human evolution presentation by biochemistry students

1. HUMAN
EVOLUTION
STAGES OF HUMAN
EVOLUTION
GROUP TWO

2. HUMAN EVOLUTION
• Evolution is a slow and gradual process
of change in the heritable characteristics
of organisms throughout generations. We
are now the only living members of what
many zoologists refer to as the human
tribe, hominins, but there is abundant
fossil evidence to indicate that we were
preceded for millions of years by other
hominins
• Some of the factors that affect human
evolution are natural selection, genetic
drift, migration, climate change, etc.
• There are seven major stages of human
evolution. They are Ardipithecus ramidus,
Australopithecus afarensis, Homo habilis,
Homo erectus, Homo heidelbergensis,
Homo neanderthals, and Homo sapiens.

3. ARDIPITHECUS RAMIDUS
• They lived 4.4 million years ago in Ethiopia
• They were the most ape-like with a brain
size of 300-350cm3
• They were the hairiest among human
ancestors and lived in woodlands
• Facial anatomy did not exhibit
aggressiveness because they had smaller
canines and incisors
• They exhibit sexual dimorphism in height
but lack sexual dimorphism in terms of their
canine tooth
• They were prognathic meaning the lower
teeth rolled over the upper teeth
• They had opposable digits for gripping
trees(arboreality)

4. AUSTRALOPITHECUS
AFARENSIS
❖ They existed 3.2 million years ago
❖ They lived in the Pliocene of east Africa
❖ They lived in the woodlands with
patches of grassland and exhibited
bipedalism
❖ They had a brain size of 450cm3 and
better vision to spot predators
❖ Had smaller canines but larger than
homo sapiens
❖ Their extinction was due to the severity
of drought

5. • They existed about 2.3 million years
ago and lived in a grassland
environment
• They had a slightly rounded skull with
a brain size of about 610cm3 , the
increase in brain size aided them to
make their own tools(stone tools) to
fight predators
• They were the first to make fire
• The hole for spinal cord was in the skull
base showing they walked on two legs
• They had curved finger bones and
relatively short legs
• They had smaller canines with larger
incisors
HOMO HABILIS

6. ❖ They lived around 250000 years ago and
inhabited Africa, Europe, Australia and some
parts of Asia especially around rivers
❖ They had larger brains of about 550-
1250cm3 as compared to Homo Habilis and
developed more improved tools
❖ They had a large and thick jaw with no chin
❖ They were carnivorous and could cook
their own food
❖ They were more populated than homo
habilis
❖ Their extinction was due to their laziness
HOMO ERECTUS

7. ❑ In 1901 the jawbone (maeur) of what
is believed to be an archaic species
was discovered in Heidelberg, a town in
Germany and the species was later
named Homo heidelbergensis
❑ They existed around 600000 years
ago and lived in temperate regions
(cold environments)
❑ They had a short and wide body
stature, which helped them to conserve
heat
❑ They had a brain size of about 1220-
1300 cm3 and improved upon their
tools for hunting
❑ They lived In social groups and built
their own shelter and also buried their
dead.
•
•HOMO HEIDELBERGENSIS.

8. Heidelbergensis continued;
❑ They exhibited sexual dimorphism
❑ They had thick and broad jaws with small
teeth and depended so much on meat
❑ It was deduced by scientist that members
of the homo heidelbergensis buried their
dead members. This was because many of
their fossils were discovered at a particular
place together in Spain.
❑ Some of their fossils were discovered
with the fossils of predators and this
indicates that they fought predators, and
some were killed by predators.

9. HOMO NEANDERTHALS
• They existed around 400000 years
ago and were found to inhabit cold
steep environments (ice age period)
• They had short and wide body stature
which aided in heat conservation
• They had a very wide nose( made air
warm)
• They had powerful arms for killing
strong animals
• They had a long low skull
• Were also believed to have the largest
brain size (1500-1700cm3)
•

10. ❑ Homo sapiens are believed to still be in
existence till now, they have a large brain
size(of about 1350cm3 ) but not larger than
H. Neanderthals
❑ They are the most widespread species
which inhabit temperate, tropical, tundra,
terrestrial, savanna and desert regions
❑ They have rounded brain cases to
accommodate the large brain size
❑ They have a small face protracted under the
frontal tori
❑ They have less hair
HOMO SAPIENS

11. THANK YOU