ch 14 Flashcards
The first primates evolved about how long ago
60 million years ago from small, insect-eating mammals that lived in trees.
Primates have what body features
grasping fingers and toes, as well as binocular vision.
The first primates were
prosimians.
Monkeys evolved from who, when, and have what new features
prosimian ancestors about 36 million years ago.
The development of color vision and opposable thumbs in these diurnal primates is associated with a more developed brain.
Human ancestors diverged from the evolutionary line leading to who about how long ago
gorillas and chimpanzees about 4 million years ago. DNA similarities suggest that humans have a closer evolutionary relationship to chimpanzees than to other primate species.
The earliest known direct ancestors of humans belong to the genus what and exhibit what evolutionary milestones
Australopithecus. Australopithecines, which were hominids (belonging to the human line), exhibited two characteristics that were evolutionary milestones: they were bipedal and they had large brains relative to body weight.
The first australopithecine fossil, found in 1924, is thought to be how old
2.8 million years old. Since then, many australopithecine fossils have been found, some of which are estimated to be 3.9 million years old.
Because of an incomplete fossil record, scientists differ in their interpretations of what
how australopithecines evolved.
Homo habilis was the first hominid assigned to the what genus and known to make what.
human genus. H. habilis was known to make and use stone tools.
Homo erectus was
the second species of human to evolve. It arose in Africa 1.5 million years ago and by 500,000 years ago had migrated to Europe and Asia. H. erectus lived in groups, produced efficient stone tools, and was the first hominid to use fire.
Homo habilis evolved from what and how long ago?
It evolved from an australopithecine ancestor about 2 million years ago and survived in Africa for about 500,000 years.
Results from mitochondrial DNA studies suggest that Homo sapiens
evolved from Homo erectus ancestors in Africa about 500,000 years ago. Homo sapiens then migrated throughout the world, evolving into the different human varieties.
60 million years ago
first primates, prosimians, w/ grasping fingers and toes (nails not claws), forward eye placement for binocular (better) depth perception
36 million years ago
some prosimian species evolve to be diurnal
Evolving from diurnal prosimians are three lines of primates that still exist today:
(daylight), enabled by new feature -cones in eyes for color perception.
- Monkeys with larger brains and opposable thumbs replace most diurnal prosimians. Monkeys migrate from Africa to Asia, Central and South America.
- Apes evolve from diurnal prosimians in Africa 30 million years ago w/larger brains than monkeys and no tail. Man and Apes evolved from prosimians NOT monkeys. Chimpanzee are closest ape relative to man (evidence is the similarity in DNA means that our lines diverged in more recent times).
- Hominids evolve from diurnal prosimians.
Hominids - bipedalism
evolves in response to environment change to more grassland. Standing erect enabled them to see over grass further.
Structural differences between hominids and apes that enable or indicates bipedalism:
Apes/Hominids
femurs angled out from pelvis / femurs angled in under from pelvis enables bipedalism
Massive C- shaped spine, enables quadrupedalism / delicate S-shaped spine w/ bone on top of bone enables bipedalism
Spine exits from rear of skull / Spine exits from bottom of skull enables bipedalism
arms longer than legs, enables quadrupedalism / arms shorter than legs indicates bipedalism
long narrow angled pelvis, enables quadrupedalism / Short bowl shaped pelvis indicates bipedalism
3.9 million years ago
Australopithecus appears, earliest known hominid, bipedal and (later) a large brain.
First Australopithecine found in 1924 by Raymond Hart (2.8 million years old) named
Australopithecus Africanus
Lucy a 3.2 million years old A. Afarensis was discovered by Donald Johanson in 1974. Important because:
- She was and still is the most complete early hominids so can be used a reference for other fossil finds
- (At that time) She was the earliest hominid
- Her brain was comparable to an apes (small), which contradicted a prevailing idea of the time - that hominids had large brains before or at the time they became bipedal. Lucy and her kind obviously stood well before later hominids evolved bigger brains
Other Australopithecines found named
A. robustus, A. Boisei, A. afarensis
A. afarensis
oldest (3.9 million) and common ancestor to other Australopithecines and man - did not have a large brain.
3 what species
human (homo) species
Homo habilis
(evolved 2 million years ago in Africa) -
larger brain than Australopithecines. Discovered in 1960. Used tools. Existed 500,000 years.
Homo erectus
(evolved 1.5 million years ago in Africa) - even larger brain, replaced Homo habilis. Oldest fossils found in Africa. Existed 1 million years.
Homo erectus was better than habilis by being able to do what?
-Migrated to Asia and Europe. Out competed and replaced habilis because:
-Made and used BETTER tools (enabled by bigger/smarter brain)
-Made and used fire (enabled by bigger/smarter brain) for:
>Warmth
>Protection
>Cooking for more nutrition and killing pathogens on food
>Extending work day
>Talking (sharing knowledge at night
-Lived in large groups (enabled by empathy - the ability to read minds):
>Safety in numbers
>Division of labor
>More genetic diversity (less inbreeding)
Eugene Dubois did what
observes that orangutans in the zoo resemble humans and goes to Java (where orangutans live) in search of missing link. 1891 discovers Java man (Homo erectus).
1920
Peking Man discovered(also Homo erectus).
Homo sapiens
500,000 years old. Out competed and replaced H. erectus.
Two theories of Sapien evolution:
Evolved in different locations from erectus
Evolved in one location (Africa) and then spread to replace erectus
Evidence supporting evolution of H sapiens ONLY in Africa:
- Modern H. sapiens ancestry is traced using mitochondrial DNA.
- mDNA is used rather than nuclear DNA because it is only passed down from the mother
- so it is more pure
- because they only way it can change from generation to generation is by mutation (nuclear DNA changes by mixing in several events in the sexual reproduction process (crossing-over, flip-flopping, random gametes combination with egg)
- More mDNA differences BETWEEN two modern day Africans
- than BETWEEN two members of any other group
- Means they share a more distant common ancestor
- because there has been more time (since their lines diverged) to accumulate more differences due to random mutations
- which means that Homo sapiens evolve in Africa and THEN migrated out (more recent lines diverged when they reached Europe and Asia)
Neanderthals
First sapiens appear in Europe 130,000 years ago and had BIGGER brains than Homo sapiens of modern appearance which replaced European Neanderthals 34,000 years ago.
Modern H. sapiens had one major advantage -
a brain wiring more capable of communication. Benefit of communication - to share knowledge and build upon prior knowledge (memetic evolution).
Evolution of Communication
Gesture
Sounds
Pictures
Language
Writing
Printing press
Telegraph
Telephone
Radio
TV
Internet
Cell phone
Smart phone
Heads-up display
Method
Gesture
Value
quick
Method
Sounds
Value
quick
Method
Pictures
Value
Can transcend time to future generations & worth 1000 words
Method
Language
Value
More precise, complex, fast
Method
Writing
Value
Transcend time and distance
Method
Printing Press
Value
Mass media - one to many (quick dissemination)
Method
Telegraph
Value
Transcend distance instantly w/problems (Morse code), 1 to 1
Method
Telephone
Value
Transcend distance instantly without/problems, 1 to 1
Method
Radio
Value
Transcend distance instantly. Mass media (1 to many), expensive, have to tune in at certain time
Method
TV
Value
Transcend distance instantly. Mass media (1 to many) w/moving pictures, expensive, have to tune in at certain time
Method
Internet
Value
Has all the above +on demand + FREE for anyone, hypertext connects the dots
Method
Cell Phone
Value
Transcend distance instantly without/problems 1 to 1 ANYWHERE (without wires)
Method
Smart Phone
Value
All of the above ANYWHERE ANYTIME (without wires)
Method
Heads up Display
Value
All of the above ANYWHERE ANYTIME with GPS referenced data
