Snippets From Science

• Anthropologists assume that modern man evolved by branching from an ancestral type that also gave rise to chimps and other primates of today. How is it that our ancestors developed larger brains than other primates? Scientists have long theorized that their diets began to include meat, which would be necessary for rapid brain development (although the brain makes up about 2 percent of the body’s mass, it consumes 20 percent of the body’s energy in order to grow and function properly). But this was just a theory, because there was no archaeological evidence for it. Recently, however, a research team in Kenya dug about 25 feet below the surface of what had been a grassland two million years ago, about the time our ancestors (called Homo erectus) appeared to take on distinctive human qualities. Analysis of soil and bits of fossils discovered in the Kenyan dig showed that our ancestors were eating crocodiles, hippopotami, and turtles, along with their usual vegetarian diet. Probably they scavenged flesh from dead or dying animals and ate it raw (fire was discovered later). The flesh of these animals is rich in the fatty acids and proteins necessary for brain growth. (Levin et al, 2010, Proc. National Academy of Sciences, June 1; Michael Anft, Brain in the News, Oct. 2010)

• Although plastics are indispensible in packaging, they take decades to degrade in landfills. Researchers at Case Western Reserve U. are experimenting with chemically treated curds (the protein part of milk) to create a new material that is equivalent in strength and stiffness to polystyrene, a modern packaging plastic that is practically indestructible. Preliminary studies indicate that 20 percent of this new “plastic” degrades in a landfill in 18 days, and disappears completely in a short period of time. (The Economist, Oct. 30, 2010)

• Some scientists claim that 70 – 90 percent of disease risks are related to environmental exposures. All living things, from amoebae to man, are chemical machines that can be influenced by environment. Over and over again, our internal chemical environment has been shown to be affected by radiation, stress, life style, infections, drugs, diet, and pollution. Scientists are undertaking new ways to assess how environmental factors affect the risk of developing chronic disease. (Science, “Environment and Disease Risks,” Oct. 22, 2010)

• Just for the Fun of It: The fastest fish? The Sailfish can reach speeds of 68 mph. Fastest bird: the Spine-tailed Swift can cruise at 106 mph, and a Peregrine Falcon has been clocked at over 200 mph in a dive for a prey. Cheetahs can attain speeds of about 70 mph, and they could easily run down the fastest reptile, the Spiny-Tailed Iguana, which can reach 21 mph. But the fastest human (Husain Bolt, world record holder in the 100 meter dash) could outrun this iguana, for his speed record is 27 mph. We could all catch the fastest insect, for the cockroach’s top speed is only 3.36 mph.

• Insects have evolved many ways to defend themselves from predators. Two classes of defensive chemicals are produced by insects. Class I chemicals injure, sting, poison, or drug predators. Class II chemicals are noxious to predators because of their repulsive odor or taste. Some insects produce both kinds of chemicals, one painful or harmful and the other either stinks or leaves a bad taste in a predator. Thus predators may soon learn to associate a given odor or bad taste to a painful experience and avoid such prey. (Gullan and Cranston, The Insects, 2005, Blackwell Publishing)