Tuesday, January 19, 2010

Communal Egg Laying: Evolution Over Easy

Evolution predicts that the designs of species are often influenced as much by history as much as by need. When we see similar structures in cousin species it is because they inherited the design from a common ancestor. That particular design was probably not the best for each of the different species, but it was available.

On the other hand, when we see similar structures in more distant species it is because the design was needed. The design just happened to arise in the different lineages, and was selected because it helped. Given these two general explanatory mechanisms evolution can explain a wide variety of patterns. But not all. Sometimes cousin species have differences that are too pronounced. And likewise, sometimes distant species have similarities that are too pronounced.

Or sometimes the patterns are so jumbled they simply defy evolution's expectations. Consider, for example, the behavior of communal egg laying. This behavior, where neighbors pool their eggs in a common nest, is widespread among animals including mammals, birds, amphibians, reptiles and insects. And although widespread, the pattern is complex. In any pair of cousin species, the behavior of communal egg laying may or may not be conserved.

The figure above, for instance, shows an evolutionary tree representation of different lizard families. The indicated families contain communal egg laying species. Evolutionists must imagine that communal egg laying evolved over, and over, and over, for different reasons in very different species in a wide range environments. But yet in cousin species it evolved in the one but not the other.

Of course evolution doesn't think twice about such quandaries. The right mutations, whatever they were, came along, over, and over, and over without causing a mutational overload to produce a never ending stream of communal egg laying experiments. So not only does evolution explain similarities between both neighboring and distant species, it also explains everything in between.

12 comments:

  1. Cornelius Hunter: Sometimes cousin species have differences that are too pronounced.

    There is nothing about unique protein variants that defies evolutionary explanations. Many can be shown to be related to existing proteins in the lineage.

    Cornelius Hunter: sometimes distant species have similarities that are too pronounced.

    Behe's experiment with histones does not represent a falsification. Being highly conserved does not mean that mutations will necessarily disable the histone. Selective differences in mutants may only become apparent in wild populations, and even then, only over time. The same is true for knock-out experiments and ultra-conserved regions.

    Cornelius Hunter: Of course evolution doesn't think twice about such quandaries.

    Maybe evolution doesn't, but evolutionary biologists are very interested in all the details of life, including behavioral characteristics.

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  2. Zachriel: Selective differences in mutants may only become apparent in wild populations, and even then, only over time.

    As an example in extremis, consider a Jovian scientist experimenting with a population of humans in a laboratory situation. The scientist removes bits and pieces of the human brain and discovers that in many cases, the humans can grow and reproduce quite as well as those without the dissection. The Jovian concludes that much of the brain is extraneous and has no significant biological function.

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  3. Cornelius -

    "Evolutionists must imagine that communal egg laying evolved over, and over, and over, for different reasons in very different species in a wide range environments. But yet in cousin species it evolved in the one but not the other."

    That is not the conclusion I would arrive at. It's not as if these lizards all have different and unique egg-laying habits. The only consideration you are giving is whether they lay communally, yes or no.

    So lets imagine lots of related species of lizards, all with a habit of egg-laying communually. For some species this will be more of an advantage than for others. For some it may be a actual disadvantage. For this later group there will be a selection pressure to repress or otherwise defy the instinct to lay communually.

    So it's not that each species individually develops the instinct to lay communually. But that if all the species have a genetic disposition for this habit, then some species will find it advantageous to go against it.

    A much simpler and more likely scenario, surely?

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  4. Darwinism sucks.

    Always the same inane boring nonsense. Everything is survival for survival's sake. It's nothing but materialism's aimless existence.

    Why should anything survive?

    Mindless nature knows nor cares nothing of survival or no survival.

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  5. Zachriel:

    =========
    Behe's experiment with histones does not represent a falsification. Being highly conserved does not mean that mutations will necessarily disable the histone. Selective differences in mutants may only become apparent in wild populations, and even then, only over time. The same is true for knock-out experiments and ultra-conserved regions.
    =========

    Evolutionary prediction: For functionally unconstrained DNA, similar sequences should not be found in distant species. The corollary to this prediction is that similar DNA sequences found in distant species must be functionally constrained.

    Reality: DNA is conserved.

    Evolutionary reaction #1: That DNA must be functionally constrained.

    Reality: The evidence indicates it is functionally unconstrained.

    Evolutionary reaction #2: That DNA must be functionally constrained in a way undetectable to us.

    http://www.stephenjaygould.org/ctrl/flew_falsification.html

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  6. Cornelius Hunter: Evolutionary reaction #2: That DNA must be functionally constrained in a way undetectable to us.

    It's not some vague unknown, but a problem with the test.

    Consider the Jovian scientist pointing to genetically lobotomized humans that grow and reproduce quite normally in the lab, then concluding that the cerebrum is functionally unconstrained. And yet, we know that humans in the wild are strongly selected for their cognitive abilities. The Jovian scientist can't see this because his test is faulty. The selective differences between humans is not expressed in the artificial environment of the Jovian lab.

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  7. Hitch -

    "Always the same inane boring nonsense. Everything is survival for survival's sake. It's nothing but materialism's aimless existence."

    I fail to see the point of your complaint.

    "Why should anything survive?"

    Because the organisms who try to survive will stand a much better chance of surviving than those who don't. Organisms who don't try to survive generally won't. Their self-uninterested genes will be removed from the gene pool. Meanwhile, those organisms who are simply better at surviving to reproduce will out-reproduce those who are less good at it.

    "Mindless nature knows nor cares nothing of survival or no survival."

    That is because nature is not an entity which has a mind capable of knowing or caring for such things. Again, what is the substance of your complaint?

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  8. Ritchie:
    You missed the point - not surprising.

    As for your first remark - it the oft repeated Darwinist mantra: "things that are fit survive and things that survive are fit, (but I have no idea why anything wants to survive)".

    Darwinists erroneously think that reproduction (survival)is the only reason in the universe.

    Darwinists persist in chasing their tails and going nowhere in tautologies like the above, all the time.

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  9. Hitch -

    "You missed the point - not surprising."

    That's what I said. You're not making your point very clearly. Can you elaborate, please?

    "As for your first remark - it the oft repeated Darwinist mantra: "things that are fit survive and things that survive are fit, (but I have no idea why anything wants to survive)"."

    I fail to see the problem. It is correct that things that are fit tend to survive and the things which survive tend to be the fittest. Are you claiming this is untrue?

    As for WHY things want to survive, well, if they didn't then they probably wouldn't survive, would they? It is only the things which want to survive which actually survive and thus reproduce. Things which don't want to survive die pretty quickly.

    "Darwinists erroneously think that reproduction (survival)is the only reason in the universe."

    This is one of the most ridiculous things I've heard for a very long time.

    For a start, by 'Darwinists' I assume you mean people who accept the fact of evolution. Secondly, we don't think survival/reproduction is the only reason in the universe at all.

    What is the reason I have a headache? The reason is that I didn't get much sleep last night. What is the reason I have the heating on? The reason is that it is cold outside. What is the reason I have shoes on my feet? The reason is that I put them on my feet.

    See? I accept evolution and I can see that other 'reasons' exist.

    I suspect this isn't quite your point. But again, I can't see what point you ARE trying to make. Can you state it any clearer?

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  10. Untrue, Ritchie. Survival has nothing to do with fitness.

    Just watched a NG show on snakes. Out of 28 eggs laid, only two survived. They simply survived because 28 snakes laid in one go allowed enough time for a couple to escape notice. Predators in the area were busy chowing down on the other 26 and had no time for the 'escapees'.

    Or, do you think those two snakes had something qualitatively or quantitatively that the other 26 didn't have, which allowed them to survive?


    Ritchie said: "I fail to see the problem. It is correct that things that are fit tend to survive and the things which survive tend to be the fittest. Are you claiming this is untrue?"

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  11. Steve: Survival has nothing to do with fitness.

    Not always, but sometimes certainly.

    Natural Selection is the *correlation* betweeen variations in heritable traits and differential reproductive potential.

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  12. Steve -

    It is easy to imagine examples of animals surviving due to luck rather than suitability. And yes, I'm sure it happens. But it's perverse to imagine survival has nothing to do with fitness.

    Imagine a race. Ten people lined up ready to run. Generally, the fastest person will win. Yet it is easy to imagine scenarios where this is not the case - perhaps the fastest runner will stumble and fall, perhaps they will faint halfway down the track, or sprain their ankle, whatever. But it is reasonable to see that generally the fastest runner usually wins the race.

    I can't really see the logic in opposing the idea that those creatures best suited for survival will generally be the ones who survive.

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