NOTES AND LINKS

I started this in the limited time I had before I delivered the talk: I will add to it over time. The latest addition was on March 29, 2006. There are sections on

Geological Time

Evolution

I put together a quirky collection of links on evolution for my students in my course "History of Life". This is not meant as a systematic introduction to evolution. Some of my own essays are ten years old, and you might be better to get a more modern book from the library. However, some of the links are superb. Some of them also appear in the sections below. Browse and have fun! Here is the page.

Birds, Dinosaurs, and Feathers

Down feathers and/or display feathers on theropod dinosaurs

  • Brooding Eggs.
    A block of rock collected in Mongolia in 1993 turned out to contain an adult Oviraptor that had been buried in a sandstorm while it was crouched over a nest of Oviraptor eggs. The only reasonable explanation of this find is that the dinosaur was brooding its eggs, just as most living birds do. By 1996, three of the seven known Oviraptor adults had been discovered on or near nests. It is very unlikely that Oviraptor was cold-blooded! However, it becomes a matter of judgment how far to extend Oviraptor's body temperature to other dinosaurs.

    While we are talking about dinosaur embryos inside dinosaur eggs, let's ask how they compare to bird embryos inside bird eggs. Here is an awesome site that shows an emu embryo inside an emu egg. University of Texas CT lab.

  • Dinosaur parental care.
    From October 2004. The new specimen is another astounding fossil from the Yixian Formation of the early Cretaceous of China. It is a slab of rock with an adult of the small ornithischian dinosaur Psittacosaurus and 34 youngsters. All the skeletons are remarkably complete and undisturbed. All the young dinosaurs are the same size, and all in the same body attitude: right side up, in a crouching position with the limbs folded under them, but the heads raised a little. The adult is in the same attitude. The adult and the youngsters were obviously killed and buried in the same disaster. The authors speculate that the disaster could have been smothering by volcanic debris; entrapment down a burrow; or flooding of a nest or natural hollow. There is no obvious volcanic ash, so any volcanic disaster was not a direct eruption. This is an absolutely compelling case of adult care for juvenile dinosaurs.The paper is in Nature, so it won't be on the Web: Meng, Q., et al. 2004. Parental care in an ornithischian dinosaur. Nature 431: 145­146. But check this story in National Geographic News

    More links

    Crocodiles

    The Evolution of Whales

    More Answers to Questions Asked at the Lecture

    1. Looking for dinosaurs in Mongolia

    2. Darwinian Doctors To do.

    3. Can a single mutation spread through a population and species? The simple answer is yes. I have tried to find actual examples.
      1. Lactase. All babies can digest milk, human milk at least. They have a hormone called lactase that breaks down the lactose (sugar) in milk. But most humans lose that capability early in life: after all, why should humans have evolved to drink milk after they are weaned? "Lactose intolerance" occurs when there is no lactase to break down the milk, and people get stomach upsets and allergic-type reactions. Originally, all adult humans would have been lactose intolerant.

        Once humans domesticated animals, milk became theoretically available from cows (including yaks), sheep and goats, camels, reindeer, and maybe other species. But it wasn't truly available except to babies, because adults did not produce lactase.

        Now here comes the mutation: a mutation that maintains lactase production after weaning. It's a very simple mutation in theory, because it doesn't produce any new biochemistry, it simply extends the time over which the "baby" biochemistry for milk digestion works.

        If there's plenty of "adult" food, a weaned baby will eat that. But in bad times, a child can drink milk and survive, whereas the neighbor child with lactose intolerance would not have that option and might die of malnutrition. The mutation that prolongs lactase action would not even be noticed in the population except in bad times, because it does no harm; yet in bad times, it is a very powerful survival mutation.

        The mutation that prolongs lactase action is mainly possessed by people in Northern Eurasia, especially in Northwest Europe. They had herds of animals before they planted crops. The mutation must have spread widely among those people, while it did not among the farmers in better climates. At least in California, Asian-Americans are more prone to lactose intolerance than other groups, but it occurs in all groups to some extent. In our society today there are substitutes such as soy "milk", so it's not a nutritional issue, and it's not likely to be playing a part in natural selection as it once did.

        Web sites to follow...

      2. Malaria-resistant mutations. (To do.)

    The "Other Side"

    There is no "other side" if we are talking about science. But we're not, are we? The "monster in the closet" is faith-based assertion.

    This is the only part of my lecture in which I used any "script". My notes to myself read as follows.

    How does all this (the information I presented) related to Intelligent Design (ID) and to creationism?

    ID proponents argue that the world is too complex for us to understand and explain, therefore we have to admit that there must have been some sort of "Creator". But let's look back at 1406, six hundred years ago. What would an ID argument have sounded like at that time? The ID argument would have included weather, tides, disease, eclipses, fire, magnetism, volcanic eruptions, and earthquakes. Well, we understand and explain all those natural phenomena today. Now, it seems, we're only left (for ID folks) with biology and especially with evolution.

    We solved all those other issues by saying "it's NOT too complex to understand if we simply look at it carefully." And the same applies today to biology. In fact, we know more than the average person realizes: it's just that you need a lot of education in biology to appreciate just how much we do know and understand. It doesn't take a formal degree (I don't have a biology degree), but it does take a commitment to learn.

    The ID argument simply does not work.

    Even the creationists don't like ID. Their criticism is that ID presents only a vague concept of a creator, whereas the creationists believe that the Bible tells us precisely who that Creator is, and precisely what and when he did. Nevertheless, creationists openly recognize that ID is distracting the world of science from paying too much attention to them: this is part of the "wedge effect" that Maureen Stanton mentioned. But the creationists use another analogy: the ID movement might allow anti-scientific ideas to get the camel's nose into the tent!

    Now for the creationist argument. I think it must be very hard to be a creationist. Once you are tied (by faith) to a belief in the literal truth of the Bible, you are committed, on pain of burning in fire forever, to

    This leads not only to the creationist refusal to accept evolutionary biology, but also to a particular creationist ecology for the Garden of Eden, and a creationist cosmology, creationist astronomy, creationist geology, creationist archaeology, and creationist anthropology, and an acceptance that the laws of physics can change and in fact have changed. It's a pretty complete denial of the world view built up over thousands of years of investigating the world around us, using observation and logic: the scientific world view.

    Overall, I'm perfectly at ease with people practising their religion in their homes and their churches. But the particular view of one religious group does not belong in the science classroom.

    Now I didn't make up my characterization of ID and creationism. Here are some Web links to show you the sort of thing that's out there: overtly faith-based, with science addressed only with negative (and poorly constructed) criticisms. Every reader should look through it, however, just to see what science educators are facing.

    Last updated, Thursday March 29, 2006.