Review for Q2

PLANETARY ORIGINS

origin myth

big bang -15 billion years ago

Georges de Buffon (1808-1877) proposed the first of the second-body theories in 1750.

In 1755, Immanuel Kant (1724-1804) -- planets were solidified masses of gas from a rotating nebula.

Pierre Laplace (1749-1827),a French mathematician - a rotating gas cloud would spin faster as it contracted, leaving rings of gases behind that could form planets.

Earth, consolidated about 4.5 billion years ago - earth's mantle = between 4.65 b.y. and 4.43 b.y before present. /Iron catastrophe

Precambrian /Atmospheric gases from earth's crust (largely by volcanic action) -carbon dioxide, water, nitrogen, and sulpher.

Little or no free oxygen in the primitive earth atmosphere

The early planet was severely bombarded by debris

Archean eon formation of some of the modern continents, and more important, the appearance of life.

The oldest known earth rock unit= Isua Supracrustal deposits of western Greenland, 3.8 billion years old,

Warrawoona Group of Western Australia- 3.5 b.y. before present fossil organisms usually are one of three types:

(a) stromatolites,

(b) sandstone impressions of large organisms

(c) microfossils.

cyanobacteria /Fossilized stromatolites - 3.5 billion years ago.

autotrophs, organisms that manufacture food with CO2 as its only carbon source

heterotrophs, organisms that forage for food upon other organisms or upon organics of cosmic origins.

oxygen-generating photosynthesis /O2 levels appear to be relatively low in earth's atmosphere until about 2.5 bya .

In the modern world, green plants generate a volume of O2 equal to our planetary atmosphere every 2,000 years.

respiration-A gram of sugar produces 3900 calories

fermentation -A gram of sugar produces 110 calories

sexual reproduction - promoting genetic recombination.

eukaryotic cell- 1.5 billion years ago

Three major lineages, archaebacteria, eubacteria, and eukaryota, developed from a single progenote.

first metazoans-less than 670 MYBP.

Paleozoic Era /shell armor - brachiopods and gastropods.

trilobites Seaweeds, sponges, jellyfish, and sea anemones

All major phyla of modern organisms have appeared.

The Permian period saw reptiles diversify and the first mammal-like reptiles appear.

The end of the Paleozoic is marked by trauma. Continental collisions

Mass extinctions - "time of the great dying" - 230 million years ago.

the asteroid hypothesis /A vast area of volcanic basalts (340,00 km2), the "Siberian Traps," - Northern Soviet Union. -240 million years ago - near the Permian Triassic boundary.

Mesozoic Era / Life rebounded from Permian extinction event and diversifies. The Jurassic is an age of gigantic marine reptiles and dinosaurs.

The first true mammals, small mouse-like and shrew-like animals from the Triassic of Europe, China, and Africa

Pangaea -Tethys sea /Flowering plants expanded greatly in the Cretaceous, and both marsupial and placental mammals appear.

The great extinctions at the close of the Mesozoic era /What killed the dinosaurs?

1.Collision of earth with a comet or asteroid that disrupted earth climate

2.Volcanic eruptions, especially those represented by Cretaceous volcanic basalts from India

3."Smarter" mammals out-competed the dinosaurs

4.Mammals ate the dinosaur eggs

5.The evolution of angiosperms was accompanied by the evolution of new plant alkaloids that were toxic (poisonous) to dinosaurs

6.Sex determination failure in a cooler environment

Cenozoic Era

The present circumantarctic currents, glaciered poles, warm tropics and drier temperate zones are progressively established.

Continents separate, isolating Australia and South America.

On land archaic mammals dominate from the Paleocene and peak in diversity during the Pliocene.

The Pleistocene Epoch witnesses the emergence of humanity as the dominant mammal.

Extinctions

The earliest documented fossil extinction occurred near the end of the Cambrian (505 MYBP) and is reflected in loss of most existing families.

The second occurs at the close of the Ordovician Period (438 MYBP) and a third marks the end of the Devonian Period (360 MYBP).

The Permian extinction (248 MYBP) was the most drastic known.

A fifth extinction event terminates the Mesozoic (65 MYBP).

Migrating Continents

Pangea - 250 million years ago provides a common planetary habitat for early reptiles and mammal-like reptiles

NONHUMAN PRIMATES

Mesozoic primates were one of the early branches of the mammalian adaptive radiation that developed after the Jurassic. The first primate adaptive radiation produces a diverse array of 'archaic primates' that date from late Cretaceous through Eocene

Archaic primates - Suborder Plesiadapiformes

Purgatorius-Cretaceous deposits of Purgatory Hill in Montana

Their fingers terminate in claw-like nails

Large infraorbital fossae -vibrissae. /Eyes are relatively small -vision are generally directed laterally as well as forward /Orbit lacks a postorbital bar /Mesial incisors often markedly procumbent

Angiosperms (flowering plants) - Early Cretaceous. Insect pollinators and flowering plants (flowers, fruits, buds, gums, nectars, leaves, bark, and pollen)

Late Paleocene -large fruits

The second adaptive radiation - dispersal of prosimian-like primates, represented by two families, Adapidae and Omomyidae.

The third radiation is represented by the earliest anthropoid grade of primate evolution , the Oligopithecinae represented by Catopithecus and Proteopithecus.

Euprimates - nails on their digits -an opposable hallux (first toe) -postorbital bar shields -fields of vision are oriented more forward. / These early euprimates are small omnivores that eat gum and search for nectar, small fruits and insects in the terminal branches of trees.

Eocene euprimates in the families Adapidae and Omomyidae achieve a prosimian grade of development

Adapis

Smilodectes

Omomyids - brain is larger-the infraorbital foramen is small-postorbital closure- face is relatively short.

Eocene Oligopithecinae -Catopithecus has anthropoid characters such as complete postorbital closure, metopic fusion, and an intraorbital lacrimal foramen. Prosimain-like characters include small body size, relatively small brains, emphasis on olfaction (evidenced by relatively broad intraorbital region), and prosimian-like shearing crests on their molar teeth.

Euprimate faunas of major continental regions diverge with the opening of the Atlantic barrier during the Eocene

Africa and Europe continue to be separated by the Tethys Sea.

The Eocene ends with a great discontinuity -the majority of the Eocene mammalian genera abruptly become extinct and with them the last of the archaic primates that had survived into the Eocene.

The Oligocene -Fayum Depression of Egypt

The anthropoid grade of primate evolution is more numerous in Oligocene Primates /Skull assumes its modern configuration with postorbital closure, a fused mandibular symphysis, a fused metopic suture. Grasping hands of anthropoids do not bear a grooming claw. Eye-hand coordination seems emphasized as the hand replaces the face as an organ for tactile exploration. Fingers are elongated. Orbits face forward, with overlapping fields that could form the basis for anthropoid stereoscopic vision.

In the Americas, anthropoids (Platyrrhines) may have evolved from early euprimate stock independently of parallel events in the Old World or share a common ancestry with an Eocene anthropoid such as Catopithecus prior to the Atlantic Barrier. New World anthropoids differ in some anatomical characteristics. Platyrrhines, New World anthropoids, retain a more primitive dental formula:

2 1 3 3

2 1 3 3

Catarrhines, Old World anthropoids, have lost the second premolar, retaining the third and fourth premolars of their early mammalian progenitors:

2 1 2 3

2 1 2 3

Platyrrhines-ectotympanic ring

Catarrhines -ossified ectotympanic tube

Catopithecus, lacks a Catarrhine ectotympanic tube but has a Catarrhine dental formula.

The Miocene and Pliocene witnessed a radiation of anthropoids in both the Old and New World continents The anthropoid adaptive radiation continues with appearance of Hominoidea and Cercopithecoidea.

Hominoids are easily recognized by a characteristic molar anatomy, the dryopithecine pattern

The middle and late Miocene of Africa is thought to have drier climate, a change in environment that discouraged frugivores and is marked by the presence of hominoids whose molars exhibit increased enamel thickness and by an increase in the number of old world monkey genera.

The middle Miocene radiation of cercopithecoids is thought to reflect a dietary specialization toward omnivory in the drier forests.

The late Miocene marks the beginnings of the radiation of the Hominidae, the humans.

Near the end of the Miocene, a dramatic lowering of sea level occurred,leaving the Mediterranean Sea a land-locked basin that dried up, opening dry-land connections between Africa and Europe.

The African continental plate impacted the smaller Arabian plate about 16 million years ago, and Arabian fossil faunas are similar to North East Africa at that time. The Arabian plate continues to move counterclockwise away from Africa to produce the Gulf of Aden rifts.

Four families of Miocene apes are generally recognized: Proconsulidae, Oreopithecidae, Pliopithecidae, and Pongidae.

Early Miocene hominoids are best known from East African Proconsulidae, whose species vary in size from about 3 kg to over 50 kg.

Proconsul africanus- Rusinga Island, Kenya.

Others:

Dendropithecus

Micropithecus

Oreopithecus bambolii -14 million years ago.

The Pliopithecidae are a group of small gibbon-sized apes from Europe and Asia with primitive looking molar teeth.

Pliopithecus

The Pongidae are a quite variable group of apes who, among other features, have upper canine teeth that exhibit less honing function on P3.

Ankarapithecus meteai - 10 million years ago

Dryopithecus

Sivapithecus

Ouranopithecus

Gigantopithecus

Afropithecus

Kenyapithecus

Turkanapithecus

PLIOCENE AND EARLY PLEISTOCENE HUMANS

Australopithecus (Dart, 1925)

Australopithecus ramidus. White, Suwa & Asfaw, 1994

Date: 4.4 MYBP

Distribution: Africa

Sites: Aramis Synonyms:

Ardipithecus (Dart, 1925)

Australopithecus anamensis

Date: 3.9 to 4.2 MYBP

Distribution: Africa

Sites: Kanapoi

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Australopithecus afarensis (Johanson, White, and Coppens, 1978)

Date: 5 to 3 MYBP

Distribution: Africa Sites: Baringo, Hadar ( AL 162, AL 288, AL 200), Laetoli, Lothagam, Turkana ______________________________

Australopithecus africanus (Dart, 1925)

Date: 3 to 2 MYBP

Distribution: Africa (Sites: Makapansgat (MLD 1, MLD 37/38), Olduvai Bed I, Sterkfontein (Sts 5), Taung, Turkana (Omo) Synonyms: Plesianthropus transvaalensis (Broom 1938); Australopithecus. prometheus (Dart, 1949)

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Australopithecus robustus (Broom, 1938)

Date: 2 to 1.5 MYBP

Distribution: Africa Sites: Kromdraai, Swartkrans (SK 46, SK 48,) Synonyms: Paranthropus robustus (Broom, 1938); Paranthropus crassidens (Broom, 1949)

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Australopithecus boisei (L. Leakey, Tobias, and Napier, 1964)

Date: 2.8 to 1.4 MYBP

Distribution: Africa Sites: Olduvai Gorge (OH 5), Peninj, Lake Turkana (KNM-ER 406, KNM-ER 732, KNM-WT 17,000) Synonyms: Paraustralopithecus aethiopicus (Arambourg and Coppens), 1968; Homo aethiopicus (Olson, 1985)

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Homo (Linnaeus, 1758)

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Homo habilis (L. Leakey, Tobias, and Napier, 1964)

Date: 2.4 to 1.5 MYBP

Distribution: Africa

Sites: Laetolii, Olduvai (OH 13, OH 24, OH62); Omo; Sterkfontein Extension (Stw 53); Turkana (KNM-ER 1470, KNM-ER 1590, KNM-ER 1813) Synonyms: Telanthropus capensis (Robinson, 1953)

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PLEISTOCENE HUMANS

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Homo erectus (Dubois, 1892)

Date: 1.8 to 0.2 MYBP

Distribution: Africa, Europe, Asia Sites: Chenchiawo; Hexian; Mauer; Modjokerto; Olduvai [O.H.9; O.H. 12]; Omo; Sangiran [#4; 17]; Salé; Ternifine; Tiblitz, Trinil; Turkana [East: KNM-ER 1808, 3733; 3883; West: KNM-WT 15000]; Zhoukoutian (Lower cave) Synonyms: Pithecanthropus erectus (Dubois 1893); Hylobates giganteus (Bumuller, 1899); Sinanthropus pekinensis (Black and Zdansky, 1927); Homo modjokertensis (von Koenigswald, 1936); Atlanthropus mauritanicus (Arambourg, 1954); Homo leakeyi (Heberer, 1963); Tchadanthropus uxoris (Coppens, 1965); Homo ergaster (Groves and Mazak, 1975)

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Homo sapiens (Linnaeus, 1758)

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Homo sapiens soloensis (Oppenoorth, 1932)

Date: ca 400,000 to 100,000 YBP

Distribution: Africa, Asia, Europe Sites Arago {#21]; Dali; Laetoli [L. H. 18]; Mapa; Ndutu; Ngandong [#7]; Omo [Omo 2]; Steinheim; ?Swanscombe Synonyms: Homo sapiens steinheimensis (Berckhemer 1936), Homo primigenius asiaticus (Weidenreich, 1932 nec Linnaeus, 1758)

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Homo sapiens rhodesiensis (Woodward, 1921)

Date: ca 0.4 to 0.1 MYBP

Distribution: Africa, Europe Sites: Bodo, Elandsfontien; Kabwe; Petralona; ?Singa Synonyms: Cyphanthropus rhodesiensis (Pycraft, 1928), Homo kanamensis (L. Leakey, 1935), Palaeoanthropus njarensis (Reck and Kohl-Larsen, 1936), Africanthropus njarensis (Weinert, 1938)

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Homo sapiens neanderthalensis (King, 1864)

Date: 135,000 to 29,000 YBP

Distribution: Circum-Mediterranean Sites: Amud, Combe-Grenal, Devil's Tower, Ehringsdorf, Forbes' Quarry, Jebel Irhoud, Krapina, La Chapelle-aux-Saints, La Ferrassie, Le Moustier, La Quina, Monte Circeo, Neanderthal, Saccopastore, Shanidar, Tabun, Teshik-Tash Synonyms: Protanthropus atavus (Haeckel, 1895); Homo europaeus primigenius (Wisler, 1898); Paleanthropus krapiniensis (Sergi, 1911); Homo primigenius (Schwalbe, 1903); Homo antiquus (Adloff, 1908);Homo transprimigenius mousteriensis (Forrer, 1908), Homo neanderthalensis (Bonarelli, 1909);Homo priscus (Krause, 1909); Palaeanthropus europaeus (Sergi, 1910); Homo calpicus (Keith, 1911);Archanthropus (Arldt, 1915); Anthropus neanderthalensis (Boyd-Dawkins, 1926);Metanthropus (Sollas, 1933); Pithecanthropus neanderthalensis (Sklerj, 1937)

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Homo sapiens sapiens (Linnaeus, 1758)

Date: ca. 100,000 YBP to Holocene

Distribution: Africa, Asia, Europe Sites: ?Border Cave, Combe-Capelle, Cro-Magnon, Fish Hoek, Grimaldi Jebel Qafzeh [#6], Mugharet es Skhul [Skhul 5], Omo (Omo 1), Predmosti; Zhoukoutian Upper Cave, Synonyms: Homo sapiens fissilis (Gorjanovic-Kramberger, 1905); Homo grimaldii (Lapouge, 1906); Notanthropus eurafricanus recens (Sergi, 1911); Notanthropus eurafricanus archaius (Sergi, 1911); Homo mediterraneus fossilis (Behm, 1915); Homo capensis (Broom, 1917); Homo sapiens cromagnonensis (Gregory, 1921); Homo larterti (Pycraft, 1935); Palaeanthropus palestinus (McCown and Keith, 1932 in Weidenreich 1932b).

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RECONSTRUCTING HUMAN EVOLUTION

Human evolution features at least two major adaptive radiations.

The First Human Adaptive Radiation - Bipedal Pongids

A. afarensis -obligate bipedalism

The Second Human Adaptive Radiation - Tools and Material Culture

Origins of Anatomically Modern Humans (H. sapiens sapiens)

Currently there are four competing models in discussions of the appearance of Homo sapiens sapiens: MRE, RAE, AES, and RLE.

MRE

1. No single definition of modern humans will apply to all regions due to regional diversity.

2. Anatomically modern form does not necessarily have to be earlier in Africa.

3. Early modern humans in Asia will lack African features since they are not African migrants and are adapted to a different climate.

4. Unique regional anatomical features should be found earlier in the periphery of the different areas and central regions (where gene flow is more likely) will be less diverse.

5. Early modern humans should have some anatomical features derived from archaic Homo in their region.

RAE

1. Modern anatomical forms will be found earlier in Africa than other regions.

2. There will be no hybrids or intermediate forms during dispersal due to hybridization.

3. Modern anatomical form existed in Africa by 100,000 YBP.

AES

1. Modern anatomy will be found much earlier in Africa than other places.

2. Early modern populations in a region will be more "Africanized" than later locally hybridized people.

3. Modern human anatomy should be established in Africa by 100,000 YBP.

RLE

1. There will be a substantial time lapse between the appearance of morphologically modern humans and the explosive cultural dispersal characteristic of modern aptitudes.

2. Hybrid or intermediate forms might occur, but they would be quickly swamped by genotypes with modern speech and cultural abilities. Hybridization during colonization would serve to perpetuate some regional gene alleles (such as shovel-shaped incisors in Asia), but true hybrid morphologies should be rare.

3. Migration was not a single event but occurred numerous times as cultural changes destabilized adjacent populations. Gene flow should produce a pattern of high early variability that diminished with time.