Evolution explained by a 7-year-old

by philg

On an evening stroll with a 7-year-old, following a discussion of why dogs’ night vision is better than ours, she pointed out that “We’re descended from monkeys. What do we share with monkeys? Two legs. Two arms. The love for bananas.”

9 thoughts on “Evolution explained by a 7-year-old”

  1. That’s true. Color vision is mostly pointless for a predator since it is cheap for a prey animal to color itself the same shade as it’s surroundings. What a prey can’t change is it’s shape, at least it can’t change it without paying a significant performance penalty.

    So if something is colored, it’s because it WANTS to be seen. It wants to say it’s ripe, or poisonous, or a good mate, or whatever. It wants to send a message. And if an animal has color vision it’s usually because it has a need to receive such messages.

  2. Americans think life was created by the government in 7 days. Dogs had a better lobbying group than humans.

  3. Explanation that living thing has a trait because it needs it is not Darwinian evolution. Darwinian evolution explanation is that living thing prospered because it accidentally mutated to acquire the trait that accidentally helped it survive.

  4. Darwin thought acquired traits were passed on to some extent, “lamarckism” in essence. So limiting the definition of “Darwinian Evolution” to selection pressure on mutations is somewhat incorrect.

    Plenty of experimental evidence now shows this to be the case. The most fascinating demonstration I know of is that rats taught to run mazes clearly pass on better maze running ability to their offspring as an acquired trait.

    The model of evolution that limits the process to mutation is clearly wrong.

  5. @

    One would have thought that Lysenko was dead, but apparently not — его дело живет и побеждает !

    There has been no rat maze memory transfer experiment with successful replication. The closest I know of is described by Frank et al. and the alleged “memory transfer” is explained by the induced stress (http://science.sciencemag.org/content/169/3943/399) rather than by epigenetics.

    The recent much modest parental olfactory experience transfer experiment by Ressler & Dias was criticized by Francis (https://www.ncbi.nlm.nih.gov/pubmed/25316784) whose statistical argument I find convincing.

    There does not appear to be a known reliable mechanism for epigenetic transfer — almost all epigenetic marks are reset to their standard values in a brand new embryo and thus lost in the progeny. It seems the only real case case of an incomplete DNA reset is found in agouti mice (in mammals).

    The model of evolution that limits the process to mutation is mostly right according to what is known today.

  6. @Ivan: Persistent epigenetic differences associated with prenatal exposure to famine in humans

    http://www.pnas.org/content/105/44/17046.long

    >The model of evolution that limits the
    >process to mutation is mostly
    >right according to what is known today.

    I don’t think the pnas paper contradicts this statement, but that doesn’t mean that epigenetics is unimportant in understanding human development.

  7. @Neal

    I am familiar with both the Dutch famine, as well as the Siege of Leningrad and the Big Leap Forward research works.

    With respect to intergenerational effects (“epigenetics”):

    “In the aggregate, the reported findings on maternal prenatal famine exposure and birth size in a mother’s own offspring appear to be inconclusive” (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3857581/)

    My personal ancestral history whose various branches went through such environmental shocks like the revolution, two famines (much harsher than the Dutch one), German occupation, forced labor camps seems to suggest that the said shocks had zero impact on the offsprings

  9. 100% Ivan. Same here on famines. Also ancestral skillsets. No clue about skills that were common among several generations of my ancestors who kept same occupation but whom I did not have a chance to learn from. No matter how much my dog’s parents and grandparents were taught to shake paw trick and forcibly kept out of the water my new pup had to be taught to shake paw but braved stream and even ocean waves without any prompt – genetic selection shows, learned skills passing not so much. Can not change a specie by teaching, only by genome selection, random mutation or genetic engineering.

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