An overview of human evolutionary history and taxonomy.

1. FROM FIRST PRIMATES
TO
FIRST BIPEDS
A non-linear and intricate process… don’t be fooled by the image!

2. EVOLUTIONARY
RELATIONSHIPS
 Scientists use a system of
classification known as TAXONOMY
to organize all living things into
categories based on similarities and
differences.
 The classification scheme starts with
very general similarities
 Taxonomic levels become more and
more specific for inclusion
 The smallest classification level
contains only closely related
organisms.
KINGDOM
PHYLUM
CLASS
ORDER
FAMILY
GENUS
SPECIES

3. HUMAN TAXONOMY
KINGDO
M
PHYLUM
CLASS
ORDER
FAMILY
GENUS
SPECIES
ANIMALS
CORDATES
MAMMALS
PRIMATES
HOMINIDS
HOMO
HOMO
SAPIENS
Organisms able to move on their own
Animals with a backbone
Cordates with fur or hair and milk glands
Mammals with collar bones and grasping fingers
Primates with relatively flat faces and three-
dimensional vision
Hominids with upright posture an large brains
Members of the genus Homo with a with a
heightened forehead and thin skull bones

4. EVOLUTION ON A GEOLOGIC TIMESCALE
 Visual, anatomical, and genetic change (evolution) tends
to occur in a pattern of PUNCTUALTED EQUILIBRUM
where long periods of stability are punctuated by periods
of rapid change.
 EXAMPLE: dinosaurs roamed the earth for 100 million
years until a meteor crashed into earth and caused a
global cooling effect that lead to their extinction
 Mammals begin to proliferate during the mass extinction
of dinosaurs 65 million years ago (rapid change)
 55 million years ago true primates emerge due to a
warming trend in the enviornment

5. WHAT DEFINES A MAMMAL?
Hair Mammary
glands –
produces milk
Reproductive
system –
long gestation
period
Circulatory
system –
four chambered
heart
Allows for
thermoregulation
Neocortex –
higher function
part of the
Spatial relations
Reasoning
Conscious thought
Language/communication
Sensory perception (feeling and

6. WHAT DEFINES A PRIMATE?
Skeleton Brain Teeth Sensory Organs
Binocular stereoscopic
vision (forward facing, 3D,
color vision)
Opposable thumbs
Prehensile(grasping)
hands and feet
Clavicle (allows for
increased arm mobility)
Reliance on sight and
social behavior
Reduced use of
olfactory senses
Rounded (rather than
sharp) molar cusps

7. TAXONOMY OF PRIMATES
PROSIMIANS ANTHROPOIDS
MONKEYS APES HUMANS
Chimpanzee
OrangutansGorillas
Bonobo
TARSIERSLORESIS
Gibbons
LEMURS

8. PRIMATOLOGY
 A sub-field of Biological/Physical Anthropology that
studies non-human primates
 In the past (fossils) and the present (living animals)
 Primatologists study the behavior and social life of
their subjects by looking at HOMOLOGIES, which
are similarities inherited from a common ancestor

9. BECOMING BIPEDAL
 Walking upright on two legs is unique to humans
Other primates are QUADRAPEDAL (walk on all four limbs)
Or BRANCHIATE (swing from branch to branch) as a means of locomotion
Becoming BIPEDAL required anatomical changes that
took place over a span of more than 50 million years…

10. ANATOMICAL CHANGES
 PELVIS – adjusted iliac crest from a posterior to a
lateral position to allow for upright locomotion
 FORAMEN MAGNUM – the hole at the base of
the skull adjusts to support an upright position to
balance the skull atop the spine
 ARMS – shorter in length for increased movement
 TEETH – overall structure changes to
accommodate varied diet
 BRAIN – becomes larger in capacity

11. HUMAN
ANCESTORY
1. Sahelanthropus Tchadensis (Toumai)
2. Orronin Tugensis
3. Ardipithecus Ramidus
Australopithecines
4. A Anamensis (4.2-3.9 mya)
5. A. Afarensis (3.8-3 mya)
6. A. Africanus (3-2 mya)
7. A. Garhi (2.5 mya)
8. A. Robustus (2-1 mya)
9. A. Boisei (2.6-1.2 mya)
10. A. Sediba (1.9-1.7 mya)
Homo
11. H. Rudolfensis
12. H. Habilis
13. H. Erectus
14. H. Sapiens
14a. Archaic Homo Sapiens
14b. Neandertals
14c. Anatomically Modern Humans (AMH)

12. HUMAN ANCESTORY BREAKDOWN
Homoniod (family)
1. Sahelanthropus Tchadensis (Toumai)
Hominin (subfamily)
2. Orronin Tugensis
3. Ardipithecus Ramidus
Australopithecines (genus)
1.
3.

13. HUMAN ANCESTORY BREAKDOWN
Australopithecines (genus)
4. A Anamensis (4.2-3.9 mya)
5. A. Afarensis (3.8-3 mya)
6. A. Africanus (3-2 mya)
7. A. Garhi (2.5 mya)
8. A. Robustus (2-1 mya)
9. A. Boisei (2.6-1.2 mya)
10. A. Sediba (1.9-1.7 mya)
Homo (genus)
5.
5.
5.
Lucy
Letoli Footprints (LF)
LF

14. HUMAN ANCESTORY BREAKDOWN
Homo (genus)
11. H. Rudolfensis
12. H. Habilis
13. H. Erectus
14. H. Sapiens
14a. Archaic Homo Sapiens
14b. Neandertals
14c. Anatomically Modern Humans (AMH)
12.
14b.

15. REMEMBER…
 Humans are classified on their OWN BRANCH of evolutionary history
 Humans DIVERGED from apes and monkeys however, we all SHARE a common
ancestor
 Evolutionary forces that caused humans to branch from other primates:
MUTATION – random changes in genes that introduce new variation
GENETIC DRIFT – fluctuations in the gene pool that influence survival (i.e
unique or catastrophic events)
GENE FLOW – the introduction of new alleles from nearby populations
NATURAL SELECTION – adaptative change for survival

16. REMEMBER…
 New findings are constantly changing the evolutionary timeline
 Evolutionary relationships are controversial
 Some scholars prefer to “’lump” similarities into an existing species category
 Some scholars prefer to “split” differences into a new species category

17. TIMELINE
REVIEW
65 mya – environment cools, dinosaurs go extinct,
mammals radiate across the globe
55 mya – environment warms, mammals slight demise,
proliferation of primates
6-7mya – first signs of bipedal locomotion
2.6 mya – first signs of tool use and the genus Homo
150,000 ya – emergence of language