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Hominin Evolution - Classification. Aims: Must be able to outline the characteristics used for classification of Hominins. Should be able to outline the main differences between species for the main characteristics. Could be able to apply knowledge of characteristics to group organisms. - PowerPoint PPT Presentation
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Hominin Evolution - Classification
•Aims:
•Must be able to outline the characteristics used
for classification of Hominins.
•Should be able to outline the main differences
between species for the main characteristics.
•Could be able to apply knowledge of
characteristics to group organisms.
Hominin Evolution - Classification
Human evolution is the
physical and cultural
development and change
of our hominin ancestors
to modern humans.
Humans are Mammals:
Humans are Primates:
Homo sapiens = One of approximately 200 living primate species, which together constitute the order Primates.
Homo sapiens have inherited a set ofanatomical and behavioral features thatreflect our evolutionary history.
By studying the characteristicsof present-day primates,we are able to look backat stages in our ownevolutionary development.
Primate Grades
Prosimians New World Monkeys
Apes HominidsOld World Monkeys
Primate Characteristics
• Combination of features that are unique to their group.
• Anatomy is well adapted to an arboreal (tree-dwelling) lifestyle.
• They possess:
• Superior intelligence
• Often complex social behavior
• A highly developed problem solving ability
• Features that distinguish primate species from each other include:
• Tail anatomy
• Skull anatomy, including: Brow ridges
Vision
Nostrils
Snout and lips
• Limb length
• Hand and foot anatomy
Primate Physical Features
Primate Skulls•The skulls of various primate groups:
Borneo Orangutan
Chacma Baboon
Tarsier
Chimpanzee
Spider monkeyRuffed Lemur
• Some primates have a heavy brow ridge while others have little or no apparent brow ridge.
Gorilla Skulls• Gorillas exhibit sexual dimorphism in skull features.
• Female gorilla skulls differ from those of males by having:
Female Male
Very small sagittal crest
Small nuchal crest
Female skull smaller than male
Large sagittal crest
Large nuchal crest
Gorilla Skull FeaturesSagittal crest (attachmentsite for jaw muscles)
Low, small cranial vault
Brow ridge
Heavy malar(cheek bone)
Diastema (gap)
Large incisors
Large canines used as defensive weapons
Large molars forgrinding vegetation
Massive jawwith no chin
Foramen magnumpositioned at rear
Massive zygomatic arch through which jaw muscles pass
Nuchal crest (for the attachment of neck muscles)
Protrudingmuzzle
Primate Tails
•Features that distinguish primate tails:
•Tails present or absent
•A prehensile tail can be used to grip things
•Furred or not furred
•Long or short
Primate Feet and Hands• Hands and feet of various primate groups:
Hand
Foot
Squirrel Monkey
Foot
ChimpanzeeHand
Foot
GibbonHand
FootGorillaHand
FootLorisHand
FootOrangutan
Hand
FootTarsierHand
FootBaboonHand
Primate Feet and Hands
Human hand Human foot Tarsier foot Gorilla footOpposable
thumb
Non-opposable
big toe
Claws on
some fingersNails
Opposable
big toe
•Hands and feet of various primate groups can be distinguished by the following features:
•The presence of claws or nails
•Thumbs or big toes opposable or non-opposable
Primate Limbs
• An important feature that distinguishes certain primates is limb length - the ratio of the length of arms to legs
Arms longer than the legs Legs longer than the arms
Order
Suborder
InfraorderSuperfamil
yFamily
Subfamily
TribeExamples
PRIMATES
Prosimii(prosimian
s)
Plesiadapiformes
(archaic primates)
extinct plesiadapiformes
(Purgatorius)
LemuriformesLemuroidea
Lemuridae
Indriidae
lemurindri
Adapoidea Adapidae extinct adapiformes
Lorisiformes Lorisoidea Lorisdae loris, galago (bush baby)
Tarsiiformes Tarsioidea
Tarsiidae tarsier
Omomyidae
extinct omomyiformes
Anthro-poide
a(simians or
anthropoid
s)
Platyrrhini(New World
simians)
Ceboidea(New World
Monkeys)
Callitrichidae
marmoset, tamarin
Cebidae(true
monkeys)
cebus monkey, spider monkey, howler
monkey, capuchins, owl monkey, sakis
Catarrhini(Old World
Simians)
Cercopithecoidea
(Old World Monkeys)
Cercopithecidae
colobus, langurs, macaque, baboon
Hominoidea(apes and
humans)
Oreopithecidae
extinct Oreopithecus
Hylobatidae
gibbon, siamang
Hominidae
Pongidae orangutan,
Homininae
Gorillini gorillas
Panini chimpanzees
Hominini
humans
Human classification Extinct lineage
Primate Classification – Based on Physical Characteristics
Hominid or Hominin?
Hominid – Group consisting of all modern
and extinct Great Apes (Modern human beings,
chimpanzees, gorillas and orang-utans and all
immediate ancestors).
Hominin – Group consisting of modern
humans, extinct human species and all of our
immediate ancestors.
Classifications Can Change…
•Pre 1980 hominid had the same meaning that
hominin now has…
•Hominid has now been designated a broader
meaning (including Great Apes and their
ancestors).
•Many texts and websites still use the old
naming system – beware!
Modern humans, extinct human species and all immediate
ancestors.
Why Change?
•Over time biological classification
changed due to improved techniques
and better knowledge about the biology
and the evolutionary relationships of
different living things:
•E.g. DNA analysis
Genetic Similarity of Primates• The genetic relationships among the primates have been investigated
using DNA hybridization as well as comparing DNA sequences.
DNA Similarity (%) to Humans
Genetic Similarity of Primates• Human DNA was compared with that of the other primates and
largely confirmed what was suspected from anatomical evidence.
Patterns of relationship among the apes and Old World monkeys based on information from DNA-DNA hybridization:
Human
Pygmy chimpanzee
Common chimpanzee
Gorilla
Orangutan
Gibbons
Old World monkeys
Primate Evolution
Lemurs & lorises Tarsiers
New World monkeys
Old World monkeys Gibbons Orangutans Gorillas Chimpanzees Humans
Present1.8
5
PLEISTOCENE
PLIOCENE
UPPER MIOCENE
MIDDLE MIOCENE
LOWER MIOCENE
10
15
Mill
ions
of y
ears
ago
20
25
30
35
40
45
505560
OL
IGO
CE
NE
EOCENE
PALEOCENE
Adapiformes
Purgatorius
Strepsirhines
May have given rise to the primates, in Africa 60 million years ago (probably tree-dwelling and adapted to gliding between trees)
Omomyiformes
Afrotarsius
Branisella
ProhylobatesMicropithecus?
AegyptopithecusPropliopithecusOligopithecusCatopithecus
AfropithecusProconsul
Dryomorphs
KenyapithecusDryopithecus
After Colin Groves
OuranopithecusSivapithecus
Krishnapithecus
Gigantopithecus
Haplorhines
Split between hominids and chimpanzees
about 8-6 mya
Oldest known anthropoids about 40-30 million years ago
O. tugenensisS. tchadensis
Hominoid Evolution•Classification of the great apes
and humans is difficult.
• In the light of DNA comparisons, one solution is to place orangutans in the subfamily Ponginae and to combine African apes and humans in the subfamily Homininae.
• In addition, a new level ofclassification is created, called tribes:
• Hominini for humans andpre-humans
• Gorillinae for the gorillas
• Panini for the chimpanzees.
Modern Classification - Hominoids
• This modern classification of the hominoids addresses the genetic similarity of gorillas, chimpanzees, and humans.
• Note that under this scheme, the term ‘hominid’ (i.e. a species from the Hominidae) would refer to a ‘great ape’ or human species.
• This scheme is still not widely adopted.
Activity
•Complete the questions on page 371
to 373 In the Biozone book: