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Discover the fascinating similarities between humans and apes in terms of bones, muscles, chromosomes, and DNA, and explore the sequence of human evolution through major fossil findings. Learn about transitional fossils like Lucy and advancements in tool-making abilities. Dive into the origins of Homo sapiens and the significance of mitochondrial DNA in tracing human ancestry.
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Human Evolution BIO 1113/1114 Oklahoma City Community College Dennis Anderson
Animal Connection • Humans share many traits with animals • We are most similar to apes • Same 206 bones • All but 3 of 650 muscles the same • DNA is 98% the same • Same blood types Albino Gorilla
Comparing Chromosomes • All apes have 48 chromosomes • Chromosome bands between human (H) and chimpanzee (C) 99% the same • Fusion of two ape chromosomes formed human chromosome 2
Why are we so similar to apes? • DNA studies indicate there was a common primate ancestor to humans and chimpanzees that lived about 6 to 7 million years ago. • This primate gave rise to both the chimpanzee and the human family. 4
Sequence of Human Evolution • Hundreds of fossils of over 20 hominin species have been found • Hominins are human-like primates • bipedal • Some of the major fossils will be discussed in this presentation
Australopithecus afarensis • 3.2 million years ago • Nicknamed Lucy • Walked upright (bipedal) • Small brain • Skeleton human like • Feet • Pelvis • Upright stance
Australopithecus afarensis • Skull ape-like • Arms are long like an ape
Comparative Anatomy Lucy Gorilla Human • Gorilla pelvis adapted for knuckle walking • Human pelvis adapted for upright walking • Lucy’s pelvis is very similar to human pelvis
Knuckle Walking • Requires an elongated pelvis and long arms
Lucy’s pelvis allowed her to walk like a human instead of an ape.
Fossilized Footprints • Footprints left when a pair of Australopithecines walked in the ash of a recently erupted volcano
Lucy Chimp Skull Anatomy • Thick brow ridges like a chimpanzee • Cranial capacity 400 cc. Chimp 350 cc. • Teeth similar to human teeth
Lucy: A Transitional Fossil • Transitional fossil shows characteristics of two kinds of animals • Represent the transition from one organism to another • Ape characteristics • Skull • Cranial capacity • Human characteristics • Walked upright • Feet • Pelvis
Australopithecus africanus • 2.8 million years ago • Cranial capacity 460 cc
Australopithecus africanus • More human-like body than Lucy • Cranial features more human-like
Homo habilis • Cranial capacity 630 cc • Flatter face than Australopithecines
Homo habilis • Made and Used tools • Nicknamed handy man
Homo ergaster • 1.9 million to 1.4 million years ago • 700-850 cc cranial capacity • Large brow ridges
Homo ergaster • Skeleton very similar to modern man • 6 feet 3 inches tall • Working Man • More advanced tools than H. habilis • Hand axes • Cleavers • Used fire
Homo erectus 1.8 million to 35,000 years ago 1,000 cc cranial capacity Large brow ridges Sloping forehead
Homo neanderthalensis • 200,000 to 25,000 years ago • Cranial capacity up to 1750 cc • Larger than modern man • No chin • Sloping forehead
Homo neanderthalensis • Skeleton more robust than modern man • Much stronger than modern man
Homo neanderthalensis • Made tools and weapons • Buried dead with tools and flowers • Made musical instruments • Flutes
Homo sapiens • 200,000 years ago to present • Photo is a skull 35,000 years old • 1400 cc cranial capacity • Vertical forehead • Pronounced chin
Modern Homo sapiens • Small front teeth • Small brow ridges • Rounded cranium
Homo neanderthalensis Australopithecus afarensis Australopithecus africanus Homo ergaster Homo habilis Homo erectus Common ancestor Modern apes Sequence of Human EvolutionOne of several possibilities Homo sapiens
Sahelanthropus tchadensis • 6 to 7 million years ago • Flat face like Homo • Cranial capacity about the same as a chimp • Walked upright
Evolution of Skull • Cranial capacity increases for a larger brain • Face become flatter • Brow ridges become smaller • Forehead becomes higher • Chin develops
Mitochondrial DNA • Only inherited from mother • Mutates faster than nuclear DNA • Lacks repair enzymes
Mitochondrial DNA • Studied in several different human populations • Greatest diversity found in African population • Therefore the oldest population • Molecular clock
Mitochondrial Eve • Mother of all humans • She lived about 200,000 years ago in Africa
Native American Origin • Four rare mtDNA haplotypes are found in Native Americans • The same haplotypes are found in Mongolia and China