Tag: Darwin

On the Origin of Species

Perhaps the key reason for the profound influence of Darwin’s “On the Origin of Species” is that it’s such a well written and well reasoned argument based on years of study. It is a wonderful example of how science should be done, and how it should be presented. In the past I’ve had my middle schoolers try to translate sections of Darwin’s writing into plainer, more modern English, with some very good results. They pick up a lot of vocabulary, and are introduced to longer, more complex sentences that are, however, clearly written.

Diagram and notes on the bird species P.Nanus from The Zoology of the Voyage of H.M.S. Beagle, Part 3: Birds by J. Gould and G.R. Gray (edited by C.Darwin). Image via Darwin Online.

The text of “On the Origin of Species” is available for free from the Gutenberg library. Images of the original document can be found (also for free) at the UK website, Darwin Online (which also includes the Darwin’s annotated copy). Darwin Online also hosts lot of Darwin’s other works, as well as notes of the other scientists on The Beagle, among which is included some wonderful scientific diagrams.

This year, I’m going to have the middle schoolers read the introduction, while the honors environmental science students will read selected chapters and present to the class — this will be their off-block assignment.

Diagram of the fish Cofsyphus Darwini by L. Jenyns in The Zoology of the Voyage of H.M.S. Beagle, Part 4: Fish (edited by C.Darwin). Image via Darwin Online.. .

Selective breeding of foxes

A silver fox. Image by Zefram via Wikimedia Commons.

Evan Ratliff has an excellent article that ties well into our discussions of evolution. It’s on the breeding of foxes to make them want human companionship, much the same way wolves were domesticated.

… researchers … gathered up 130 foxes from fur farms. They then began breeding them with the goal of re-creating the evolution of wolves into dogs, a transformation that began more than 15,000 years ago.

— Ratliff (2011), in National Geographic, Taming the Wild

Wild boar (top) versus a domesticated pig (bottom). Note the floppier ears, a trait common to domesticated animals. Figure from Darwin (1968).

It worked remarkably well, and not just with foxes, but with rats and mink as well.

The scientist in charge, Dmitry Belyaev, was looking into something that Darwin observed in 1868: domesticated animals are smaller, with floppier ears and curlier tails, than their untamed ancestors.

In terms that we’ve studied, domesticated animals all have similar physical characteristics (phenotype) and Belyaev wanted to find the genotype. His theory is that there is:

… a collection of genes that conferred a propensity to tameness—a genotype that the foxes perhaps shared with any species that could be domesticated.

— Ratliff (2011), in National Geographic, Taming the Wild