I know the sahelanthropus is believed to be one of the links that had shin bones and toe bones that allowed for the start of bipedalism, though I was wondering how chimpanzee like they were and what recent research has found about the “common ancestor” link for human evolution.
13 embryos ranging from 9 to 13 weeks were immunostained for muscles.
They found a number of muscles present other adult tetrapods, but which disappear during human development.
Some highlights of the article from the whyevolutionistrue blog
> Here are two of the fetal atavistic muscles. First, the dorsometacarpales in the hand, which are present in modern adult amphibians and reptiles but absent in adult mammals. The transitory presence of these muscles in human embryos is an evolutionary remnant of the time we diverged from our common ancestor with the reptiles: about 300 million years ago. Clearly, the genetic information for making this muscle is still in the human genome, but since the muscle is not needed in adult humans (when it appears, as I note below, it seems to have no function), its development was suppressed.
> Here’s a cool one, the jawbreaking “epitrochleoanconeus” muscle, which is present in chimpanzees but not in adult humans. It appears transitorily in our fetuses. Here’s a 2.5 cm (9 GW) embryo’s hand and forearm; the muscle is labeled “epi” in the diagram and I’ve circled it
Now, evolution and common descent explain very well these foetal anatomy findings.
How does creationism with humans being a separate kind from all other organisms explain these foetal anatomical findings?
Common design? Well, we don't have those muscles. Genetic entropy? Funny how during foetal development we have some same muscles as chimpanzees and amphibians/reptiles, as if we had a common ancestor.
Looking forward to some creationists putting their hands up with some explanations!
It appears that due to "fundamental forces", the (methyl)cytosine deamination to thymine (C>T) is a disproportionately common source of mutation. In conjunction with the deamination of guanine to adenine (G>A), and deamination of cytosine to uracil (again ultimately causing a C>T transition if you recall uracil is the RNA replacement of thymine), these processes cause almost 70% of mutations to be "transition" mutations - where purines "transition" to another purine, and a pyramidine "transitions" to another pyramidine - ie T<>C/G<>A mutations); and only 30% of mutations to be "transversions" - that is purine to pyramidine, or pyramidine to purine - ie G<>C/A<>T/A<>C/G<>T mutations.
The preponderance of the C>T transition means that that this mutation is targeted by ASSUMING G-T mismatches have the T as the error by having thymine-DNA glycosylase excise the presumed erroneous thymine nucleotide when the mismatch is detected (which as you can see, is more often than not, a correct assumption).
This biased randomness can be seen in comparing human genome de novo mutations and single nucleotide polymorphisms - the 1000 genomes project demonstrates that most of our genetic differences are indeed the result of T<>C/G<>A mutations.
Similarly, if humans and chimpanzees come from a common ancestor by mutations, then we would expect a similar mutation spectrum if the differences are by a mutational process. And, indeed, this is what we see!! The following graph includes the fixed nucleotide differences between chimpanzees... keep reading on reddit ➡
My friend is in good shape but is by no means peak human performance. The chimp is an average of the species
Round 1: A chimpanzee breaks into the house, he’s already got the weapons on him
Round 2: Random encounter in an open field
Round 3: Round 1 but with his dog, (Pitbull, ~55 lbs)
Round 4: Round 2 blood lusted
Bonus: He breaks into the gorillas encounter with his roommates (5’10 ~190 & 5’9 ~160). Can the three of them capture a chimpanzee?
I'm probably making many assumptions that show a general lack of understanding of chimpanzee behavior, and I apologize for that. Hopefully someone will still try to provide an explanation and show errors in my thinking.
So my questions are:
Do most infants have access to a similar amount of food? Is there a ranking system that determines how much food different infants can get? Which factors lead to inequality in terms of nutrition, if that occurs at all?