1. Looking at Human Evolution

2. Recall the classification system…
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Primates

3. Order: Primates All Primates Fig. 21.02 Lemurs Tarsiers New World
Suborder Prosimii
Suborder Tarsiiformes
Anthropoids (suborder Anthropoidea)
Hominoids
Hylobatidae
Pongidae
Hominidae
New World
monkeys
Old World
monkeys
Lemurs
Tarsiers
Gibbons
Orangutans
Gorillas
Chimpanzees
Humans
Common Ancestor of hominids
Common Ancestor of hominoids (hominids and apes)
Common
Ancestor of anthropoids
Common Ancestor of
All Primates
Fig

4. Prosimians tarsier lemur loris lemur tarsier white face Colubus monkey
lemur
white face Colubus monkey
Prosimians
gorilla
loris

5. Key Primate Traits
Most key primate traits are directly involved or indirectly involved in brachiation (the swinging of limb to limb in trees)
free movement of upper arm in any direction
able to rotate arm bones and turn hand in a semi-circle (also for brachiation)
5 digits with opposable thumb for grasping branches and manipulating food
Eyes in front of face (for 3-D vision)

6. Characteristics of organisms classified in Order Primates:
Strong and sensitive fingers
Opposable thumb
Brains larger proportionally
Binocular (3-D) and color vision
Omnivorous
Usually give birth to 1 offspring at a time (allows for extended care)

7. But at the Family level, humans branch off from other primates
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Primates
Family: Pongidae
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Primates
Family: Hominidae

8. Our branch
We are on the ANTHROPOID branch (monkeys and apes, as opposed to prosimians: lemurs and tarsiers)
Prosimians probably resemble early arboreal primates.

9. The Naked Ape Within the anthropoids, our group is the apes.
Apes include gibbons, orangutans, gorillas, and chimpanzees (two species).
Traits--large brain, long arms and short legs. Capable of brachiation, but only gibbons and orangutans are primarily arboreal.

10. The Hominid-Ape Split Humans split from the ape line between 5 –8 mya
Molecular evidence puts the split between humans and apes at about 5-8 million years ago.

11. Bipedality Original Explanation:
Why did bipedality emerge?
Original Explanation:
This split between hominids and apes is thought to have resulted from the continuing drying trend, changing woodland into open plains. Any ape with a pre-adaptation for surviving in the plains would have an enormous survival advantage, and would be able to pass these traits to its offspring. Problem: many fossil humans have been found in dense woodland or wooded lakeside habitats.

12. Other Explanations
Intrinsic: Walking upright increased the range of vision, freed the hands for gathering, allowed for holding of children while standing.
Heat regulation: Standing upright vastly decreased body heating from the sun, decreasing heat stress. In this model, upright posture would have accompanied loss of body hair and the development of sweating as a means of evaporative cooling.
Problem: there is at least one highly successful group of monkeys — baboons — who made the transition toward savannah lifestyle, without becoming bipedal. Also, the earliest hominids appeared to live in wooded environments much like the ones where chimps live.

13. Some anatomical ways we differ from Pongids:

14. Hand
Foot
Hand
Foot
(a) Lemur (Eulemur mongoz)
(b) Tarsier (Tarsius spectrum)
Hand
Foot
Hand
Foot
(c)
Woolly spider monkey
(Brachyteles arachnoides)
(b) Gorilla (Gorilla gorilla)
Fig

15. So now a brief glimpse into human evolution…

16. Australopithecus afarensis
Age: mya
Bipedal
Small brain
Large, wide teeth
Most complete early hominid
Possible ancestor of all later australopithecines (A. africanus, A. robustus, A. boisei, A. aethiopicus, A. garhi)
art
bones
prints

17. A. afarensis: artist’s renderings

18. A. afarensis: skeleton
ensis/images/afarensis-three-skeletons.jpeg

19. A. afarensis: footprints

20. Paranthropus robustus
Note the large (robust) cheeks, jaw, teeth, etc)

21. Paranthropus robustus
boisei_robustus/other_information/other_information2.shtml
australopithicus/boisei_robustus/other_information/other_information.shtml

22. Homo habilis Age: 2.3 - 1.6 mya Significantly larger brain size
Clear evidence of tool use
Broca’s area (essential for speech) visible in brain cast

23. Homo habilis tools

24. Homo erectus Age: 1.8 - 0.3 mya First to leave Africa
Traveled throughout Africa, Europe, and Asia
Stone and bone tools
May have used fire
art
bones
tools
travel

25. H. erectus: skeleton http://donsmaps.com/erectus.html

26. H. erectus: artist’s renderings

27. H. sapiens neanderthalensis
Age: 250,000-30,000
Coexisted with H. sapiens sapiens
Larger brain and body size
Adapted to cold
Used fire
Buried dead
Cared for wounded and elderly
art
bones
range
tools
culture

28. H. sapiens neanderthalensis: artist’s renderings

29. H. sapiens neanderthalensis: skeleton

30. H. sapiens neanderthalensis: culture
50,000 year old bone flute
(neanderthal or modern human?)
Burial site with flowers

31. Humans are Young
As a species, Homo sapiens is only 300,000-50,000 years old.
In relation to several billion year history of the earth, this is an extremely small amount of time.

32. H. sapiens sapiens Age: 100,000 - present Cave art, sculptures, etc.
Small teeth & jaws
Very high forehead, prominent chin
paint
sculpt
homo_floresiensis_1/images/primary/flores_sapiens.jpg

33. H. sapiens sapiens: painting (Cro Magnon, caves in France)

34. H. sapiens sapiens: sculpture
22,000 B.C.E.--ivory
22, ,000 B.C.E.--stone
12,000 B.C.E.--reindeer antler

35. Cultural Evolution is by far the major force at work in changing humanity.
Agriculuture began only about 11,000 years ago.
Modern science began only about 500 years ago.
The industrial revolution was 200 years ago.

36. One final note…humans have evolved through
variation, mutation, and natural selection like all other
species.And we continue to evolve today.
Yet, keep in mind that evolution occurs in a branching fashion,
With some paths diverging and evolving differently
depending on environmental conditions, the variations that
arose etc. Some paths lead to “dead ends” and those human
species have gone extinct.
Remember the branching tree and not a linear progression.

37. Hominid Family Tree H. sapiens sapiens H. sapiens neanderthalensis
H. sapiens (archaic)
H. erectus
H. ergaster
Homo habilis
A. robustus
A. boisei
A. aethiopicus
A. africanus
A. garhi
A. afarensis
Kenyanthropus platyops
Australopithecus anamensis
Ardipithecus ramidus

38. The End…(but not really!)