Human Evolution

I. What are humans related to?

Human Evolution I. What are humans related to? - Morphologically similar to apes

Human Evolution I. What are humans related to? - Morphologically similar to apes - hands, binocular vision (Primates) No tail

Human Evolution I. What are humans related to? Apes

Human Evolution I. What are humans related to? Apes II. How do we differ?

Human Evolution I. What are humans related to? Apes II. How do we differ? - Behaviorally (walk erect)

Human Evolution I. What are humans related to? Apes II. How do we differ? - Behaviorally (walk erect) - Behaviorally (intelligence and learning)

Human Evolution I. What are humans related to? Apes II. How do we differ? - Behaviorally (walk erect) - Behaviorally (intelligence and learning) - Morphologically, humans have: - larger head/body ratio

Human Evolution I. What are humans related to? Apes II. How do we differ? - Behaviorally (walk erect) - Behaviorally (intelligence and learning) - Morphologically, humans have: - larger head/body ratio - smaller jaw/head ratio

Human Evolution I. What are humans related to? Apes II. How do we differ? - Behaviorally (walk erect) - Behaviorally (intelligence and learning) - Morphologically, humans have: - larger head/body ratio - smaller jaw/head ratio - shorter arms/body ratio

Human Evolution I. What are humans related to? Apes II. How do we differ? - Behaviorally (walk erect) - Behaviorally (intelligence and learning) - Morphologically, humans have: - larger head/body ratio - smaller jaw/head ratio - shorter arms/body ratio - less hair

Human Evolution I. What are humans related to? Apes II. How do we differ? - Morphologically Human Chimp Gorilla Orangutan Gibbon

Human Evolution I. What are humans related to? Apes II. How do we differ? - Genetically: Big Surprize! Human Chimp Gorilla Orangutan Gibbon

Human Evolution I. What are humans related to? Apes II. How do we differ? - Genetically: Big Surprize! Human Chimp Gorilla Orangutan Gibbon < 1% difference in gene sequence

Human Evolution I. What are humans related to? Apes II. How do we differ? III. Resolution? Can this 1% difference account for the dramatic behavioral and morphological differences we see?

Human Evolution I. What are humans related to? Apes II. How do we differ? III. Resolution? Can this 1% difference account for the dramatic behavioral and morphological differences we see? Yes, some genes have big effects. These are regulatory genes, acting during development. They influence the expression of lots of other genes…

Human Evolution I. What are humans related to? Apes II. How do we differ? III. Resolution? Can this 1% difference account for the dramatic behavioral and morphological differences we see? Yes, some genes have big effects. These are regulatory genes, acting during development. They influence the expression of lots of other genes… - Can we test this hypothesis? Do the differences correlate with developmental effects?

- Yes. All differences correlate with developmental differences between juvenile primates and adults… Juveniles Adults Larger Head/body ratiosmaller Smaller jaw/head ratiolarger Shorter limb/body ratiolonger Less hairmore hair Better learningpoorer learning

- Yes. All differences correlate with developmental differences between juvenile primates and adults… Juveniles Adults Larger Head/body ratiosmaller Smaller jaw/head ratiolarger Shorter limb/body ratiolonger

- Yes. All differences correlate with developmental differences between juvenile primates and adults… Juveniles Adults Larger Head/body ratiosmaller Smaller jaw/head ratiolarger Shorter limb/body ratiolonger Less hairmore hair Better learningpoorer learning Human-likeApe-like

Human Evolution I. What are humans related to? Apes II. How do we differ? III. Resolution? Can this 1% difference account for the dramatic behavioral and morphological differences we see? Yes, if the small change is in developmental genes, they can have BIG effects…humans might be a type of ape that didn’t grow up… The ways we differ supports this hypothesis…

Yes, if the small change is in developmental genes, they can have BIG effects…humans might be a type of ape that didn’t grow up… Primate developmental trajectory Chimp Small changes in development, especially if they occur early in development, can result in big effects. Human

What are some of these genetic differences? The HAR1 RNA molecule. - not a coding RNA; probably regulatory BeniaminovBeniaminov A, Westhof E, and Krol A WesthofKrol Distinctive structures between chimpanzee and human in a brain noncoding RNA. RNA 14:

What are some of these genetic differences? The HAR1 RNA molecule. - not a coding RNA; probably regulatory - nearby genes associated with transcriptional regulation and neurodevelopment are upregulated in humans. BeniaminovBeniaminov A, Westhof E, and Krol A WesthofKrol Distinctive structures between chimpanzee and human in a brain noncoding RNA. RNA 14:

What are some of these genetic differences? The HAR1 RNA molecule. - not a coding RNA; probably regulatory - nearby genes associated with transcriptional regulation and neurodevelopment are upregulated in humans. - only 2 changes in sequence between chicks and chimps; 18 between chimps and humans… “HAR” stands for “human accelerated region” – changing more rapidly than drift can explain… why? Selection. BeniaminovBeniaminov A, Westhof E, and Krol A WesthofKrol Distinctive structures between chimpanzee and human in a brain noncoding RNA. RNA 14:

What are some of these genetic differences? The HAR1 RNA molecule. - not a coding RNA; probably regulatory - nearby genes associated with transcriptional regulation and neurodevelopment are upregulated in humans. - only 2 changes in sequence between chicks and chimps; 18 between chimps and humans… “HAR” stands for “human accelerated region” – changing more rapidly than drift can explain… why? Selection. -Changes result in a profound change in RNA structure and, presumably, binding efficiency. BeniaminovBeniaminov A, Westhof E, and Krol A WesthofKrol Distinctive structures between chimpanzee and human in a brain noncoding RNA. RNA 14:

Two distinct experimentally supported secondary structure models for HAR1 RNAs. Beniaminov A et al. RNA 2008;14: Copyright © 2008 RNA Society HUMAN CHIMP

Human Evolution I. What are humans related to? Apes II. How do we differ? III. Resolution? IV. Are there common ancestors?

Human Evolution I. What are humans related to? Apes II. How do we differ? III. Resolution? IV. Are there common ancestors? Yes. Just where evolution predicts they should be (After other monkeys and apes, before humans and existing apes).

Molecular clock analyses

Science, Nov 19, 2004 Pierolapithecus catalaunicus mya: oldest ‘great ape’

‘apes’ – no tail

V. Are there common ancestors? - Fossil and genetic analysis independently predicted a common ancestor between humans and chimps lived 5-8 million years ago. Chimpanzee Human Homo sapiens

V. Are there common ancestors? - Fossil and genetic analysis independently predicted a common ancestor between humans and chimps lived 5-8 million years ago. Chimpanzee Human Homo sapiens Sahelanthropus tchadensis – discovered in Chad in Dates to 6-7 mya. Only a skull. Is it on the human line? Is it bipedal? Probably not (foramen magnum). Primitive traits, as a common ancestor might have.

Human Evolution I. What are humans related to? Apes II. How do we differ? III. Resolution? IV. Are there common ancestors? V. Are there intermediate links to modern humans?

- yes, and in a nearly continuous sequence…. Chimpanzee Human Homo sapiens Australopithecus afarensis Australopithecus africanus Homo habilis Homo erectus

V. Are there intermediate links to modern humans? - with a divergence of two types of hominids around 2 mya

V. Are there intermediate links to modern humans? - with a divergence of two types of hominids around 2 mya

V. Are there intermediate links to modern humans? - with a divergence of two types of hominids around 2 mya “slender” species

V. Are there intermediate links to modern humans? - with a divergence of two types of hominids around 2 mya “slender” species “robust” species

V. Are there intermediate links to modern humans? - with a divergence of two types of hominids around 2 mya Primitive, bipedal species

Orrorin tugenensis: mya. Discovered in 2000 by Brigitte Senut. Processes on femus suggest bipedality in this forest-dwelling species, refuting the savannah-bipedality link. Some suggest the femur is more humanlike than those of Australopithecines, suggesting those are a side group in human evolution.

Ardipithecus kadabba: 5.6 mya. Discovered in 2004 by Haile-Sailasse, Gen Suwa, and Tim White. Initially thought to be chronospecies of A. ramidus, tooth size in recent fossils suggested a new species.

Ardipithecus ramidus: mya. Discovered in 1994 by Haile-Sailasse, Suwa, and White, with the most complete fossils were not described until Arboreal, but facultatively bipedal. Grasping toes.

Australopithecus anamensis: mya. About 100 fossils, from an estimated 20 individuals; all from the Lake Turkana region of east Africa. Found in 1965, 1987, 1995, and 2006, it was only in 1995 when Meave Leakey distinguished it from other Australopithecine species. Probably the direct ancestor of A. afarensis. Dr. Meave Leakey is spouse of Dr. Richard Leakey, son of Louis and Mary Leakey – discoverers of several ancient hominids at Olduvai Gorge.

Australopithecus afarensis: mya. A femur discovered in 1973 by Donald Johansson suggested an upright gait, confirmed by his discovery in 1974 of the ‘Lucy” specimen. Also, the Laetoli prints (found by Mary Leakey) were probably made by A. afarensis, and in 2006, a juvenile A. afaresis was found.

And, as we’ve discussed, Australopithecus afarensis walked erect.

A. Afarensis prints at Laetoli, approximately 3.56 myr, were made by an obligate biped: - heel strike. - Lateral transmission of force from the heel to the base of the lateral metatarsal. - A well-developed medial longitudinal arch. - Adducted big toe, in front of the ball of the foot and parallel to the other digits. - A deep impression for the big toe commensurate with toe-off.

Australopithecus bahrelghazali: 3.6 mya; discovered in Chad in 1993 by Michel Brunet – who won’t release it for others to study. Most paleontologists suggest it is within the range of variation for A. afarensis.

Kenyanthropus platyops: mya – Discovered by Meave Leakey’s team at Lake Turkana; most dispute it warrants another genus, and some even include it in A. afarensis.

Australopithecus africanus: 2-3 mya, discovered by Raymond Dart in South Africa in 1924 – the ‘Taung child’. Then, in 1947, Robert Broom found a skull he classified as Plesianthropus, but was grouped with A. africanus.

Australopithecus garhi: mya; discovered by Asfaw and White in 1996, but the skull below was discovered by Haile-Selasse in The tooth morphology is a bit different from A. afarensis and A. africanus, being much larger than even the robust forms. There are associated stone tools!

Australopithecus sebida: 1.9 mya, describe in 2010 by LE Berger; it has many characteristics like A. africanus, but also similar to genus Homo.

Paranthropus aethiopicus: mya, discovered by Alan Walker and Richard Leakey, the “black skull” is one of the most imposing hominid fossils there is! Aside from the high cheekbones and the sagittal crest, it has similar proportions to A. afarensis and is probably a direct descendant. It probably gave rise to the “robust” lineage of Paranthropus.

Paranthropus boisei: mya. Discovered by Mary Leakey in Olduvai Gorge in 1959, it was originally classified as Zinjanthropus and nicknamed “Zinj” or “nutcracker man” because of the large grinding molars.

Paranthropus robustus: mya. Discovered in South Africa in 1938 by Robert Broom.

Homo habilis: mya, discovered by Louis and Mary Leakey, in association with stone tools. “Handy man”. Longer arms and smaller brain than other members of the genus.

Homo rudolphensis: 1.9 mya; Discovered by Richard and Meave Leakey’s team. Different from H. habilis, yet a contemporary. Either may be ancestral to recent Homo.

Homo georgicus: 1.7 mya; the oldest hominid fossils found outside of Africa – found in Dmanisi, Georgia, in Thought to be a potential intermediate between H. habilis and H. ergaster/H. erectus.

Homo ergaster (H. erectus): mya, the most complete fossil hominid skeleton was discovered in 1984 by Alan Walker who called it “Turkana Boy”. Some consider this species intermediate to H. habilis and H. heidelbergensis/H. sapiens, leaving H. erectus as a distinct Asian offshoot of the main line to H. sapiens. However, most paleontologists suggest that H. ergaster is the African ancestor – even a chronospecies or population - of H. erectus, which is ancestral to more recent Homo species.

Homo erectus: mya; originating in Africa, but then leaving for Asia (Peking and Java Man). Discovered in Java by Eugene Dubois in Certainly one of the most successful hominid species in history; perhaps lasting as relictual species on islands in Indonesia as: Homo floresiensis: 94,000-13,000 years, discovered by Mike Mormood on the island of Flores. Shoulder anatomy is reminiscent of H. erectus, but could be an allometeric function of the small size (3 ft).

Homo cepranensis: 350, ,000 years old; discovered by Italo Biddittu in 1994 in Italy. It is just a skull cap, but seems to be intermediate between H. erectus and H. heidelbergensis.

Homo antecessor: 800, mya; fossils from 20 individuals found in Spain in ; may be H. heidelbergensis or an intermediate between it and H. ergaster. Homo heidelbergensis: ,000 in Europe and Africa; ancestral to H. neaderthalensis and H. sapiens; may have buried their dead. Homo rhodesiensis: ,000; may be H. heidelbergensis or intermediate to it and H. sapiens.

Homo neaderthalensis: 30, ,000; first discovered in Descended from H. heidelbergensis. Homo sapiens idaltu: 160,000 – oldest Homo sapiens fossil – found in Africa in 2003… afar valley.

VIII. And what of our species? - From Africa 200,000 years ago (earliest fossils, genetic variability, etc.) (Brazil)

VIII. And what of our species? - From Africa 200,000 years ago (earliest fossils, genetic variability, etc.) - Bands of hunter gatherers

VIII. And what of our species? - From Africa 200,000 years ago (earliest fossils, genetic variability, etc.) - Bands of hunter gatherers - Cave Art about 30,000 years ago

VIII. And what of our species? - From Africa 200,000 years ago (earliest fossils, genetic variability, etc.) - Bands of hunter gatherers - Cave Art about 30,000 years ago - 14,000 years ago, bands settled in different areas of the globe and began to grow local crops. First Agricultural Revolution….

Where and when: Sahel? West Africa? Ethiopia ? Fertile Crescent China New Guinea Andes Amazon? Mesoamerica Eastern U. S.

5.0 mya 1.75 mya tools art 0.2 mya burial 75,000 agricultur e 14,000 …to chimps 99.6% before art HUMAN PREHISTORY – Where did humans come from?

And Now… The Anthropocene: - 14,000 years to present. Score of human impact due to land transformation, soil, water, and air quality. (Each biome has it’s own scale, however, so they are not explicitly comparable).