Cambrian explosion

Joining the list of causes of the Cambrian explosion …

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An article in Nature attempts to account for the Cambrian explosion in part as follows:

Formation of the ‘Great Unconformity’as a trigger for the Cambrian explosion

From the Abstract:

. Here we use new stratigraphic and geochemical data to show that early Palaeozoic marine sediments deposited approximately 540–480?Myr ago record both an expansion in the area of shallow epicontinental seas and anomalous patterns of chemical sedimentation that are indicative of increased oceanic alkalinity and enhanced chemical weathering of continental crust.

The resultant globally occurring stratigraphic surface, which in most regions separates continental crystalline basement rock from much younger Cambrian shallow marine sedimentary deposits, is known as the Great Unconformity.

Thus, the formation of the Great Unconformity may have been an environmental trigger for the evolution of biomineralization and the ‘Cambrian explosion’ of ecologic and taxonomic diversity following the Neoproterozoic emergence of animals.

The last two explain-aways to whistle across this desk were: deposits of sediment enabled life forms to build shells and a natural selection war occurred around eyes. As to the latter, well, perhaps so, but the suddenly emerging Cambrian eyes were very advanced, even by today’s standards. Wonder what the next explain-away will be after this.

They are still looking for something easy and it isn’t there.

See also: New Scientist on the subject.

Steve Meyer’s new book, Darwin’s Doubt, is overwhelmed with trolls … and customers … at Amazon

2 Replies to “Joining the list of causes of the Cambrian explosion …

  1. 1
    bornagain77 says:

    minor problem with their theory, it was recently found that a change in environment leads to extinction of species and not to the origination of species as they suppose:

    New Species, Darwin Wrong Again – June 28, 2013
    Excerpt: By examining the fossil records of 19 Cenozoic terrestrial mammal clades, Quental and Marshall discovered extinction rates exceeding the formation rates of new species. Fossil record evidence demonstrates that the rate of extinction far exceeds the formation of new species.
    “We find their diversity loss was not just a consequence of ‘gamblers ruin,’” the investigators reported, “but due to the evolutionary loss to the Red Queen, a failure to keep pace with a deteriorating environment.”
    The Red Queen hypothesis named after Lewis Carroll’s character who, in the 1871 book “Through the looking glass,” said her country was a place where “it takes all the running you can do, to keep the same place.”
    “In biology, this means that animals and plants don’t just disappear because of bad luck in a static and unchanging environment, like a gambler losing it all to a run of bad luck at the slot machines,” explained Robert Sanders, science writer for University of California, Berkeley in the ScienceDaily article entitled “The Red Queen was right: life must continually evolve to avoid extinction.”
    “Instead, they face constant change,” Sanders continues, “a deteriorating environment and more successful competitors and predators — that requires them to continually adapt and evolve new species just to survive.” All is well, except that the investigators found that extinction was the rule. The investigators found no evidence for the emergence of any new species.
    These fossil record findings undermine Darwin’s theory that changing environments are a driving force of evolution:
    “under changing conditions of life, there is no logical impossibility in the acquirement of any conceivable degree of perfection through natural selection.”
    Rather than acquiring “any degree of perfection” in the wake of environmental changes, the effect increased the rate of extinction, not speciation.
    In the article entitled “Scientists examine historical loss of diversification of species leading to extinction” published in in Nature World News, Marshal note that “virtually no biologists thinks about the failure to originate as being a major factor in the long term causes of extinction. But we found that a decrease in the origin of new species is just as important as increased extinction rate in driving mammals to extinction.”
    When species are challenged by changing environments, rather than adapting, the pendulum swings in favor of destruction?extinction rather than “the acquirement of any conceivable degree of perfection.” Darwin’s natural selection pendulum favors extinction, not the formation of new species.
    http://www.darwinthenandnow.co.....ong-again/

  2. 2
    jerry says:

    Wonder what the next explain-away will be after this.

    This morning the Teaching Comapny/Great Courses came out with a new course titled the “A New History of Life.” It has 36 1/2 hour lectures.

    http://www.thegreatcourses.com.....x?cid=1520

    . 1? The Interconnected Earth
    . 2 The Vast Depths of Earth Time
    . 3 Fossil Clocks
    . 4 Paleontologists as Detectives
    . 5 The Shifting Surface of Planet Earth
    . 6 Earliest Origins—Formation of the Planet
    . 7 Origins of Land, Ocean, and Air
    . 8 The Early Chemical Evolution of Life
    . 9 Hints of the First Life Forms
    . 10 How Life Transformed the Early Earth
    . 11 Snowball Earth—Another Crisis
    . 12 Metazoans—Life Grows Up
    . 13 Incredible Variety—The Cambrian Explosion
    . 14 Window to a Lost World—The Burgess Shale
    . 15 The Forgotten Fossils in Earth’s Story
    . 16 Introduction to the Great Mass Extinctions
    . 17 The Collapse of Earth’s First Eden
    . 18 Making the Break for Land
    . 19 Getting a Backbone—The Story of Vertebrates
    . 20 The Evolution of Jaws
    . 21 These Limbs Were Made for Walking?
    . 22 Tiktaalik—The Search for a Fishapod
    . 23 Carboniferous Giants and Coal
    . 24 Amniotes—The Shape of Things to Come
    . 25 Permian Extinction—Life’s Worst Catastrophe
    . 26 Finding the Killer—The Greenhouse Earth
    . 27 The Dinosaurs Take Over
    . 28 Letting the Dinosaurs Speak—Paleobehavior
    . 29 Conquering the Air—The Evolution of Flight
    . 30 Monsters of the Deep—Mesozoic Oceans
    . 31 The Cretaceous Earth—A Tropical Planet
    . 32 The Sky Is Falling—End of the Dinosaurs
    . 33 The Collision of North and South America
    . 34 The Rise of Mammals and the Last Ice Age
    . 35 The Humble Origins of Human Beings??
    . 36 The Conscious Earth

    I have no idea what it says since it just came out this morning and I have not purchased it.

    Relevant to Meyer’s book. I am over half way through and the battle line is set on the relevance of an article by Long in 2003

    Nat Rev Genet. 2003 Nov;4(11):865-75.
    The origin of new genes: glimpses from the young and old.
    Long M, Betrán E, Thornton K, Wang W.
    Source
    Department of Ecology and Evolution, The University of Chicago, 1101 East 57th Street, Chicago, Illinois 60637, USA. mlong@uchicago.edu
    Abstract
    Genome data have revealed great variation in the numbers of genes in different organisms, which indicates that there is a fundamental process of genome evolution: the origin of new genes. However, there has been little opportunity to explore how genes with new functions originate and evolve. The study of ancient genes has highlighted the antiquity and general importance of some mechanisms of gene origination, and recent observations of young genes at early stages in their evolution have unveiled unexpected molecular and evolutionary processes.

    Matzke and others did another literature bluff in 2004 after Meyer’s article “The Origin of Biological Information and the Higher Taxonomic Categories” appeared. It mainly relied on the Long article

    Meyer discusses in detail in his new book the Long article and several others that have appeared since it came out. The Long article essentially hand waives in new genetic information. Meyer use the sub-title “Word Salad” for the various non scientific terms used to justify new biological information.

    The evolution argument has always been over the creation of new alleles so this topic while discussed a lot should be the main focus from now on. Where do all those ORFans come from?

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