I have previously read the site kindly submitted for discussion today and have recommended it (here on Hacker News, too, as I recall) before. This site is well worth a read. A comment asks for a recommendation of a book about macroevolution, transformation to new species among descendant organisms, and I can not only recommend two books, but also a free website. The website is 29+ Evidences for Macroevolution,[1] which I have recommended often to readers here on Hacker News. The books are Why Evolution Is True by Jerry Coyne[2] and The Greatest Show on Earth by Richard Dawkins.[3] Both books are very readable and interesting and well deserve your attention. There are other good recent books about evolution that help fill in the research findings that have occurred since you or I finished our formal schooling.[4]

[1] http://www.talkorigins.org/faqs/comdesc/

[2] http://www.amazon.com/Why-Evolution-True-Jerry-Coyne/dp/0143...

[3] http://www.amazon.com/The-Greatest-Show-Earth-Evolution/dp/1...

[4] http://www.amazon.com/The-Ancestors-Tale-Pilgrimage-Evolutio...

http://www.amazon.com/Your-Inner-Fish-Journey-3-5-Billion-Ye...

http://www.amazon.com/Endless-Forms-Most-Beautiful-Science/d...

http://www.amazon.com/Making-Fittest-Ultimate-Forensic-Evolu...

I like how the article succinctly discussed different possible causal mechanisms for losing a sense of smell that an individual formerly had as a marker for declining health and impending death.

This is especially interesting in view of the reduction of sense of smell over millions of years in the ancestral line of human beings. Before animals in the clade Primates developed trichromatic color vision, they distinguished fruits ripe enough to eat from fruits that were not mostly by smell. But after color vision improved, there was no longer selection pressure to maintain the sense of smell genes that gave the same information about food plants, and so random mutations gradually knocked out those genes. Comparative DNA analysis shows that human beings have descendant genes that were once used for accurate sense of many smells that human beings can no longer distinguish, but that sensory capacity was lost by genetic drift until lack of accurate sense of smell for many substances became fixed in the human population. A fascinating book that tells this story in more detail is The Making of the Fittest: DNA and the Ultimate Forensic Record of Evolution by Sean Carroll,[1] a very readable and enjoyable book about molecular biology studies and the evidence they provide for biological evolution.

[1] http://www.amazon.com/Making-Fittest-Ultimate-Forensic-Evolu...

"In the case of primate color vision, trichromacy based on the "new" M and L pigments (along with the S pigment) presumably conferred a selective advantage over dichromats in some environments. The colors of ripe fruit, for example, frequently contrast with the surrounding foliage, but dichromats are less able to see such contrast because they have low sensitivity to color differences in the red, yellow and green regions of the visual spectrum. An improved ability to identify edible fruit would likely aid the survival of individuals harboring the mutations that confer trichromacy and lead to the spread of those mutant genes in the population."

Sean Carroll has a very interesting discussion of the evolution of color vision in primates, and the consequent loss of selection pressure on many genes that develop sensitive sense of smell, in his book The Making of the Fittest.

http://www.amazon.com/Making-Fittest-Sean-Carroll/dp/0393330...