Who are primates closest relatives?. bats and rodents. What distinguishes primates from bats, rodents and other mammals?. partial transition from claw to nail reduced ability to synthesize vitamin C litter size of one (among normal healthy females) opposable thumbs
bats and rodents
What distinguishes primates from bats, rodents and other mammals?
partial transition from claw to nail
reduced ability to synthesize vitamin C
litter size of one (among normal healthy females)
reduction of the olfactory (smell) system
highly developed hand-eye coordination
(i.e., binocular, stereoscopic color vision)
fossils having these features date back to 60 million years ago
loss of tail
partial bipedality (walking upright)
skull aligned vertically over the jaw region
short facial snout
Fossils with these features date back to as old as 31 Ma
rainforest action network
sexual activity decoupled from reproduction (a very rare trait)
omnivory (others are strictly vegetarians)
delayed sexual maturity until teen or pre-teenage
prominent external genitalia for both male and female
a mandible joint that is positioned in the middle with respect to the side profile of the skull.
compared to chimps?
loss of knuckle-walking
(although two australopithecines have indications of knuckle-walking)
loss of opposable 5th toe
Fossils having these features date back to as old as 5-6 Ma.
"Toumaï", in common Sahelanthropus tchadensis
discovered in 2001 in Chad (southern Sahara)
complete skull with a slightly smaller brain than modern chimps
hole in the back of skull suggests that it was not fully bipedal
…but muscle attachments from neck to back of skull suggest that it was more bipedal than chimps
canines and thicker tooth enamel (as well as eye brow ridges) are more human-like than chimp-like
S. tchadensis (Toumai) fossils date from 6-7 million years ago
Are there any fossils that resemble something like the last common ancestor of chimpanzees and humans?
Jim Foley in common
OK, fine, but if this supposed link between humans and chimpanzees is really correct, and our lineages diverged about 6 million years ago, there should be fossil intermediates between our last common ancestor and modern humans, right?
Australopithecus afarensis in common
fossils from 3 to 3.9 million years ago
small brain, but larger than modern chimps
otherwise the skull is more chimp- than human-like, except for the teeth
the pelvis and leg bones are more human-like than chimp-like
the length of the fingers is a bit more chimp-like, suggesting some connection with tree climbing, but otherwise the hands are more human-like
from Humankind Emerging,
B. Campbell (ed.)
A. africanus in common is very similar to A. afarensis, except A. africanus is slightly more recent (between 2 and 3 million years old), slightly larger in total body (and possibly brain) size, and had an even more human like(parabolic) jaw
from Humankind Emerging,
B. Campbell (ed.)
The (in)famous in common Australopithecus afarensis fossil “Lucy”
“The one that is in the textbooks now that is the most famous is called Lucy. How many have ever heard of Lucy before? Better known as australopithicus atherensis [sic], scientific name. Donald Johanson found Lucy at Dar [sic] Valley, Ethiopia in 1974; it was 40% of the skeleton. This is considered the most complete skeleton ever found. There is a real controversy about the knee joint. The knee joint that he found a mile and a half away from the rest of the skeleton was labeled in National Geographic as “Lucy’s Knee”, Donald never corrected them; it was not Lucy’s knee found a mile and a half away. He let the error slip through because he wanted them to think, “well maybe that is the same.” There is a long story on that; 200 feet deeper in the strata, by the way.”
-Kent Hovind AKA “Dr. Dino” – a creationist – South Carolina lecture transcript
Johanson never said that the knee in question was Lucy’s – but he did say (and the
evidence supports this) that it from another A. afarensis individual. He also has clearly
stated this in his writings (including his book on Lucy). Also, the knee is not
the only evidence for bipedality in Lucy and other Australopithecus fossils. This is from a
Q&A period following one of Johanson’s talks:
Q. How far away from Lucy did you find the knee? A. Sixty to seventy meters lower in the strata and two to three kilometers away.
This has later been distorted by many creationists (including Hovind) to mean that Johanson was talking about Lucy’s knee. Hovind has agreed to stop using this claim in his talks, though a search of his website still finds it there.
Homo erectus in common
existed between 1.8 million and 800,000 years ago
skull is very human like (much more so than Australopithecus species)
brain size almost double that of Australopithecus, and increased as time passed
fossil finds suggest use of fire and increasingly complex stone tools
(1.7 million years old)
(between 0.8 and
1.7 million years old)
(300,000 years old)