INSTINCTUAL BEHAVIOR AROSE

White-crowned Sparrow, Zonotrichia leucophrys; image by Frank Schulenburg, via Wikimedia Commons

When a White-crowned Sparrows such as that at the right is hatched and kept where no kind of birdsong ever can be heard, at about 100 days of age the bird begins producing song in which an experienced birder can hear the basic features of a wild White-crowned Sparrow's song. The song isn't nearly as rich and pleasant to hear as that produced by wild birds, but it's clear that White-crowned Sparrows are born predisposed to sing the song of their ancestors.

Similarly, when a Canvasback duckling has just hatched in an incubator, immediately after drying off, it can walk, swim, and, if necessary, dive below the water's surface.

Earth's living things are born with strings of commands expressed in terms of patterns of chemical nucleotides, or bases, on the DNA molecule in cell nuclei. The four base pairs written as A,T,C and G represent the chemical compounds adenine, thymine, cytosine and guanine. An example of code is shown below:

genetic code example; image courtesy of Madeleine Price Ball via Wikimedia Commons

How do the ancestors' song, the ability to walk, swim, dive, and many, many other complex behaviors make their ways into and out of the one-celled zygote stage, which all the Earth's sexually reproducing organisms begin as, except bacteria?

The information passes by way of patterns of chemical compounds arranged along long, spiraling molecules of DNA in the cell nuclei of the parents' sperm and ova, as sketched above.

If we are to use the term "miraculous," then surely the leap of song, walk, swim and dive from a DNA molecule into an organism living a normal life on Earth, is miraculous.

• The Khan Academy's Innate Behaviors page.
• Wikipedia's Instinct page.
• Scientific American article Free Will versus the Programmed Brain.
• YouTube video on How we are programmed at birth.