1. Hominid Evolution & Classification
Chapter 16

2. Hominid Skulls Subject A = Chimpanzee
Subjects J-L = Neanderthal (70,000 to 45,000 years ago)
Subject M = Cro Magnon (30,000 years ago)
Subject N = Modern Man

3. Human Classification
Domain: EUKARYA Kingdom: ANIMALIA Phyla: CHORDATA Subphyla: VERTEBRATA Class: MAMMALIA Subclass: EUTHERIA Order: PRIMATA Suborder: ARTHROPOIDEA Family: HOMINIDAE Genus: HOMO Species: SAPIENS
Humans are members of an order of mammals: primates.
Primates first appeared about 65 million years ago.
The first primates lived in trees, and we have inherited some of their characteristics.

4. Characteristics of Primates
Highly diverse group with the following general features in common
Manual dexterity: an opposable first digit
Senses:
Binocular vision (eyes on the front of the face allowing for overlapping fields of vision)
Color vision (if diurnal) and black/white vision (if nocturnal)
More brain power devoted to vision than smell
Locomotion: flexible bodies that allow for easy movement
Complex brain and behaviors: problem-solving, socializing, and communicating
Reproductive rate: fewer offspring; single births

5. Other Primates Great Apes Orangutans Chimpanzees Gorillas Humans
Female orangutan
Male orangutan

6. Suborder: Arthropoidea
Domain: EUKARYA
Kingdom: ANIMALIA
Phyla: CHORDATA
Subphyla: VERTEBRATA
Class: MAMMALIA
Subclass: EUTHERIA
Order: PRIMATA
Suborder: ARTHROPOIDEA
Family: HOMINIDAE
Genus: HOMO
Species: SAPIENS
Arthropodoidea: all non-monkey primates
Genetically speaking, humans are most closely related to apes.
These primates lack tails and have forelimbs longer than their hind limbs

7. Chromosome Analysis
We share more than 97% of our genes with chimpanzees.
Our behavior also has some similarities.
Chimpanzees make and use simple tools.
They seem to have a sense of self.

8. Primate Evolution Cladogram
Domain: EUKARYA Kingdom: ANIMALIA Phyla: CHORDATA Subphyla: VERTEBRATA Class: MAMMALIA Subclass: EUTHERIA Order: PRIMATA Suborder: ARTHROPOIDEA Family: HOMINIDAE Genus: HOMO Species: SAPIENS

9. Hominid Evolution
The human branch of the primate tree is only a few million years old. Apes and hominids diverged from a common ape-like ancestor between 8 and 5 million years ago.

10. Hominid Characteristics
Big brain with more complexity in areas responsible for reasoning
Thinner face with smaller teeth
Long thumbs and flexible wrists
Bipedal (upright walkers):
Shorter arms
Restructured pelvic and foot bones
Hole for spinal cord at the base of the skeleton rather than the back

11. Genus: Homo Continued structural changes: Significant advances:
Domain: EUKARYA
Kingdom: ANIMALIA
Phyla: CHORDATA
Subphyla: VERTEBRATA
Class: MAMMALIA
Subclass: EUTHERIA
Order: PRIMATA
Suborder: ARTHROPOIDEA
Family: HOMINIDAE
Genus: HOMO
Species: SAPIENS
Continued structural changes:
Larger brains
Thinner faces
Smaller teeth
Significant advances:
Used tools
Hunted and gathered food
Used fire
Built shelters
Developed culture and communication

12. 200,000 years ago, many species of the Homo genus were present.
Species: sapiens
Binomial classification: use the genus and species names to refer to an organism
Homo sapiens (modern human) appeared in Ethiopia about 195,000 years ago.
200,000 years ago, many species of the Homo genus were present.

13. Out of Africa Hypothesis (1988)
200,000 years ago, many species of the Homo genus were present.
30,000 years ago, only homo sapiens remained.
WHAT HAPPENED TO THE OTHER SPECIES?
1988 Out of Africa Hypothesis: modern humans evolved in Africa and then migrated to other parts of the world.

14. Out of Africa Hypothesis (1988)
In the 1990s, scientists learned about mitochondrial DNA.
Mitochondrial DNA is a smaller fragment of DNA found in the mitochondria of eukaryotes. Only 37 genes are located on human mitochondrial DNA. All of these genes are related to mitochondria function.
Mitochondrial DNA is ONLY inherited from mothers as sperm mitochondria are destroyed by the egg after fertilization.
Mitochondrial DNA changes very little over time. It takes many years for mutations to occur.
Remember molecular clocks? The more mutations…the longer the species has existed.
Scientists have studied mitochondrial DNA from humans all over the earth. They found that people in Ethiopia have the most mutations in their mitochondrial DNA.
Therefore, humans likely originated in Ethiopia from a “Mitochondrial Eve.”

15. Migration of Descendants of Mitochondrial Eve

16. Final Overview of Family Hominidae Evolution?
Australopithecus robustus
Homo ergaster
Australopithecus africanus
Homo sapiens
Australopithecus afarensis
Homo neanderthalensis
Millions of years ago
Homo erectus
Australopithecus anamensis
Australopithecus boisei
Homo habilis
Ardipithecus ramidus
Ardipithecus ramidus kadabba
Orrorin tugenesis