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