Category Archives: Biology

The rat in the can effect

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To find out more about the rat in the can effect, you can read this book: The Tangled Wing: Biological Constraints on the Human Spirit by Mel Konner, where I think it is described. Here, I will summarize it, in simplified form. If you seriously need to know about this in more detail, do more research and don’t rely entirely on what I say here. Continue reading The rat in the can effect


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Time itself as a resource that drives evolution

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Many of the key revolutions, or at least, overhauls, in biological thinking have come as a result of the broad realization that a thentofore identified variable is not simply background, but central and causative.

I’m sure everyone always thought, since first recognized, that if genes are important than good genes would be good. Great, even. But it took a while for Amotz Zahavi and some others to insert good genes into Darwin’s sexual selection as the cause of sometimes wild elaboration of traits, not a female aesthetic or mere runaway selection. Continue reading Time itself as a resource that drives evolution


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Great new kids’ science book

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Don’t Mess With Me: The Strange Lives of Venomous Sea Creatures by Paul Erickson is part of a series that is currently small but hopefully growing by Tilbury House. I previously reviewed One Iguana Two Iguanas (about iguanas).

Like the Iguana book, Erickson’s book for third through seventh graders (8-12 or so years of age) contains real, actual, science, evolutionary theory, and facts about nature, along with great pictures. The key message is that toxins exist because they provide an evolutionary advantage to those organisms that use them. Why are venomous animals so common in watery environments? Read the book to find out.

Species mentioned includ the blue-ringed octopi, stony corals, sea jellies, stonefish, lionfish, poison-fanged blennies, stingrays, cone snails, blind remipedes, fire urchins.

Highly recommended as a STEM present this holiday season.


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Educational Kids Gift: The Human Body by Smithsonian

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There is a new series of educational kits called Exploration Station, coming out in a few day. You can pre-order them. I’ll post about three of them, starting with Exploration Station: The Human Body.

Nicely packaged, the box itself will be useful even after the stuff inside is long gone.

The kids are designed for learning by kids six years and above, but I think they are ideal for third or fourth graders. All the kids follow a similar theme. There is one item that will end up on a bedroom shelf along with other toys like items. In this case, a make it yourself human skeleton one foot tall. There is a book on the subject, in this case, the human body. There is a large sheet of heavy duty laminated material and a set of stickers to stick on to it. In this case, it is a 13 by 18 inch poster with a depiction of the human body. In addition, this kit includes a set of flash cards about various aspects of the human body or physiology.

The back of the box. Note that this is for kids 6 and older. Eight or nine is an ideal age.

The science is good, the book is engaging, lots of words but also lots of pictures. The manipulable materials are fun and educational.

Comes with a great book at about 3rd or 4th grade reading level.

I think the kits were originally designated to be about $22, but the pre-order price is closer to $15 . I think they are worth the larger price, but the lower price is very nice.

Includes flash cards, a set of stickers, and a large body picture (not shown) to put the stickers on, and a small skeleton you can build yourself.

This is an ideal holiday gift for a kid in the right age range. It is not going to fill your space with a pile of useless crap, and it is not going to make a mess, or any noise. The educational value is high, and the quality is right in the range for an item of this price range. The only down side is that it is a little hard to wrap round things, but you’ll mange.

I recommend the Exploration Station: The Human Body for the kid in your life.


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People have big heads, but children have giant heads.

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A human is born with more neurons than they will have as adults. This is one of the main reasons that the size of the head of a child is not going to increase much as it grows. (Also, it is simply hard to make heads get bigger for various reasons, so it isn’t just humans that have large heads relative to body size when they are young.)

A person’s mass (weight) which roughly relates to volume goes up about 900% during growth. A person’s head circumference goes up about 35%. Big difference, even if you factor in the dimensional effect.

Try this: Find a small child. Preferably, your own, or if not, get permission. Show the child how you can touch your ear with the contralateral hand, by arching your arm over your head. Then, ask the child to try it. LOL.

This phenomenon, of head growth vs. body growth, comes up every time I teach about brain development, which I just did. And, it happens that right after doing that, I came across an interesting photograph. The photo is from a set of comparisons, putting an old family photo of one or more people when they were kids, to now, matching setting, clothing, props, body position, and facial expression.

When you do that, you see the head size thing really clearly in many photos. This one in particular shows it dramatically:

If you use the person’s right shoulder to help define her coronal plane, and visually project that onto the bricks, you can see that her head is close to three bricks tall in both photographs.

(I think the setting is not the same in both photos, by the way. Different bricks, different almost everything. But the person is the same, and that is what counts.)


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Whitey Bulger Dead, and the Trivers Willard Hypothesis

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The original version of this post was called “Whitey Bulger Caught, and the Trivers Willard Hypothesis.” A while after that, I wrote a post called “Whitey Bulger Convicted, and the Trivers Willard Hypothesis.” Today, it was announced that Whitey Bulger, Boston crime boss, is dead at 89. Thus, the new title.

Thumbnail image for 0470656662.jpgMost of you won’t know who Whitey Bulger is. He was for a while on the FBI’s ten most wanted list. He spent a lot of time overseas running from the Feds, but they eventually caught up with him, convicted him, and tossed him in jail.

Whitey was top dog in Boston’s Winter Hill gang. His brother was a Senator for the Commonwealth of Massachusetts, and served as Senate President for several years.

It is said that Whitey was an FBI informant, and that his handler, FBI Special Agent John Connolly, tipped Whitey off that he was about to be indicted on racketeering charges. No problem. Whitey had left stashes of cash in safe deposit boxes all around the world, in preparation for the day he had to go on the lam. So he took off in 1995. Special Agent Connolly spent several years on vacation in the stir.

I remember when Whitey disappeared, and ever since then, I’ve used him almost annually in lecture material describing the Trivers-Willard hypothesis. It goes like this:

Thumbnail image for 0470656662.jpgThe Trivers-Willard model (I prefer to call it a “model” rather than a “hypothesis” because it is not specific enough to really be a hypothesis … it’s a model that generates lots of hypotheses) states that selection should favor the ability to differentially bias investment in offspring by sex if the two sexes have differential variances in reproductive success, and if there is any way to predict offspring rank. That’s a bit thick, so it requires some examples and further explanation. Maybe a story about a mobster would help..

OK, so an example: Red deer (also known as Elk) give birth to one offspring (max) per year. Males compete for access to or to be chosen by females. So, only a small percentage of male red deer mate in a given year, a significant percentage may never mate at all, and a very small percentage sire many many little red deer. Male red deer have a high variance in reproductive success. If you tried to predict how many offspring a given randomly chosen male would have, knowing nothing at all, your best guess would be the average number of offspring red deer have in an average lifetime. But you would be wrong almost every time because the actual number is highly variable. Male red deer have high variance in RS.

Females, on the other hand, have a pretty standard number of offspring. There is not much competition among them, they can always find a male to mate with, etc. If you needed to guess how many offspring a particular randomly chosen female red deer would have in a life time, you could guess the average, and you would be right on or very close. Female red deer have low variance in RS.

So, male and female red deer have differential variance in RS. Males high, females low.

If a female red deer could somehow “predict” the likelihood of her offspring getting to mate, i.e., if she could tell if any offspring she had in the present year (male or female) would be average vs. high ranking, then selection should favor the evolution of a mechanism to actually give birth to the appropriate sex offspring (thus biasing investment in one sex or the other). It turns out that she can. A female red deer that is herself average or lower-quality (thin, ill, injured) is likely to give birth to an offspring that will be either low ranking or average. But if the mother-to-be red deer is high ranking, she is likely to give birth to an individual who will grow up to be high ranking.

Under these conditions, she should have a female offspring if she’s average or low ranking, but a male if she’s high ranking. And that, it turns out, is what red deer actually do.

That should be clear. But in case it isn’t, let’s take it down do real life, and bring in the gangsters.

You check the mail this afternoon, and there is a letter from a law firm you have never heard of. It says that your Great Aunt Tillie (whom you’ve also never heard of) just died, and left you with $1,000 in her will. The check is enclosed.

Thumbnail image for 0470656662.jpgThis may or may not be a recent photograph of a male red deer. Holy crap. Found money! What are you going to do with it? So you and your close advisors (your roommates, your cat, etc.) discuss it and you narrow it down to two choices. Choice A and Choice B.

Choice A is to go to your broker and buy $1000 worth of a nice, relatively safe mutual fund. The fund will buy and sell reliable blue chip stocks, thus spreading the risk over several companies, and over time you can expect to get a return of 50 bucks a years, easy.

Choice B is to buy 1000 one dollar lottery tickets. Your chances of winning are slim, but if you do, you will win 87 million dollars.

So, what do you do? The obvious sane choice is to buy the mutual fund.

But what if your cousin is Whitey Bulger? Whitey Bulger, as head of the Winter Hill Gang, is said to have owned the director of the Commonwealth Lottery agency.The connection between Whitey Bulger and the Lottery has never been proven. They don’t have a shred of evidence. He was, however, indicted for 21 counts of RICO-Murder. It is said that one of the things that tipped off authorities about this is that some of his relatives were winning the lottery a little more often than they should have. So, say your cousin is Whitey Bulger, and last time you saw him (at a family wedding) he told you … “hey, if you ever want to take a “chance” on the lottery, let me know … I can make that work for you…”

So now, you have two choices.

Choice A: Invest in a mutual fund and gain a return of 50 bucks a year (that’s dollars, not elk); and

Choice B: Buy 1000 PowerBall tickets and have a great deal of certainty of winning 87 million dollars.

What would you do?

In case it isn’t already clear. the baby male elk is a lottery ticket, the baby female elk is a mutual fund, but the female can guess pretty accurately if the lotter ticket (male offspring) will pay off. Because the elk’s cousin is Whitey Bulger. See?


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Amazing Book On Amazing Arachnids

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I am strongly recommending Amazing Arachnids by Jillian Cowles.

This book is in line to win the Greg Laden’s Blog Science Book of the Year.

Sample text, to give a taste of the science
It looks like a high quality, almost coffee table like, book on the arachnids, things like mites and spiders and such. But that is only what it appears to be on the surface. Just below the surface, it is a compendium of evolutionary amazingness, a detailed description of the photogenic history, behavioral biology, and co-evolution of plants and animals, with almost all the protagonists in the numerous loosely connected stories being one sort or another of amazing arachnid.

Geographically, the book focuses on the arid American Southwest. This allows the author to be quasi-comprehensive in coverage of species (about 300 from among 11 orders). It also allows the author to tell the story of these critters as a story, with interconnected features of evolution and ecology. This is literary hard core science, with great illustrations (about 750 color photos, and other illustrations).

Because of the US SW focus, it might be a better purchase for people living in just that area. But as is the case with a handful of other nature-oriented books, like the The New Neotropical Companion, the science content and overall interest of the book transcends geography. You’re not really going to want to get that close to these arachnids anyway….

This is a very good book. You will learn things, even if you already know a lot about arachnids.

The author is a clinical microbiologists and photographer.


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The Origin of Life and Life on Other Planets

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The Origin of Life and Life on Other Planets

Several parallel discussions inspire me to write this post partly in the hope that you will chime in.

The chance of life elsewhere in the universe just went to near zero. Or did it?

Continue reading The Origin of Life and Life on Other Planets


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How To Reconcile the Insanity of Cladism with the Order and Beauty of the Linnaean System

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Knowledge is knowing that a bird is a dinosaur. Wisdom is not charging people extra to see your reconstituted Jurassic Park style dinosaur zoo when all you’ve got is a barn full of chickens.

To really understand the meaning of this, please read my brand new essay at 10,000 birds, here:

If Birds are Dinosaurs than I’m a Monkey’s Uncle

… which is part of the Come At Me series of fantastic posts on that site.


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Yet Another South American Alien Turns Out To Be Human

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But a very interesting human. A human being six inches tall (if standing), with only 12 sets of ribs, about 7 years old at the time of death. Did I mention six inches tall? New research on the so called “Atacama humanoid” (not an alien, just a human) shows a wide range of interesting genetic differences, according to a just published paper. Continue reading Yet Another South American Alien Turns Out To Be Human


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Sexual Selection Up To Date: A Taste for the Beautiful

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A Taste for the Beautiful: The Evolution of Attraction is a popular science book written by an actual expert on the field, addressing the ways in which the world of animals is shaped by sexual selection.

One of Darwin’s major contributions to the panoply of theoretical and observational work we call “evolution” was to recognize, describe, and model sexual selection. Continue reading Sexual Selection Up To Date: A Taste for the Beautiful


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Darwin Quotes, Assembled

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From Janet Browne, the author of Charles Darwin: A Biography, Vol. 1 – Voyaging and other works about Charles Dawin, The Quotable Darwin.

Quotes by Charles Darwin are not just the stuff of memes. Even the fake quotes. They can be the center of long arguments, or at least, they can significantly augment the arguments. For example, did you know that while Darwin never used the term “missing link” he did talk about missing links quite a bit, missing links are central to his thinking about evolution, and all those writers of today who claim that we must never speak of missing links are misguided? Continue reading Darwin Quotes, Assembled


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Is There Evidence of Life On Mars?

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At present, the evidence suggests that life may have existed in the past on Mars, or not. However, the scientific consensus is that we assume life never arose on Mars, and will continue to do so until evidence pops out and bites us in the mass spectrometer.

There is no evidence of life on Mars right now. Continue reading Is There Evidence of Life On Mars?


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