2. Darwin anD Human Evolution
ïLamarck posed the
hypothesis about our
relation to apes before
Darwin
ïDarwin published
âDescent of Manâ in
1871
ïCaused criticism of his
theory, but already the
basic ides of evolution
had taken hold in the
scientific community.
3. Human Evolution intro
ïHuman evolution isthelengthy processof changeby which people
originated from apelikeancestors. Scientific evidenceshowsthat the
physical and behavioral traitsshared by all peopleoriginated from apelike
ancestorsand evolved over aperiod of approximately six million years.
ïOneof theearliest defining human traits, bipedalism -- theability to walk
on two legs-- evolved over 4 million yearsago. Other important human
characteristics-- such asalargeand complex brain, theability to makeand
usetools, and thecapacity for language-- developed morerecently. Many
advanced traits-- including complex symbolic expression, art, and elaborate
cultural diversity -- emerged mainly during thepast 100,000 years.
ïHumansare primates. Physical and genetic similaritiesshow that the
modern human species, Ho mo sapiens, hasavery closerelationship to
another group of primatespecies, theapes. Humansand thegreat apes
(largeapes) of Africa-- chimpanzees(including bonobos, or so-called
âpygmy chimpanzeesâ) and gorillas-- shareacommon ancestor that lived
between 8 and 6 million yearsago.
4.
5. PrimatEs
âąA primate is a mammal
of the order Primates.
âą In taxonomy, primates
include two distinct
lineages, strepsirrhines
and haplorhines.
âąPrimates arose from
ancestors that lived in
the trees of tropical
forests; many primate
characteristics represent
adaptations to life in
this challenging three-
dimensional
environment. Most
primate species remain
at least partly arborcal.
6. ï Origins estimated back to 65 Million Years Ago .
ï Oldest fossil only goes back 45 Million Years Ago .
ï Insect eating nocturnal mammal.
ï Derived traits for life in trees in the tropics.
ï Grasping hands and feet.
ï Separate big toe / thumb.
ï Sensitive Skin ridges on hands and feet.
ï Large brains â eye hand coordination- brachiating.
ï Short jaws.
ï Forward looking eyes â close together, stereo vision.
ï Flat nails â not claws.
ï Long parental care with learned behaviors.
ï Single births.
ï Fully opposable thumb.
wHatâs nEw in PrimatEs
7. PrimatE grouPs
ïPROSIMIANS
ïInclude Lemurs, Tarsiers.
ïProbably more similar to origin arboreal ancestral
primates
ïANTHROPOIDS
ïInclude Monkeys, Apes and Humans.
ïSplit from the Prosimians about 45 Million Years
Ago
8. antHroPoiDs
ïInclude the Monkeys and the Hominoids
ïMonkeys evolved in two areas ,split about 35 million
years ago
ï New World monkeys (older),
ï all arboreal
ï have prehensile tail, nostrils open to the sides
ï Squirrel and capuchin monkeys
ï Old World monkeys
ï both arboreal and ground dwellers
ï Lack prehensile tail, nostrils open downwards
ï Rhesus monkey, baboons, macaques
9. Hominoids
ïIncludeGreat Apesand Humans
ïApes: Gibbons, Orangutan, Gorillas, Chimpanzee/ Bonobo
ïSplit from monkeysabout 20-25MYA
ïLarger brain sizeto body sizeratiosthan other primates
ïMoreflexiblebehavior (lessinstinct, morelearned behaviors)
ïMostly larger than monkeys(except gibbons)
ïHavelong arms, short legsand no tail.
ïGibbonsand orangutansprimarily arboreal
ïGorillas, Chimpsand Humans
ïSocial behavior
ïPrimarily terrestrial
ïChimpsmoreclosely related to humansthan gorillas.
12. Hominines (Hominids)
ïAll species believed to be more closely related to human than
chimpanzees
ïHumans and our direct ancestors, since the split from chimps.
ïMajor groups:
ï Australopithecines
ï Paranthropsus
ï Homo genus
ïChimps are not ancestral species !! We shared a common ancestor.
ïNot a direct line to us !! A radiating lineage. Several hominids species
co-existed.
ïGorillas, chimps and hominids split about 6-8 MYA. At a generous
25 year generation time: 320,000 generations ago with strong natural
selection
14. CHromosome aBnormaLiTY:
ï A chromosome abnormality or mutation isamissing, extra, or irregular portion
of chromosomal DNA . It can befrom an atypical number of chromosomesor a
structural abnormality in oneor morechromosomes.Â
ï Chromosome mutation wasformerly used in astrict senseto mean achangein a
chromosomal segment, involving morethan onegene. A karyotype refersto afull
set of chromosomesfrom an individual that can becompared to a"normal"
karyotypefor the speciesviagenetic testing. A chromosomeabnormality may be
detected or confirmed in thismanner.
ï Chromosomeabnormalitiesusually occur when thereisan error in thecell
division following meiosisor mitosis. Therearemany typesof chromosome
abnormalities. They can beorganized into two basic groups, numerical and
structural anomalies.
ï Other extant hominidshave2n=48.
ï Hominids(at least humans) have46.
15.
16. Hominid Life on groUnd:
ïBipedalism, upright walking
ïJaw shape -smaller with specialized teeth with an omnivorousdiet.
Pronounced chin.
ïlarger brain size, increased cerebrum, by paedogenesis
ïReduced sizedifferencebetween sexes
ïtool use, language, social behavior
ïExtended parent caretime- longer juvenileperiod
ïMorelearning
ïReduced senseof smell
ïIncreased sizeof brain for vision and co-ordination with muscles
ïEyesarelarger and directed forward
20. auStralopithecuS
First âhumansâ: Australopithecus,
about 4.4Million years ago
ï Walked fully upright with
humanlike teeth and hands.
ï Fossil evidence of hip,
hands.
ï Skull, capacity about 1/3
modern human size.
ï lasted 3 Million Years.
ï All fossils from Eastern and
Southern Africa
21. homo
ergaSter
ïLess sexual dimorphism, more pair
bonding
ïLarger brain
ïSlender legs, distance walking
ïShort straight fingers. No longer climbing
trees
ïSmaller teeth, foods more prepared less
hard chewing
ïMore advanced tools
ïMore habitats
ï1.9 - 1.6 Million Years Ago
22. homo erectuS
ïHomo erectus was the first to migrate out of Africa into
Europe and Asia.
ï Java man and Peking man are Homo erectus.
ï H. erectus 1.8 million years ago - 300,000 years ago.
ï gave rise to larger populations, had to continually
expand to find food, hunt farther out.
23. homo heidelbergenSiS
ïDescended from H. ergaster in africa, spread out.
ïNorthern populations in Europe under ice age
conditions became The Neanderthals 200,000 -40,000
years ago in Europe
ïReaming population in Africa adapted to drought
conditions, became homo sapiens, spread out to rest of
world.
24. homo
neanderthalenSiS
ï The Neanderthals
ï 200,000 -40,000 years ago in Europe
ï Brain as large or larger than present
day humans
ï Buried their dead
ï Made hunting tools from stone and
wood
ï Carnivorous
25. Homo sapiens
ïTwo models for the origins of
anatomically modern Humans
ïMulti regional model has
interbreeding among the different
H. erectus groups and a common
origin for Homo sapiens on the
different continents.
26. Homo forensic
ïDiscovered in 2003
ïLived until as recently as 18,000 years
ago
ïVery small- Island effect
ïPygmy elephants
ïDescent from larger H. erectus