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Education Science

Evolution of Mammals Re-evaluated 249

AaxelB writes "A study described in the New York Times rethinks mammalian evolution. Specifically, that the mass extinction of the dinosaurs had relatively little impact on mammals and that the steps in mammals' evolution happened well before and long after the dinosaurs' death."
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Evolution of Mammals Re-evaluated

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  • by Anonymous Coward on Wednesday March 28, 2007 @04:28PM (#18519999)
    Is "your friend" TFA? Because that same goddamn paragraph is in the fucking article!
  • by rucs_hack ( 784150 ) on Wednesday March 28, 2007 @04:45PM (#18520225)
    I thought it was about six million years, could be wrong though.

    The big thing was grass, it hadn't been around for most of the time the dinosours had existed. The domination of grasses after the CT event really helped the spread of species
  • Re:This is Great (Score:5, Informative)

    by Coryoth ( 254751 ) on Wednesday March 28, 2007 @04:50PM (#18520291) Homepage Journal

    Until the next "re-thinking." Will we ever have hard evidence, or just thought experiments?
    But we do have hard evidence - indeed it was hard evidence that helped lead to this rethinking. Recently there have been a number of finds of surprisingly large mammals that are much older than had previously been expected. They include a beaver like (pre)-mammal [wikipedia.org] from the Jurassic that was almost half a metre long, discovered in 2004, and two species large carnivorous mammal from the cretaceous [wikipedia.org] (dated to about 130 million years ago - or 65 million years prior to the dinosaur extenction) which were discovered in 2000 and 2005. Such large mammals (relatively speaking) during the time of the dinosaurs draws into question the previous belief that mammals were restricted to small rat/mouse like scavengers at that time. Instead we see evidence of large, active, meat eating mammals. This implies that mammals were rather less marginalised during the dinosaurs "reign" than previously thought, and imples that mammal evolutionary history needs to be rethought accordingly.
  • by saforrest ( 184929 ) on Wednesday March 28, 2007 @04:53PM (#18520343) Journal
    If you read The Ancestor's Tale [amazon.com] by Richard Dawkins, you'll find that recent genetic evidence suggests that many of the distinct branches of modern mammals predate the K-T extinction.

    In particular, by the time of the K-T extinction, I believe that the primate lineage had already separated from rodents, as well as the laurasiatheres [wikipedia.org] (all hoofed mammals, lions, tigers, bears, etc.), xenarthrans [slashdot.org] (armadillos, sloths, etc.), and afrotheres [wikipedia.org] (elephants, manatees, anteaters, etc.).

    So, while most mammals in the Cretaceous may still have been tiny shrew-like creatures scurrying around in the underbrush, many of the modern lineages had already come into separate existence.

    It is also interesting to read, in the book, that our nearest non-primate relatives aside from the tree shrews are rodents. I can sort of see it: give a mouse a little more finger dexterity and it wouldn't not that different from a lemur. It also might explain why rodents are such good laboratory specimens.
  • by victorvodka ( 597971 ) on Wednesday March 28, 2007 @04:58PM (#18520401) Homepage
    Dude you said "cambrian" - there was a cambrian explosion too and perhaps that's what you mean. But here we're talking about the Cretaceous, 65 Million years ago instead of 600 Million years ago.
  • Re:This is Great (Score:3, Informative)

    by Coryoth ( 254751 ) on Wednesday March 28, 2007 @05:20PM (#18520679) Homepage Journal
    I should add that these fossil discoveries lead to various people taking a more serious look at the presumed facts of mammal evolution and were the catalyst for a "rethink", however there is even more "hard evidence" in the paper cited by the NYT article which was a far more detailed study looking at far more fossil (and apparently molecular) evidence.
  • by Harry Coin ( 691835 ) on Wednesday March 28, 2007 @05:20PM (#18520681)

    Nope. It's not satire. It was created by Andrew Schlafly, son of arch-conservative anti-femininst Phillys Schlafly [wikipedia.org], and is used by her Eagle Forum [wikipedia.org].

    If the ideas presented on that site induce laughter, it is because neoconservative ideas are completely ridiculous. Really, Mark Twain couldn't produce satire so deep. I honestly hope that the GOP uses that site as their definitive reference. Within two generations, they'll be too stupid to breed.

  • by Daniel Dvorkin ( 106857 ) * on Wednesday March 28, 2007 @07:43PM (#18522543) Homepage Journal
    There is obviously no evidence that the mutations which gave rise to speciations were "random" and not in some way directed, naturally or supernaturally, or otherwise forced in some particular direction.

    "Obvious" if you ignore pretty much all work in molecular genetics at least since Watson and Crick.

    Once we arrive at a better understanding of how DNA works, perhaps it will be possible to form mathematical models to determine whether or not the "random mutation" theory is feasible.

    You mean, the way bioinformaticists and statistical geneticists do all the time, right now, and have been for years?

    Maybe it's only feasible during intermittant radiation events that decimate populations by causing widespread mutations, leaving a few individuals with improvements, who go on to reproduce and build up populations again. Maybe it's not possible at all.

    Do you have any data, at all, that would support either one of these hypotheses? Or are you just cut'n'pasting from some ID site somewhere?
  • by toadlife ( 301863 ) on Wednesday March 28, 2007 @09:32PM (#18523549) Journal
    One small correction that doesn't refute your point. It *rained* for 40 days, but after the rain stopped, the Ark was adrift for several months before finding land again.
  • by testpoint ( 176998 ) on Thursday March 29, 2007 @01:10AM (#18524905)
    I have recently examined the Marzeah Papyrus (7th century B.C.), fragments of the dead sea scrolls, septuagint leviticus , septuagint exodus and Gospel of John fragments all from the 3rd century A.D. Modern, nonparaphrased, versions of the Bible, corresponding to these fragments are accurately translated.

    Many of the original writers and earliest translators could write and speak multiple languages. While you might consider them superstitious they weren't illiterate. William Tyndale, a 16th century scholar and translator was fluent in eight languages. His work influenced Shakespear and the King James version of the Bible.

    Tyndale was strangled and burned at the stake because a version of the Bible that could be read by all, transferred power from the King and the Pope to the church, which Tyndale translated as congregation or congress (people) rather than church (hierarchy). Many credit Tyndale and his translation for furthering the concepts of representative democracy, individual responsibility, and equality.
  • by Yoozer ( 1055188 ) on Thursday March 29, 2007 @02:17AM (#18525235) Homepage

    The Noachian flood is falsifiable on so many different levels - it really only takes a few minutes of unbiased thinking.
    And the idea of having 8 people shovel out massive amounts of manure. Every day. Goodness, what a job.

    And the idea that if you rise all the waters you'll get a pressure-cooker of an atmosphere.

    Not to mention the structural integrity of the boat.
  • by Fordiman ( 689627 ) <fordiman@ g m a i l . com> on Thursday March 29, 2007 @06:05AM (#18526215) Homepage Journal
    Evolution, the historical record of species evolution on earth is being rethought, as there is new evidence to refine our understanding of it, and is as yet theoretical.

    Evolution, the process of speciation (the forking off of species) and adaptation through natural selection, is quite firmly proven.
  • by Hognoxious ( 631665 ) on Thursday March 29, 2007 @07:24AM (#18526477) Homepage Journal

    Evolutionary is just a theory, not a law
    It's neither - it's an adjective, meaning of, or pertaining to, evolution.
  • by arminw ( 717974 ) on Thursday March 29, 2007 @12:48PM (#18530031)
    .....My question is what color was the sky prior to Noah's flood?.....

    You are asking the wrong question. It should be: "Did it not ever rain before the flood?" To make a rainbow, the color of the sky is irrelevant. It takes only rain drops and sunlight. Since the sun did shine before the flood, it must have been the absence of rain that prevented rainbows before the flood.

    In order for rain to happen, two things are needed. 1) a low enough temperature and 2) some particles in the saturated air around which drops can form. If conditions before the flood were such that BOTH of these requirements never were met, then there would have been no rain. We are in fact told in Gen 2:5-6 "For the LORD God had not caused it to rain upon the earth, and there was no man to till the ground. 6 But there went up from the earth a mist and watered all the face of the ground."

    Since you are ignorant by something as simple as to how a rainbow is formed, it doesn't surprise me that you show ignorance in your understanding of God and the Bible.

"An organization dries up if you don't challenge it with growth." -- Mark Shepherd, former President and CEO of Texas Instruments