Why is evolution so controversial?

add [blockcolor=white] and [/blockcolor] codes to get

Enjoy

Just a thought ... If you multiply the curve for "Predicted fixed and near-fixed variants (constant rate model)" by an exponential decay curve for (correctly modeling) the loss of long sections over time you will get a curve that fits the data better than the "Predicted fixed and near-fixed variants (demographic model)" and that this would show that sfs is correct.Enjoy

Seeing as both branches diverge from the Human-Chimp Last Common Ancestor it is logical that each is more closely related to the HCLCA than each other. This would be true for all species descendant from a common ancestor, so this should not be a problem. Not really: Sahelanthropus tchadensis | The Smithsonian Institution's Human Origins Program

quote:

---

Sahelanthropus tchadensis

​

Where Lived: West-Central Africa (Chad)
When Lived: Sometime between 7 and 6 million years ago

​

Sahelanthropus tchadensis is one of the oldest known species in the human family tree. This species lived sometime between 7 and 6 million years ago in West-Central Africa (Chad). Walking upright may have helped this species survive in diverse habitats, including forests and grasslands. Although we have only cranial material from Sahelanthropus, studies so far show this species had a combination of ape-like and human-like features. Ape-like features included a small brain (even slightly smaller than a chimpanzee’s), sloping face, very prominent browridges, and elongated skull. Human-like features included small canine teeth, a short middle part of the face, and a spinal cord opening underneath the skull instead of towards the back as seen in non-bipedal apes.

​

How do we know Sahelanthropus walked upright?

​

Some of the oldest evidence of a humanlike species moving about in an upright position comes from Sahelanthropus. The foramen magnum (the large opening where the spinal cord exits out of the cranium from the brain) is located further forward (on the underside of the cranium) than in apes or any other primate except humans. This feature indicates that the head of Sahelanthropus was held on an upright body, probably associated with walking on two legs.

---

Seeing as this is very close to the time of divergence we would expect this ape/hominid to be very very close to the last common ancestor with chimps, and it may even BE the last common ancestor species.Sahelanthropus - Wikipedia

quote:

---

​

Sahelanthropus tchadensis is an extinct hominine species that is dated to about 7 million years ago, possibly very close to the time of the chimpanzee/human divergence, and so it is unclear whether it can be regarded as a member of the Hominini tribe.[1] ...

---

That is what I would expect the HCLCA skull to look like. Nope. Do you?Enjoy.

And yet a fairly complete skull. Other places where we could look for intermediate traits would be in the hips, knees and feet, but having a full skull means a wealth of information is available. Curiously it is the cranium (skull) that shows a mix of differences between chimp and human traits -- an intermediate mosaic of traits -- from teeth to eyebrows to location of the spine connection. It falls into sequence with other fossils:It is before {B} in this diagram 29 Evidences for Macroevolution: Part 1{A} is a modern chimp, {B} is (B) Australopithecus africanus (STS 5), 2.6 My old.All those skulls except {A} have the same location of the spine to skull connection that shows upright posture and it is an adaptation that allows\facilitates bipedal locomotion.In between Sahelanthropus tchadensis and Australopithecus africanus we have three sets of fossils, starting with Orrorin tugenensis

quote:

---

Nickname: Millenium Man
Where Lived: Eastern Africa (Tugen Hills, central Kenya)
When Lived: Sometime between 6.2 and 5.8 million years ago

​

Living around 6 million years ago, Orrorin tugenensis is the one of the oldest early humans on our family tree. Individuals of this species were approximately the size of a chimpanzee and had small teeth with thick enamel, similar to modern humans. The most important fossil of this species is an upper femur, showing evidence of bone buildup typical of a biped - so Orrorin tugenensis individuals climbed trees but also probably walked upright with two legs on the ground.

---

Now we know that Australopithecus africanus (skull {B} above) was also able to climb trees and walk upright, so this is consilient with hominid evolution.We also have Ardipithecus kadabba:

quote:

---

Where Lived: Eastern Africa (Middle Awash Valley, Ethiopia)
When Lived: Between about 5.8 and 5.2 million years ago

​

Ardipithecus kadabba was bipedal (walked upright), probably similar in body and brain size to a modern chimpanzee, and had canines that resemble those in later hominins but that still project beyond the tooth row. This early human species is only known in the fossil record by a few post-cranial bones and sets of teeth. One bone from the large toe has a broad, robust appearance, suggesting its use in bipedal push-off.

---

And we have Ardipithecus ramidus:

quote:

---

Nickname: Ardi
Where Lived: Eastern Africa (Middle Awash and Gona, Ethiopia)
When Lived: About 4.4 million years ago

​

Ardipithecus ramidus was first reported in 1994; in 2009, scientists announced a partial skeleton, nicknamed ‘Ardi’. The foot bones in this skeleton indicate a divergent large toe combined with a rigid foot — it's still unclear what this means concerning bipedal behavior. The pelvis, reconstructed from a crushed specimen, is said to show adaptations that combine tree-climbing and bipedal activity. The discoverers argue that the ‘Ardi’ skeleton reflects a human-African ape common ancestor that was not chimpanzee-like. A good sample of canine teeth of this species indicates very little difference in size between males and females in this species.

​

Ardi’s fossils were found alongside faunal remains indicating she lived in a wooded environment. This contradicts the open savanna theory for the origin of bipedalism, which states that humans learned to walk upright as climates became drier and environments became more open and grassy.

---

And it is pretty clear (to me) that the ability to walk upright was an earlier adaptation to a mixed ecology. These lineages take the hominid family tree from present day back to the time for the common ancestor species and our divergence from chimpanzees. Their gradual changes in characteristics, where each group is intermediate between ones before and ones after show a clear trend fully explained by evolutionary processes.EnjoyEdited by RAZD, : clrty

Well that would be a good place to start now eh?