2. Darwin anD Human Evolution
Lamarck posed the
hypothesis about our
relation to apes before
Darwin
Darwin published
“Descent of Man” in
1871
Caused criticism of his
theory, but already the
basic ides of evolution
had taken hold in the
scientific community.
3. Human Evolution intro
Human 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.
Oneof 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.
Humansare 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
“pygmy chimpanzees”) and gorillas-- shareacommon ancestor that lived
between 8 and 6 million yearsago.
4.
5. PrimatEs
•A primate is a mammal
of the order Primates.
• In taxonomy, primates
include two distinct
lineages, strepsirrhines
and haplorhines.
•Primates 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. Origins estimated back to 65 Million Years Ago .
Oldest fossil only goes back 45 Million Years Ago .
Insect eating nocturnal mammal.
Derived traits for life in trees in the tropics.
Grasping hands and feet.
Separate big toe / thumb.
Sensitive Skin ridges on hands and feet.
Large brains – eye hand coordination- brachiating.
Short jaws.
Forward looking eyes – close together, stereo vision.
Flat nails – not claws.
Long parental care with learned behaviors.
Single births.
Fully opposable thumb.
wHat’s nEw in PrimatEs
7. PrimatE grouPs
PROSIMIANS
Include Lemurs, Tarsiers.
Probably more similar to origin arboreal ancestral
primates
ANTHROPOIDS
Include Monkeys, Apes and Humans.
Split from the Prosimians about 45 Million Years
Ago
8. antHroPoiDs
Include the Monkeys and the Hominoids
Monkeys evolved in two areas ,split about 35 million
years ago
New World monkeys (older),
all arboreal
have prehensile tail, nostrils open to the sides
Squirrel and capuchin monkeys
Old World monkeys
both arboreal and ground dwellers
Lack prehensile tail, nostrils open downwards
Rhesus monkey, baboons, macaques
9. Hominoids
IncludeGreat Apesand Humans
Apes: Gibbons, Orangutan, Gorillas, Chimpanzee/ Bonobo
Split from monkeysabout 20-25MYA
Larger brain sizeto body sizeratiosthan other primates
Moreflexiblebehavior (lessinstinct, morelearned behaviors)
Mostly larger than monkeys(except gibbons)
Havelong arms, short legsand no tail.
Gibbonsand orangutansprimarily arboreal
Gorillas, Chimpsand Humans
Social behavior
Primarily terrestrial
Chimpsmoreclosely related to humansthan gorillas.
12. Hominines (Hominids)
All species believed to be more closely related to human than
chimpanzees
Humans and our direct ancestors, since the split from chimps.
Major groups:
Australopithecines
Paranthropsus
Homo genus
Chimps are not ancestral species !! We shared a common ancestor.
Not a direct line to us !! A radiating lineage. Several hominids species
co-existed.
Gorillas, 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:
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.
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.
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.
Other extant hominidshave2n=48.
Hominids(at least humans) have46.
15.
16. Hominid Life on groUnd:
Bipedalism, upright walking
Jaw shape -smaller with specialized teeth with an omnivorousdiet.
Pronounced chin.
larger brain size, increased cerebrum, by paedogenesis
Reduced sizedifferencebetween sexes
tool use, language, social behavior
Extended parent caretime- longer juvenileperiod
Morelearning
Reduced senseof smell
Increased sizeof brain for vision and co-ordination with muscles
Eyesarelarger and directed forward
20. auStralopithecuS
First “humans”: Australopithecus,
about 4.4Million years ago
Walked fully upright with
humanlike teeth and hands.
Fossil evidence of hip,
hands.
Skull, capacity about 1/3
modern human size.
lasted 3 Million Years.
All fossils from Eastern and
Southern Africa
21. homo
ergaSter
Less sexual dimorphism, more pair
bonding
Larger brain
Slender legs, distance walking
Short straight fingers. No longer climbing
trees
Smaller teeth, foods more prepared less
hard chewing
More advanced tools
More habitats
1.9 - 1.6 Million Years Ago
22. homo erectuS
Homo erectus was the first to migrate out of Africa into
Europe and Asia.
Java man and Peking man are Homo erectus.
H. erectus 1.8 million years ago - 300,000 years ago.
gave rise to larger populations, had to continually
expand to find food, hunt farther out.
23. homo heidelbergenSiS
Descended from H. ergaster in africa, spread out.
Northern populations in Europe under ice age
conditions became The Neanderthals 200,000 -40,000
years ago in Europe
Reaming population in Africa adapted to drought
conditions, became homo sapiens, spread out to rest of
world.
24. homo
neanderthalenSiS
The Neanderthals
200,000 -40,000 years ago in Europe
Brain as large or larger than present
day humans
Buried their dead
Made hunting tools from stone and
wood
Carnivorous
25. Homo sapiens
Two models for the origins of
anatomically modern Humans
Multi regional model has
interbreeding among the different
H. erectus groups and a common
origin for Homo sapiens on the
different continents.
26. Homo forensic
Discovered in 2003
Lived until as recently as 18,000 years
ago
Very small- Island effect
Pygmy elephants
Descent from larger H. erectus