Transcript Humans Have a Relatively Short History

Humans Have a Relatively Short History
Fossil Records
Indicate that modern humans have a relatively
recent history
Began in Africa
In a short time, humans have become the
most numerous and widespread large animal
on Earth
Hominines – the hominoids in the lineage that led
to humans
Homo Sapien (modern human) – only species in
existence today
• Many hominines lived in the past
• Earliest hominines may have lived 6 to 7 million
years ago
Two important developments in the evolution
of hominids:
1. Upright Posture (leading to 2 – legged walking)
2. Brain enlargement
Sahelanthropus
• 7million year old – Found in Central Africa
• A million years older than any other known hominine
• Brain about the size of a modern chimp
• Short broad face was more human
• Still debate whether this fossil represents a hominine
Walking Upright
Bipedalism – walking on two feet
• Australopithecus Afarensis – oldest evidence of
upright posture and walking on two feet.
• Walked upright 4 million years ago
• Lucy – a female Australopithecus Afarensis
• 3 ½ feet tall, head about the size of a softball
• Australopithecus Afarensis species were extinct by
about 1.2 million years ago
Australopithecus Afarensis
Dikika Baby
Lucy
Later species overlapped in time with early
species of the genus homo.
Walking upright evolved before enlarged brain
Enlarged Brain
• First enlarged brain relative to body size
appeared 2.5 million years ago
• Many skulls have been found between the size of
Australopithecus and H. Sapiens
• Simple stone tools were found with these species
• Species name Homo habilis (Handy Man)
• Used skilled hands and big brains to invent
tools
• Enhanced the ability to hunt, gather food, and
scavenge for food
Oblongata
Language
Estimates range from about two million years
ago, during the time of Homo habilis (Handy
Man), to as recently as forty thousand (40,000)
years ago, during the time of Cro-Magnon man,
Homo habilis - Handy Man
• Opposable Thumb – thumb could touch the tips of
the fingers, enabling the
grasping of objects and the
use of tools
Paranthropus
• 3 recent species grouped
together which grew into the
size of well-fed NFL
Linebackers placed in their
own genus
• Diets include course and
fibrous plant foods like
modern gorillas
Homo erectus – first hominine fossil observed in a
continent other than Africa
• H. Erectus was taller and had a larger brain that
H. habilis
• During their 1.5 million years of existence they
grew to about the size of modern humans
• Oldest H. erectus fossils found outside of Africa
are 1.8 million years ago in the country of
Georgia, near Russia
Early Homo Sapiens coexisted with another
hominid species; Homo Neanderthalensis
• Neanderthals
• Lived in area of Europe
• Made tools from stone and wood
• Fossil records indicate that
Neanderthals
• Did NOT give rise to modern Homo
Sapien
• Became extinct 30,000 years ago
There are many hypothesis for the origin of fully
modern humans
Fossil records now suggest that ancestors
originated in Africa
Homo Sapien fossils that look like today’s
modern Homo Sapien are about 195,000 years
old and it was discovered in Ethiopia
Also discovered in Ethiopia
Also supported by DNA
Molecular biologist analyzed mitochondrial DNA
from living humans around the world
determined when they last shared a common
ancestor.
The estimated date for that African common
ancestor is between 200,000 and 150,000 years
ago.
More recent DNA data suggest that a small
subset of those African ancestors left
northeastern Africa between 65,000 and 50,000
years ago to colonize the world.
Data supports Theory
New Findings
• In 2003 scientist discovered a fossilized skeleton
of a previously unknown hominine species
• Found on the island of Flores, Indonesia
• Called Flores Man (Homo Floresiensis)
• Only 18000 years old
• Smaller skull and shorter than modern Homo Sapiens
• Previously thought no other hominine existed while
Homo Sapiens had spread over most of the Earth