This post was originally published in “Download the Universe,” a multi-author blog about science ebooks edited by Carl Zimmer.
Sea Change. By Steve Ringman and Craig Welch. Published by Seattle Times.
The Course of Their Lives. By Mark Johnson and Rick Wood. Published by Milwaukee Journal-Sentinel.
Reviewed by Carl Zimmer
October 24, 2013
Last week, scientists published a study of five 1.8 million-year-old hominid fossils. They may reveal profound lessons about a crucial chapter in our evolution: how our ancestors changed from bipedal apes to a more human-like lineage–in other words, the emergence of our genus, Homo. So what name do we give these skulls? What species do they belong to? It’s no simple matter naming our hominid ancestors, and that difficulty tells us something intriguing about their biology. And that’s the subject of my “Matter” column this week in the New York Times. Check it out.
Continue reading “Naming Our Ancestors: My New Column for the New York Times”
A simple question deserves a simple answer. How many cells are in your body?
Unfortunately, your cells can’t fill out census forms, so they can’t tell you themselves. And while it’s easy enough to look through a microscope and count off certain types of cells, this method isn’t practical either. Some types of cells are easy to spot, while others–such as tangled neurons–weave themselves up into obscurity. Even if you could count ten cells each second, it would take you tens of thousands of years to finish counting. Plus, there would be certain logistical problems you’d encounter along the way to counting all the cells in your body–for example, chopping your own body up into tiny patches for microscopic viewing.
For now, the best we can hope for is a study published recenty in Annals of Human Biology, entitled, with admirable clarity, “An Estimation of the Number of Cells in the Human Body.”
Genetic testing for individual disorders was once the brave new world, but now it’s a familiar routine of having a baby. But what about looking over a baby’s entire genome? As the price for sequencing DNA crashes, it’s becoming a real possibility. At Slate, I write a new study in which the genomes of 240 babies will be sequenced, and researchers will see whether how that avalanche of data affects their medical care. Check it out.
Continue reading “Genomes From Birth: My New Piece for Slate”
Mimicry is one of the eeriest feats of evolution. An insect doesn’t know what a leaf looks like, and yet some species have evolved to resemble leaves down to the finest details. Their mimicry emerges from the ruthless cycle of evolution. The ancestors of leaf insects produced lots of genetic variation, thanks to mutations and mating. Some of that variation affected how they looked. Birds have been feasting on the insects for millions of years, and their victims have tended to be the easiest ones for them to see against their leafy background. The insects that were harder tended to survive and reproduce. Over time, evolution acted like a sculptor, turning an ordinary insect body into a shape that blended in with the surrounding leaves.
But the mimicry of leaf insects, as cool as it may be, is simple stuff compared to what’s evolved in other species. Continue reading “Nature’s Double Con”