Yucatan
Aggressive African bees were accidentally released in Brazil in 1957. As "killer bees" spread northward, David Roubik, staff scientist at the Smithsonian Tropical Research Institute, began a 17-year study that revealed that Africanized bees caused less damage to native bees than changes in the weather and may have increased the availability of their food plants.
They gracefully swim through the complete darkness of submarine caves, constantly on the lookout for prey. Instead of eyes, predatory crustaceans of the class Remipedia rely on long antennae which search the lightless void in all directions. Like some type of science fiction monster, their head is equipped with powerful prehensile limbs and poisonous fangs.
Without the process of domestication, humans would still be hunters and gatherers, and modern civilization would look very different. Fortunately, for all of us who do not relish the thought of spending our days searching for nuts and berries, early civilizations successfully cultivated many species of animals and plants found in their surroundings.
Without the process of domestication, humans would still be hunters and gatherers, and modern civilization would look very different. Fortunately, for all of us who do not relish the thought of spending our days searching for nuts and berries, early civilizations successfully cultivated many species of animals and plants found in their surroundings.
MADISON -- The adage that dead men tell no tales has long been disproved by archaeology.
The Cozumel Thrasher (Toxostoma guttatum), a bird not seen or recorded by scientists for close to a decade and thought by some to have gone extinct, was sighted last month by a team of field biologists, American Bird Conservancy and Conservation International announced today. Its rediscovery immediately makes it the single most threatened bird in Mexico. The Cozumel Thrasher, an endemic bird found only on the island of Cozumel off the Yucatan Peninsula in Mexico, appears to have experienced a precipitous decline in 1988 after Hurricane Gilbert tore through the island.
From Canada to Central America, the many grandeurs of North America's diverse topography star in a just-released high-resolution map from NASA's Shuttle Radar Topography Mission. But a relatively obscure feature, all but hidden in the flat limestone plateau of Mexico's Yucatan Peninsula, is what emerges as the initial showstopper from the mission's first released continental data set. The existence of the impact crater known as Chicxulub (Chik-sah-loob) was first proposed in 1980. In the 1990s, satellite data and ground studies allowed it to gain prominence among many scientists as the long sought-after "smoking gun" responsible for the demise of the dinosaurs and more than 70 percent of Earth's living species 65 million years ago. Now, the Shuttle Radar Topography Mission has provided the most telling visible evidence to date of a 180-kilometer (112-mile) wide, 900-meter (3,000-foot) deep impact crater, the result of a collision with a giant comet or asteroid on one of Earth's all-time worst days.
