Tracking Human Evolution: Where Do We Fit on the Tree of Life? Geology 230 Fossils and Evolution Phylogenetic Classification of Humans Life on Earth Eukaryota Animalia Bilateria Deuterostomia Chordata Craniata Vertebrata Gnathostomata Osteichthyes Sarcopterygii Tetrapoda Phylogenetic Classification of Humans Reptiliomorpha Amniota Synapsida Therapsida Mammalia Eutheria Primates Anthropoidea Hominidae Homo H. sapiens Tree of Life Web Project http://tolweb.org/tree/phylogeny.html Root of the Tree, Life on Earth: http://tolweb.org/Life_on_Earth/1 Eukaryotes http://tolweb.org/Eukaryotes/3 Animals, Metazoa http://tolweb.org/Animals/2374 Bilateria http://tolweb.org/Bilateria/2459 Deuterostomia http://tolweb.org/Deuterostomia/2466 Chordata: dorsal nerve cord http://tolweb.org/Chordata/2499 Exemplar fossil: Yunnanozoon or Haikouella, Cambrian Yunnanozoon (Haikouella), a cephalochordate from the Lower Cambrian of China Urochordates: Sea Squirts. Adults have a pharynx with gill slits. Larval forms are free-swimming and have a notochord. Chordates are thought to have evolved from the larval form by precocious sexual maturation. Tunicates or Sea Squirts mobile larva sessile adult Cephalochordate: Branchiostoma, the lancelet Craniata: skull http://tolweb.org/Craniata/14826 Vertebrata: vertebrae http://tolweb.org/Vertebrata/14829 A living jawless fish, the lamprey Gnathostomata: jawed vertebrates http://tolweb.org/Gnathostomata/14843 The placoderms were the armored fish of the Paleozoic. Grew up to 10 m in length. Placoderm, Dunkleosteus, Devonian of Ohio Placoderm, Devonian of Australia Osteichthyes: Bone structure in fins of ray-finned and lobe-finned fish Fish Anatomy: Lobe-finned fish Sarcopterygii: lobe-fins http://tolweb.org/Sarcopterygii/14922 Sarcopterygian, lobe-finned fish, Devonian of Scotland An Australian lungfish with well developed lobe fins Coelocanth, a living lobe- finned fish Skeleton of the coelocanth A Coelocanth Evolution of the tetrapod walking leg from the lobe fin Sauripterus, rhipidistian, Late Devonian, Pennsylvania Evolution of tetrapod legs from lobe fins, late Devonian to early Mississippian Evolution of Tetrapods Prothero, 2007 Late Devonian fin with fingers from a lobe- finned fish, Pennsylvania Tiktaalik rosea from the Late Devonian of Ellsmere Island, Canada, 2006 Tiktaalik rosea from the Late Devonian of Ellsmere Island, Canada, 2006 Tiktaalik rosea on Colbert Report Lobe-Fins to Tetrapoda: four legs http://tolweb.org/Terrestrial_Vertebrates/14952 Tetrapods: Acanthostega and Ichthyostega, Devonian of Greenland. Lobe-Fin Fish or Tetrapods? Skull roof of the Late Devonian Ichthyostega Acanthostega using its legs to lift its head out of the stagnant water to breathe Hindlimb of Ichthyostega, Devonian of Greenland Fish with Fingers, Jenny Clack Ichthyostega: Photographs of part and counterpart superimposed to show seven digits Changing Digits from the Late Devonian to Early Mississippian Reptiliomorpha http://tolweb.org/Terrestrial_Vertebrates/14952 Amniota http://tolweb.org/Amniota/14990 Crocodiles hatching from their amniote eggs Pennsylvanian anapsid or stem reptile Amniote Family Tree Prothero, 2007 Synapsid Skull: one Diapsid Skull: two opening behind the openings behind the orbit (eye) orbit (eye) Synapsida http://tolweb.org/Synapsida/14845 Permian Synapsids, Germany Triassic synapsid reptiles: Therapsids or mammal-like reptiles Therapsida, Mammals and extinct relatives http://tolweb.org/Therapsida/14973 Biarmosuchia Eotitanosuchia Dinocephalia Anomodontia Theriodontia Gorgonopsia Therocephalia Cynodontia Diviniidae Mammalia Procynosuchidae Galesauridae Thrinaxodontidae Cynognathidae gomphodonts Chiniquodontidae Probainognathidae Tritheledontidae (Ictidosauria) A Gallery of Therapsids From Synapsids to Mammals, a well documented transition series Prothero, 2007 Carl Buell Prothero, 2007 Yanoconodon, Lower Cretaceous of China Yanoconodon, Lower Cretaceous of China, retains ear bones attached to lower jaw Morganucodon Yanoconodon Mammalia http://tolweb.org/Mammalia/15040 Class Mammalia - Late Triassic to Recent Superorder Tricodonta - Late Triassic to Late Cretaceous Superorder Multituberculata - Late Jurassic to Early Oligocene Superorder Monotremata - Early Cretaceous to Recent Superorder Metatheria (Marsupials) - Late Cretaceous to Recent Superorder Eutheria (Placentals) - Late Cretaceous to Recent Evolution of Mammalian Superorders Multituberculates U Metatheria Eutheria (Marsupials) (Placentals) Tricodonts U Monotremes . Live Birth Extinct: U . .. Mammary Glands? Mammals in the Age of Dinosaurs Hadrocodium, a lower Jurassic mammal with a “large” brain (6 mm brain case in an 8 mm skull) Lower Cretaceous mammal from China Jawbones of a Cretaceous marsupial from Mongolia Mammal fossil from the Cretaceous of Mongolia Eutheria http://tolweb.org/Eutheria/15997 Primate Classification- 1980’s Order Primates Suborder Prosimii: tarsiers and lemurs Suborder Anthropoidea: monkeys, apes, and hominids Superfamily Hominoidea Family Pongidae: great apes Family Hominidae: Homo and hominid ancestors Primate Classification – 2000’s Order Primates Suborder Prosimii: tarsiers and lemurs Suborder Anthropoidea: monkeys, apes, and hominids Superfamily Hominoidea Family Hominidae: all hominoids except gibbons Subfamily Ponginae: orangutans Subfamily Homininae: gorillas, chimps, Homo and hominin ancestors 100% % genetic similarity 96% with humans 95% 98% 84% 58% 91% Prothero, 2007 Tarsiers, a primitive Primate (Prosimian) from Southeast Asia. Tarsier sanctuary, Philippines A Galago or bush baby, a primitive Primate (Prosimian) from Africa. A Slow Loris, a primitive Primate (Prosimian) from Southeast Asia. Check out the fingers. Lemurs, primitive Primates (Prosimians) from Madagascar. Monkeys, such as baboons, have tails and are not hominoids. Proconsul, the oldest hominoid, 18 MY Hominoids The Orangutan, a Great Ape from Southeast Asia. Gorillas, Great Apes from Africa. Chimpanzees, Great I’m cool Apes from Africa. Neoteny in Human Evolution. Humans resemble baby apes more than adult apes. Humans are said to be paedomorphic. Chimp skull on the left, human skull on the right Chimp Homo sapiens Consequences of Neoteny • Large brain and cranium • Small jaws and teeth with small face • Retention of juvenile growth patterns • Long juvenile period = extended learning • Retardation of onset of puberty • Longer life span • Naked skin Next: The Hominid Fossil Record.