Looking at Human Evolution

Recall the classification system… Kingdom: Animalia Phylum: Chordata Class: Mammalia Order: Primates

Order: Primates All Primates Fig. 21.02 Lemurs Tarsiers New World Suborder Prosimii Suborder Tarsiiformes Anthropoids (suborder Anthropoidea) Hominoids Hylobatidae Pongidae Hominidae New World monkeys Old World monkeys Lemurs Tarsiers Gibbons Orangutans Gorillas Chimpanzees Humans Common Ancestor of hominids Common Ancestor of hominoids (hominids and apes) Common Ancestor of anthropoids Common Ancestor of All Primates Fig. 21.02

Prosimians tarsier lemur loris lemur tarsier white face Colubus monkey http://nicoleeke.tripod.com/mainpagelemurweb.htm http://animaldiversity.ummz.umich.edu/site/resources/corel_cd/gorilla_1.jpg/view.html lemur http://www.mikebastin.com/images/cr/animals/White%20face%20monkey.jpg white face Colubus monkey Prosimians http://www.tasikria.com/images/tarsier.jpg gorilla loris http://www.kostich.com/pygmy_loris.htm

Key Primate Traits Most key primate traits are directly involved or indirectly involved in brachiation (the swinging of limb to limb in trees) free movement of upper arm in any direction able to rotate arm bones and turn hand in a semi-circle (also for brachiation) 5 digits with opposable thumb for grasping branches and manipulating food Eyes in front of face (for 3-D vision)

Characteristics of organisms classified in Order Primates: Strong and sensitive fingers Opposable thumb Brains larger proportionally Binocular (3-D) and color vision Omnivorous Usually give birth to 1 offspring at a time (allows for extended care)

But at the Family level, humans branch off from other primates Kingdom: Animalia Phylum: Chordata Class: Mammalia Order: Primates Family: Pongidae Kingdom: Animalia Phylum: Chordata Class: Mammalia Order: Primates Family: Hominidae

Our branch We are on the ANTHROPOID branch (monkeys and apes, as opposed to prosimians: lemurs and tarsiers) Prosimians probably resemble early arboreal primates.

The Naked Ape Within the anthropoids, our group is the apes. Apes include gibbons, orangutans, gorillas, and chimpanzees (two species). Traits--large brain, long arms and short legs. Capable of brachiation, but only gibbons and orangutans are primarily arboreal.

The Hominid-Ape Split Humans split from the ape line between 5 –8 mya Molecular evidence puts the split between humans and apes at about 5-8 million years ago.

Bipedality Original Explanation: Why did bipedality emerge? Original Explanation: This split between hominids and apes is thought to have resulted from the continuing drying trend, changing woodland into open plains. Any ape with a pre-adaptation for surviving in the plains would have an enormous survival advantage, and would be able to pass these traits to its offspring. Problem: many fossil humans have been found in dense woodland or wooded lakeside habitats.

Other Explanations Intrinsic: Walking upright increased the range of vision, freed the hands for gathering, allowed for holding of children while standing. Heat regulation: Standing upright vastly decreased body heating from the sun, decreasing heat stress. In this model, upright posture would have accompanied loss of body hair and the development of sweating as a means of evaporative cooling. Problem: there is at least one highly successful group of monkeys — baboons — who made the transition toward savannah lifestyle, without becoming bipedal. Also, the earliest hominids appeared to live in wooded environments much like the ones where chimps live.

Some anatomical ways we differ from Pongids:

Hand Foot Hand Foot (a) Lemur (Eulemur mongoz) (b) Tarsier (Tarsius spectrum) Hand Foot Hand Foot (c) Woolly spider monkey (Brachyteles arachnoides) (b) Gorilla (Gorilla gorilla) Fig. 21.01

So now a brief glimpse into human evolution…

Australopithecus afarensis Age: 3.9 - 3.0 mya Bipedal Small brain Large, wide teeth Most complete early hominid Possible ancestor of all later australopithecines (A. africanus, A. robustus, A. boisei, A. aethiopicus, A. garhi) http://www.rtg.wa.edu.au/loanpool/lucy.jpg art bones prints

A. afarensis: artist’s renderings http://www.gurche.com/webgraphics/ap_afar_106a_fs.jpg http://www.archaeologyinfo.com/images/afarensis.JPG

A. afarensis: skeleton http://www.wsu.edu:8001/vwsu/gened/learn-modules/top_longfor/timeline/afar ensis/images/afarensis-three-skeletons.jpeg http://www.scienceinafrica.co.za/pics/origin2a.gif

A. afarensis: footprints http://www.mnh.si.edu/anthro/humanorigins/ha/images/laetoli1.jpg http://www.modernhumanorigins.com/hominids/laetolifoot1.jpg

Paranthropus robustus Note the large (robust) cheeks, jaw, teeth, etc)

Paranthropus robustus http://anthro.palomar.edu/hominid/australo_1.htm http://www.hunterian.gla.ac.uk/collections/museum/hominid/australopithicus/ boisei_robustus/other_information/other_information2.shtml http://www.hunterian.gla.ac.uk/collections/museum/hominid/ australopithicus/boisei_robustus/other_information/other_information.shtml

Homo habilis Age: 2.3 - 1.6 mya Significantly larger brain size Clear evidence of tool use Broca’s area (essential for speech) visible in brain cast http://www.d.umn.edu/cla/faculty/troufs/anth1602/pchomoha.html

Homo habilis tools

Homo erectus Age: 1.8 - 0.3 mya First to leave Africa Traveled throughout Africa, Europe, and Asia Stone and bone tools May have used fire art bones tools travel http://donsmaps.com/hominidimages/erectus.jpg

H. erectus: skeleton http://donsmaps.com/erectus.html http://www.anthro.univie.ac.at/virtanth/evo_links/turkana%20boy.jpg http://donsmaps.com/erectus.html

H. erectus: artist’s renderings http://www.amnh.org/exhibitions/atapuerca/africa/images/19_erectus_mat_lg.jpg http://www.baa.duke.edu/Classes/course_images/Homo%20erectus.jpg

H. sapiens neanderthalensis http://www.astrosurf.org/lombry/Bio/crane-h-neanderthal-laferrassie.jpg Age: 250,000-30,000 Coexisted with H. sapiens sapiens Larger brain and body size Adapted to cold Used fire Buried dead Cared for wounded and elderly art bones range tools culture

H. sapiens neanderthalensis: artist’s renderings http://www.daviddarling.info/images/Neanderthal.jpg http://www.walespast.com/article_images/54-1l.jpg http://www.prehistory.lu/images/neand.jpg

H. sapiens neanderthalensis: skeleton http://www.amnh.org/exhibitions/atapuerca/meet.php http://www.channel4.com/history/microsites/N/neanderthal/facts/neanderthal_skeleton.html http://www.biblestudy.org/basicart/skeletns.jpg http://www.msu.edu/~heslipst/contents/ANP440/images/Kebara_2.jpg

H. sapiens neanderthalensis: culture 50,000 year old bone flute (neanderthal or modern human?) Burial site with flowers http://www.msnbc.com/news/547058.jpg http://www.msu.edu/~heslipst/contents/ANP440/images/Shanidar_4_and_6.JPG

Humans are Young As a species, Homo sapiens is only 300,000-50,000 years old. In relation to several billion year history of the earth, this is an extremely small amount of time.

H. sapiens sapiens Age: 100,000 - present Cave art, sculptures, etc. Small teeth & jaws Very high forehead, prominent chin paint sculpt http://news.nationalgeographic.com/news/2004/10/photogalleries/ homo_floresiensis_1/images/primary/flores_sapiens.jpg

H. sapiens sapiens: painting (Cro Magnon, caves in France) http://www.sanford-artedventures.com/study/images/cave_painting_l.jpg

H. sapiens sapiens: sculpture 22,000 B.C.E.--ivory http://www.tronchin.com/Art1A/lecture2.htm 22,000 - 21,000 B.C.E.--stone http://www.tronchin.com/Art1A/lecture2.htm 12,000 B.C.E.--reindeer antler http://www.talariaenterprises.com/product_lists/goddess.html

Cultural Evolution is by far the major force at work in changing humanity. Agriculuture began only about 11,000 years ago. Modern science began only about 500 years ago. The industrial revolution was 200 years ago.

One final note…humans have evolved through variation, mutation, and natural selection like all other species.And we continue to evolve today. Yet, keep in mind that evolution occurs in a branching fashion, With some paths diverging and evolving differently depending on environmental conditions, the variations that arose etc. Some paths lead to “dead ends” and those human species have gone extinct. Remember the branching tree and not a linear progression.

Hominid Family Tree H. sapiens sapiens H. sapiens neanderthalensis H. sapiens (archaic) H. erectus H. ergaster Homo habilis A. robustus A. boisei A. aethiopicus A. africanus A. garhi A. afarensis Kenyanthropus platyops Australopithecus anamensis Ardipithecus ramidus http://site.voila.fr/levolution/originehomme.htm

The End…(but not really!)