Hominid Evolution

Monkeys Hominins are organisms that is more closely related to a human than a chimpanzee – Chimps are our closest relative of the primates There is a large amount of confusion about their origin To understand where we came from we have to understand where they came from

Monkeys Humans are a member of the order primates This means we have opposable thumbs, flexible hips and shoulders, forward facing eyes and increased sensory processing abilities Primates are generally found in the tropical or sub tropical regions of Asia, Africa or South America

Monkeys A common misconception is that humans evolved from monkeys Monkeys are their own branch in the order of primates Old World monkeys (Asia and Africa) were the first to evolve They do not have a prehensile tail and their nostrils open downward

Monkeys New World monkeys are found in the Americas and probably traveled to those locations on logs and debris NWM have prehensile tails, wide set nostrils and are all tree dwelling

Apes The remaining primates are “Apes” Lesser Apes are gibbons and Siamangs These are classified as hylobatidae These are smaller, have more slender limbs and have less sexual dimorphism than their other ape counterparts

Apes Great Apes are classified as the sub order homininea These include orangutans, gorillas, chimps and humans These all lack tails, large brain size compared to body size, have broad flat faces and a socialized culture

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Hominins There have been 20 species of hominins that have been discovered through evolutionary history Each and every one has been more related to humans than chimps

Hominins Since hominins only appeared 7 million years ago, there were several periods where several hominin organisms appeared at once on the earth However many of those species died out Around one million years ago there was only the homo genus left

The Starting Lineup There were many discoveries along the line to understanding human evolution There are several different genus and species that are well researched or particularly important

The Starting Lineup The Australopithecus genus is a genus of extinct bipedal organisms with a smaller brain Evidence that they were bipedal comes from their hip joints, their spinal chord position and limb position

The Starting Lineup The genus homo is a collection of great apes that are characterized by the evolution of larger brains Brain size relative to body size can be an indicator of intelligence However it does matter how the brain is developed and shaped

The Major Players Australopithecus afarensis appeared roughly 4 million years ago They had small brains, a protruding face and walked upright Probably lived in small social groups like modern apes Most famous fossil is “Lucy”

The Major Players Homo erectus means “upright man” Appeared around 1.9 million years ago Much larger brain size than habilis (940cc avg) Thought to be a hunter that used tools to help Evidence of the use of fire, however no evidence of cooking First evidence of leaving Africa

The Major Players Homo habilis stands for “handy man” Appeared around 2.2 million years ago Smallish brain size (510cc – 690cc) Well known for mastering a set of stone tools that allowed them to be more successful in their environment Thought to be a scavenger instead of a hunter

The Major Players Homo neanderthalensis had a massive brain size (1600cc avg) However it was structured differently than ours.3% difference in DNA (that is two times larger than the largest human gap) Ranged from Europe to Central Asia Possible cause of many or modern traits Probably driven extinct by modern humans

Major Players Homo sapiens means “thinking man” Brain size averages 1350cc Characterized by a large brain and a complex social environment Amazing ability to alter their ability to alter the environment

Frontal Lobe The large and complex frontal lobe is theorized to be on of the major reasons for the survival of homo sapiens It is the center that allows us to have complex thought, metacognition and complex planning This allows Homo sapiens to have the ability to live in many different environments

Frontal Lobe Many studies have been done on people with damaged frontal lobes The most famous is Phineas Gage He damaged his frontal lobe while working on a train track Later his doctors reported he had difficulty keeping plans, use very profane language, and had little ability to balance his “intellectual faculties and animal propensities”