Gene Expression

The First Human

The San Jose Mercury News has a review up of Ann Gibbons’ The First Human: The Race to Discover Our Earliest Ancestors. It concludes:

But too many pieces are still missing from the puzzle — including fossils of the ancestors of our closest relatives, chimpanzees and gorillas — to allow for a clear picture of the evolutionary lineage.

So in the end, “The First Human” is a bit like a detective story without a conclusion, or like a detective story that puts Sherlock Holmes, Hercule Poirot, Sam Spade, V.I. Warshawski, Easy Rawlins and Gil Grissom all in the same room, gives them a handful of clues, and lets them argue endlessly about the solution. The characters in Gibbons’ book are almost as colorful and cantankerous as those fictional sleuths. Science writing is rarely this entertaining.

Bones will not tell the whole story. Expect a different sort of excavation, that is, inferences from the genes of humans alive today, to bring to light a lot of the tale in the next few years.

Comments

  1. #1 Fred Gray
    April 26, 2006

    One of my old questions about life was “How long have humans been on this earth?” Or how long ago did we separate from the apes? (The short answer is we are not humans yet as we kill more of our kind than just about any other animal.) So I have narrowed my question down to this: When did the two primate chromosomes fuse to make the human/almosthuman #2 chromosome? Just within a few million years will be close enough for me. I was wondering if it would be 25 MYA or more like 6 MYA? You wanta try?
    Thanks, Fred

  2. #2 NuSapiens
    April 26, 2006

    I don’t expect any good answers to this question for a long time to come. Projects like the HapMap are great, but much more comprehensive data gathering needs to take place if we want to do anything more than scratch the surface or observe surface errata that don’t even data to prehistorical times.

  3. #3 Boknekht
    April 26, 2006

    “How long ago did we separate from the apes”

    But We’re still apes, just different from the others as a result of facing different evolutionary pressures. We didn’t separate from the other apes; we co-evolved from different points in the primate tree, i believe. When did we become less ape-like? Probably only within the last 200,000 years, as our craniums grew larger & our jaws became smaller, & with the emergence of sapiens. But just how far back bipedal apes go isn’t known, as far as i’m aware. Proconsul was bipedal, i think. More interesting questions include when prosimians split or evolved from purgatorious?, & when the great apes emerged from the prosimians. Did human ancestors ever brachiate? There’s evidence that the simian or primate order was much more extensive than it is today, i think. What particular line of tertiary primate-cestors sapiens descend from is an open question. Maybe future mammal genome reconstruction projects will shed some light in these areas. I wonder how much IQ has risen during the last 500KY?

  4. #4 Fred Gray
    April 26, 2006

    It seems to me that the split between Homo and the Chimpanzee line has been said to be around 6 MYA. The Gorilla line, earlier than that, and the Orangutan line before that. Since the Orangutan, Gorilla and the Champanzee all have the 2a and 2b chromosome and the Homo has only one long #2 chrosome,(made by joining 2a and 2b),then the split off between the Homo and Chimpanzee line would be the date that I am looking for. In other words, Homo has been on this earth for more like 6 million years.

    Aye?
    Fred

  5. #5 razib
    April 27, 2006

    In other words, Homo has been on this earth for more like 6 million years.

    Aye?

    well…the last common ancestor of humans and chimps lived ~ 6 million years ago. that does not mean that homo has been around for 6 million years…though these taxonomic issues are to some extent semantics.

    Probably only within the last 200,000 years, as our craniums grew larger & our jaws became smaller, & with the emergence of sapiens.

    a minor note, the cranial capacity increase spanned 2 million to 200,000 years BP, give or take some spurts and flat periods. in other words, anatomically modern crania preceded anatomically modern behavior.

  6. #6 Paolo
    May 14, 2006

    Can Bonobos and Common Chimpanzee produce fertile offspirngs?

  7. #7 Juan
    May 18, 2006

    “We” only date back 60,000 radio carbon years. Genetically. The assimilation of this fact into the general knowledge base (50 years?) will probably difuse alot of the present debate amongst the creation v. evolution crowd. Looks like both of them are wrong to some degree. And both right. “We” did come from a common human ancestor. It wasn’t 6 or 7 thousand years ago. But it wasn’t hundreds of thousands of years ago either!

  8. #8 Fred Gray
    May 24, 2006

    Hi Juan,
    I am of the camp that Homo is evolving very rapidly. If, as you say we have only been anatomically modern humans for 60,000 years, that is fine. I count the earlist recorded Chordate of the Ediacaran Period in my personal ancestry. I was just trying to find out when Homo somethinganother separated from their ape-like ancestors. Looks like 5 or 6 million years BP.

    Thanks for the 60,000 YBP, I will look at that also, but I don’t care how ape-like we once were as much as when our #2 chromosome was fused from the two ape-like ancestor’s chromosomes. Looks like people in the know don’t want to put too much weight on that fused chromosome thing.