due to the damage to the skull and eye socket.

Turkana Boy Turkana boy was found in 1984 near Lake Turkana in Kenya. He was about 8 - 12 years old and is the most complete fossils of Homo erectus from 1.6 million years ago. Except for his skull, his bones are very similar to a modern boy.

Neanderthals Neanderthals lived 40,000-400,000 years ago and are our closest extinct relative (we share 99.7% of our DNA). Neanderthals had a short, wide body and large brains. Neanderthals made tools, built fires, had language and social groups. Neanderthals and Homo sapiens (us) lived together for about 5,000 years and sometimes mated and produced offspring.

Great resources http://humanorigins.si.edu/evidence/human-evolution-timeline-interactive http://humanorigins.si.edu/evidence/human-fossils/species http://humanorigins.si.edu/evidence/human-family-tree http://humanorigins.si.edu/evidence/3d-collection/fossil

Resources used http://humanorigins.si.edu/education/introduction-human-evolution https://iho.asu.edu/about/lucys-story https://www.wikipedia.org/