Category Archives: Biology

Starfish Anus, Sea-Star Butt

During a hectic visit to the California Academy Of Sciences in San Francisco’s Golden Gate Park, I took this picture of my sister petting a starfish –excuse me, a sea star. (The Steinhart Aquarium –the aquatic section of the Academy– exhibits a tide pool where animals are available for gentle handling.)  Only later in the day did I inform my sister that she had been fondling the sea-star’s anus.  She asked my why I hadn’t informed her at the time.  I suppose I just assumed everyone knows basic sea-star anatomy –that the anus is dorsally located, at the center of the disc. She wasn’t too perturbed. No harm done.  But a good reason not to forget the hand sanitizer.  And it does go to show that invertebrates are not given their due.

Just an afterthought, but I think Starfish Anus would be an excellent name for a rock band.

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Dandelion Sex, Or The Lack Thereof

Dandelion (From Wikipedia)

Dandelion (From Wikipedia)

I’ve just finished reading Frogs, Flies, & Dandelions: the making of species by biologist Menno Schilthuizen –an engaging and informative book on species formation. Here’s a little taste of what I learned; it illustrates that genetics isn’t perfect, and evolution is beautifully adaptive.

Historically, the common dandelion, that ubiquitous and irritating weed found in gardens and fields throughout North America and Europe, has been a puzzle to botanists. For a long time, no one was sure how many species existed. In the 1700’s, Carolus Linnaeus said only one; in the 20th century, Scandinavian botanists claimed more than two-thousands existed. But with DNA testing, came the answer. Many dandelions are, in fact, clones. In place of normal sexual reproduction with two sets of chromosomes being divided into sex cells, the ovules and pollen, some dandelions reproduce by parthenogenesis, or virgin birth, because at one point in their history they mutated into having three sets of chromosomes, a number which is sexually indivisible. The mutant dandelions instead produce unfertilized –but still viable– seeds, each with a triple set of chromosomes –in other words, a clone.

What’s most illuminating is that the same mutation has popped up several times. So there are several strains with triple chromosomes, all sexually isolated from one another because they can only reproduce by cloning themselves. But it gets better; the clones still produce pollen, except it is completely sterile. Only in the light of evolution does this sordid asexual tale make sense. Why waste the time and energy producing “irregular pollen” if it’s never going to be used? Perhaps god takes a sadistic pleasure in irritating people’s allergies. Or he’s invested heavily in big pharmaceuticals. If so, I hope he had Bernie Madoff sitting on his nest egg.

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Filed under Biology, Evolution, Science

Watch Out For Bird Brains

I’ve always thought that the observational powers of birds could be harnessed for good or evil. Perhaps the nuthatch republicans would like to place a tiny camera on a yellow-shouldered Amazon parrot’s head to spy on Venezuela’s leader, Hugo Chavez. They’re obsessed with his socialist activities, for some reason. Or the paparazzi would like to use little Tits to spy on bigger tits.

There are so many birds around us on a daily basis, we most often tune out their chatter. What a shame. I’ve noticed over twenty-five bird species in my own backyard while paying a minimum of attention over the years. On any given day there must be at least a dozen. I just hope none of them have been watching me too closely. Sometimes I have their cousins over for dinner.

Check out David Attenborough on YouTube. His series on the Life of Birds is brilliant and educational. The Bowerbirds are my favorite.

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Filed under Biology, Science

Genome Size and Complexity

the groups in this figure are arranged along made-up "scala naturae" to emphasize the lack of relationship between genome size and intuitive notions of organismal complexity -- please do not construe this figure as an endorsement of a progressionist view of evolution!).

(Note: the groups in this figure are arranged along made-up “scala naturae” to emphasize the lack of relationship between genome size and intuitive notions of organismal complexity — please do not construe this figure as an endorsement of a progressionist view of evolution!).

The chart above and note are from genomesize.com

As the note says, the bars in the chart indicate ranges of genome size. The measurements are given as a C-value, which here is a measure of weight in picograms. As we can see, genome size and complexity do not go hand in hand. Salamanders, flatworms, and algae are just a few of the groups which have members with genomes sizes larger than that of the mammals. Et tu, Chondrichthyes? Members of the protozoa have the largest. Isn’t it bad enough that humans have to deal with penis envy, now this? If there is a creator, he has an “inordinate fondness” for amoebae. All that sexy amoebic swaying and oozing is what did it. It’s a damn popularity contest. The swimsuit contest lost us the most points; the amoeba slipped out of its top, showed some membrane, and won the day.

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Filed under Biology, Intelligent Design

Deepest Living Fish Found

If you occasionally peruse the New Scientist in book stores or on newsstands, or just enjoy a dose of easy-to-digest science, check out the magazine’s YouTube channel. My favorite of their latest videos is about the deepest living fish ever found. These little buggers, called Snailfish, show all the characteristics of a deep sea existence. For one, their tail musculature is greatly reduced, and their oversized pectoral fins provide most of the locomotion. Living in the deep, these fish don’t have to deal with strong wave action or fast currents. And it’s not surprising that their shallower-water cousins have more powerful tails, and a lot more body pigmentation.

God, the creator, must be a real lazy bastard. He basically took the same fish and pawned it off as two separate creations. I feel cheated.

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Fish Fingers In Fish Farming

Fish farming has often been touted as the solution to our fishery problems. Proponents say that we can grow our own fish and give wild fish populations a break. It sounds good on paper. But as usual, reality doesn’t match expectations. Fish, even caged ones, need to be fed. Carnivorous fish require fish meal (ground up fish) in their diets. And humans are not overly enthusiastic about herbivorous fish as a food source. Fish markets sell Tilapia, a species which can be grown on a diet of algae, but humans still have a major hankering for Wild Salmon and Sea Bass.

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Filed under Biology, Science

The Snake In The Garden Of Eden With A Squirrel

Gopher Snake

Evolution is truly fascinating. There’s a video of a squirrel tap dancing around a snake and bravely nibbling on its body. The quality isn’t that great, so the identity of the snake is a bit of a mystery. It acts like a rattlesnake, but it doesn’t have the arrow shaped head, which is characteristic of the viper family. However, non-venomous gopher snakes mimic the behavior of rattlers to scare away predators. And on top of that, even if it were a rattlesnake, the squirrel has a genetic advantage. Adult squirrels have a partial immunity to rattlesnake venom. They can take several hits of venom and still survive. They even have a physiological mechanism to heat up their tails, which fools with the snake’s heat sensing ability. The moral of the story is that our human preconceptions about what’s going on in the natural world are often wrong.

www.TheDarwinReport.com

         

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Filed under Biology, Uncategorized