Hi everyone. Just a few links that may be of benefit to people.
- Human-chimp genetic similarity
en.wikipedia.org/wiki/Human_evolutionary_genetics#Sequence_divergence_between_humans_and_apes
The draft sequence of the common chimpanzee genome published in the summer 2005 showed the regions that are similar enough to be aligned with one another account for 2400 million of the human genome’s 3164.7 million bases[18] – that is, 75.8% of the genome. This 75.8% of the human genome is 1.23% different from the chimpanzee genome in single nucleotide polymorphisms[18] (changes of single DNA “letters” in the genome). Another type of difference, called indels (insertions/deletions) account for another ~3 % difference between the alignable sequences.[18] In addition, variation in copy number of large segments (> 20 kb) of similar DNA sequence provides a further 2.7% difference between the two species.[19] Hence the total similarity of the genomes could be as low as about 70%.
- The family tree of human beings
When I was a teenager, the common view among anthropologists was that orang-utans, gorillas and chimps belonged in one family (Pongidae) while humans belonged in another (Hominidae). That is a minority view now as DNA evidence seems to suggest that chimps and humans are closer than chimps and gorillas. However, a new paper argues that the interpretation of the DNA evidence is mistaken.
Here’s a link to a very original paper by a Chinese researcher, Shi Huang, who has examined various kinds of primate DNA and formulated a bold new maximum genetic diversity hypothesis, which appears to successfully account for the peculiar anomalies and internal contradictions in the molecular clock dating of splits between animal lineages. Huang does a good job of exposing the flaws in molecular clock dating.
Huang’s surprising conclusion is that orangutans, gorillas and chimps are all pongids (apes), while humans belong to a separate group which diverged from the apes 17.3 million years ago. Huang has carefully checked his maximum genetic diversity hypothesis against other mammalian lineages, and it agrees well with the paleontological data.
precedings.nature.com/documents/3794/version/1
- Mitochondrial Adam and Eve
For my part, I favor Germain Grisez’s suggestion that Adam was the original designated head of the human race, and that he made the fateful decision that we know today as the fall. Anyway, here’s what the genetic evidence says.
en.wikipedia.org/wiki/Mitochondrial_Eve
Mitochondrial Eve is believed to have lived between 150,000 to 250,000 years BP, probably in East Africa, in the region of Tanzania and areas to the immediate south and west.[1] She lived during a period of time when Homo sapiens were developing as a species separate from other hominid species. She lived in a population of between perhaps 4000 to 5000 females capable of producing offspring at any given time.
en.wikipedia.org/wiki/Y-chromosomal_Adam
Y-chromosomal Adam is named after the Biblical Adam. While the name implies that Y-chromosomal Adam was the only living male of his time, it is important to understand that he probably co-existed with a large population of human males. None of Y-chromosomal Adam’s male contemporaries, however, have a direct unbroken male line to the present day. Either their lines died out entirely, or at least one generation within each line produced only daughters, who could not pass their male parents’ and ancestors’ Y-chromosomes to their own children.
Y-chromosomal Adam probably lived between 60,000 and 90,000 years ago, judging from molecular clock and genetic marker studies. While their descendants certainly became close intimates, Y-chromosomal Adam and mitochondrial Eve are separated by tens of thousands of years.
- Human uniqueness
bbsonline.org/Preprints/Penn-01062006/Referees/Penn-01062006_bbs-preprint.htm
To be published in Behavioral and Brain Sciences (in press)
Cambridge University Press 2007
Darwin’s mistake: Explaining the discontinuity between human and nonhuman minds
by Derek C. Penn, Keith J. Holyoak and Daniel J. Povinelli
There is a profound functional discontinuity between human and nonhuman minds. We argue that this discontinuity pervades nearly every domain of cognition and runs much deeper than even the spectacular scaffolding provided by language or culture can explain. We hypothesize that the cognitive discontinuity between human and nonhuman animals is largely due to the degree to which human and nonhuman minds are able to approximate the higher-order, systematic, relational capabilities of a physical symbol system…
While the advantages of symbolic communication are enormous, the adaptive advantages of being able to reason in a relational fashion have a certain primacy over the communicative function of language. It is quite difficult to imagine how communicating in hierarchically-structured sentences would be of any use without the ability to entertain hierarchically-structured thoughts. But it is quite easy to imagine how the ability to reason about higher-order relations—particularly causal and mentalistic relations—might be highly adaptive without the ability to communicate those thoughts to anyone else.
…In any case, regardless of which factors most strongly contributed to the unique evolution of the human brain, language alone is no longer directly and entirely responsible for the functional discontinuity between extant human and nonhuman minds.
…Our most important claim in this paper is simply that whatever “good trick” (Dennett 1996) was responsible for the advent of human beings’ ability to reinterpret the world in a symbolic-relational fashion, it only evolved in one lineage—ours. Nonhuman animals didn’t (and still don’t) get it.
I hope these links help. Enjoy!
