Transcript Beginning of Life

Beginning of Life
Composition of early atmosphere
Methane, ammonia, hydrogen; no oxygen; no life
Miller/Urey Experiment
Sent electrical sparks through a mixture of gases present in early atmosphere
Created amino acids and sugars-molecules needed for life
Evolution of Life
Evolution of life forms
Pre-cells- molecules organized and surrounded by fats;
molecules pass through fatty membrane
First living cells-Bacteria
Pre-cells take in energy and reproduce
Staphylococcus
Bacteria
Evolution of Life
Heterotrophs
Need energy from outside source
Autotrophs
Chlorophyll; use sun’s energy in
photosynthesis
Eukaryotes Evolve
Oxygen increases in atmosphere;
complex organisms evolve
Algae
Hallucigenia
Ozone Layer Forms
•Lightning converts
O2 to O3
(15 miles above
us)
•Blocks UV light
•Explosion of life
Classification for Humans
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Primates
Family: Pongidae (Great Apes)
Genus: Homo
Species: Sapiens
Homo sapian
The Primate Family Tree
2 Suborders of Primates
Prosimians : “Before monkeys”
Tree Dwelling Primates
Lemurs & Tarsiers
Retain claws, long snout
Found in Madagascar
Tarsier
Lemur
The Primate Family Tree
2 Suborders of Primates
Anthropoids
New World Monkeys (Capuchins, Howler’s)
Old World Monkeys (Macaques)
Humans & Apes (Gorillas, Orangutans)
Trends in Primate Evolution
Dexterity of Hands Opposable thumb for
grasping
Upright Posture  Keeps hands free; plant
harvesting
Vision  Stereoscopic; allows for Depth
perception; food ID
Brain -> Large Brain; Used to obtain food; get
mates
Infant Care Large investment = greater success
Teeth  Multiple Teeth types
Appearance of Homo Sapiens
Humans and Chimpanzee lineages split 6 million years ago
Proconsul Fossil- 18mya-6mya
Proconsul- 18mya-6mya
Australopithecus Afarensis “Lucy”
3-4.5 million years ago
A. afarensis walked on 2 feet (bipedalism)
Small Brain (like a chimp)
Likely vegetarians
More than 1 species of Australopithecines found.
Most species die out about 1-2 million years ago
Homo habilis
1.
2.
3.
4.
2 million years ago
Slightly Larger Brain. Some speech
Simple Tools
Ate plants and butchered Animals
Homo erectus (upright)
1.
2.
3.
4.
5.
1 million years ago
complex tools (hand ax)
Large brain (abstract thought; self
consciousness)
Spreads around the world
Uses fire
Neanderthals (230,000-29,000
years ago)
•Early group of Homo sapiens?
•Found in Middle east, Africa, Asia
•Social Hunters (cooperative groups of 30-40)
•Stone Tools (points, borers)
•Cared for sick, wounded, and dead
•Capable of language
Homo sapians
Early modern humans called Cro-Magnons
• 200,000 years ago to present
• Hey, that’s me!
Other Hominid Fossils
Ar. ramadus
A. boisei
A. robustus
Characteristics of Humans
•Bipedalism Walking on 2 feet
•Shorter toes for standing upright
•Enlarged Brain devoted toward complex
speech
•Smaller Pelvis than other hominids
How and When did our species
supplant H. Erectus?
Multiregional v. Single Origin Theory
Comparisons Among Hominids
Hominid Pelvis
Shallow and rounded
Femurs tilt inward
Body weigh transferred down through knees
Bipedalism
Hominid Spine
Curved like an “S”
Thoracic cage flattened
Transmits weight to the legs
Balanced center of gravity
Hominid Brain
Enlarged
Areas devoted to complex speech and
communication