Monday, February 19, 2007
Evolution
In biology, evolution is the change in the heritable traits of a population over succeeding generations, as determined by shifts in the allele frequencies of genes. Through the course of time, this process results in the origin of new species from existing ones . All contemporary organisms are related to each other through regular descent, the products of cumulative evolutionary changes over billions of years. Evolution is the source of the huge diversity of extant and extinct life on Earth.
The basic mechanisms that produce evolutionary change are natural selection and genetic drift; these two mechanisms act on the genetic variation created by transformation, genetic recombination and gene flow. Natural selection is the process by which individual organisms with favorable traits are more likely to survive and reproduce. If those traits are heritable, they are passed to succeeding generations, with the result that beneficial heritable traits become more common in the next generation. Given enough time, this inactive process can result in varied adaptations to changing environmental conditions.
Monday, February 12, 2007
Religion
Religion is a system of social coherence based on a common group of beliefs concerning an object, person, unseen or imaginary being, or system of thought considered to be supernatural, sacred, divine or highest truth, and the moral codes, practices, values, institutions, and rituals associated with such belief or system of thought. It is sometimes used interchangeably with "faith" or "belief system", but is more socially defined than that of personal convictions.
The development of religion has taken many forms in various cultures. "Organized religion" generally refers to an organization of people supporting the exercise of some religion with a prescribed set of beliefs, often taking the form of a legal entity . Other religions believe in personal revelation and responsibility.There are many definitions of religion, and most have struggled to avoid an overly sharp definition on the one hand, and meaningless generalities on the other. Some have tried to use formalistic, doctrinal definitions and others have tried to use experiential, emotive, intuitive, valuational and ethical factors.
Friday, February 02, 2007
Tornado
A tornado is a violently rotating column of air which is in contact with both a cumulonimbus cloud base and the surface of the earth. Tornadoes can come in many shapes, but are typically in the form of a visible condensation funnel, with the narrow end touching the earth. Often, a cloud of debris encircles the lower portion of the funnel.
Tornadoes can be the most destructive storms on earth. Most have winds of 110 mph or less, are approximately 250 feet across, and travel a mile or more before dissipating. However, some tornadoes can have winds of more than 300 mph be more than a mile across, and stay on the ground for dozens of miles.
They have been observed on every continent except Antarctica; however, a significant percentage of the world's tornadoes occur in the United States. This is mostly due to the unique geography of the country, which allows the conditions which breed strong, long-lived storms to occur many times a year. Other areas which often experience tornadoes are south-central Canada, northwestern Europe, east-central South America, South Africa, and south-central Asia.
