tracking human evolution: where do we fit on the tree of...
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Tracking Human Evolution:Where Do We Fit on the
Tree of Life?
Geology 230
Fossils and Evolution
Phylogenetic Classification of Humans
Life on EarthEukaryota
AnimaliaBilateria
DeuterostomiaChordata
CraniataVertebrata
GnathostomataOsteichthyes
SarcopterygiiTetrapoda
Phylogenetic Classification of Humans
ReptiliomorphaAmniota
SynapsidaTherapsida
MammaliaEutheria
PrimatesAnthropoidea
HominidaeHomo
H. sapiens
Tree of Life Web Project
Root of the Tree, Life on Earth: http://tolweb.org/Life_on_Earth/1
http://tolweb.org/tree/phylogeny.html
Eukaryoteshttp://tolweb.org/Eukaryotes/3
Animals, Metazoahttp://tolweb.org/Animals/2374
Chordata: dorsal nerve cordhttp://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: skullhttp://tolweb.org/Craniata/14826
Vertebrata: vertebraehttp://tolweb.org/Vertebrata/14829
A living jawless fish, the lamprey
Gnathostomata: jawed vertebrateshttp://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
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 roseafrom 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 legshttp://tolweb.org/Terrestrial_Vertebrates/14952
Tetrapods: Acanthostega andIchthyostega, Devonian of Greenland.
Lobe-Fin Fish or Tetrapods?
Skull roof of
the Late
Devonian
Ichthyostega
Acanthostegausing 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
Reptiliomorphahttp://tolweb.org/Terrestrial_Vertebrates/14952
Crocodiles
hatching from
their amniote
eggs
Pennsylvanian
anapsid or
stem reptile
Amniote Family Tree
Prothero, 2007
Synapsid Skull: one opening behind the orbit (eye)
Diapsid Skull: two openings behind the orbit (eye)
Permian Synapsids, Germany
Triassic synapsid reptiles: Therapsids or
mammal-like reptiles
Therapsida, Mammals and extinct relatives http://tolweb.org/Therapsida/14973
BiarmosuchiaEotitanosuchiaDinocephaliaAnomodontiaTheriodontia
GorgonopsiaTherocephaliaCynodontia
DiviniidaeMammaliaProcynosuchidaeGalesauridaeThrinaxodontidaeCynognathidaegomphodontsChiniquodontidaeProbainognathidaeTritheledontidae (Ictidosauria)
A Gallery of
Therapsids
Carl Buell
From Synapsids to Mammals, a well documented transition series
Prothero, 2007
Prothero, 2007
Yanoconodon, Lower Cretaceous of China
Yanoconodon, Lower Cretaceous of China, retains ear bones attached to lower jaw
Morganucodon
Yanoconodon
Class Mammalia - Late Triassic to RecentSuperorder Tricodonta - Late Triassic to Late
CretaceousSuperorder Multituberculata - Late Jurassic to
Early OligoceneSuperorder Monotremata - Early Cretaceous
to RecentSuperorder Metatheria (Marsupials) - Late
Cretaceous to RecentSuperorder Eutheria (Placentals) - Late
Cretaceous to Recent
Evolution of Mammalian Superorders
Tricodonts U
Eutheria
(Placentals)
Metatheria
(Marsupials)
Live Birth
Mammary Glands?.
.
Multituberculates U
Monotremes
..
Extinct: U
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
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’sOrder 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
98%
96%
95%
91%
84%
58%
100%% genetic similarity with humans
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.
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 Apes from Africa.
I’m cool
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