An Introduction to Evolution

An Introduction to Evolution

What is Evolution? Evolution is the process by which all living things

have developed from primitive organisms through changes occurring over billions

of years, a process that includes all animals and plants. Exactly how evolution

occurs is still a matter of debate, but there are many different theories and

that it occurs is a scientific fact. Biologists agree that all living things

come through a long history of changes shaped by physical and chemical processes

that are still taking place. It is possible that all organisms can be traced

back to the origin of Life from one celled organims.

The most direct proof of evolution is the science of Paleontology,

or the study of life in the past through fossil remains or impressions, usually

in rock. Changes occur in living organisms that serve to increase their

adaptability, for survival and reproduction, in changing environments. Evolution

apparently has no built-in direction purpose. A given kind of organism may

evolve only when it occurs in a variety of forms differing in hereditary traits,

that are passed from parent to offspring. By chance, some varieties prove to be

ill adapted to their current environment and thus disappear, whereas others

prove to be adaptive, and their numbers increase. The elimination of the unfit,

or the "survival of the fittest," is known as Natural Selection because it is

nature that discards or favors a particular being. Evolution takes place only

when natural selection operates on apopulation of organisms containing diverse

inheritable forms.

HISTORY

Pierre Louis Moreau de Maupertuis (1698-1759) was the first to

propose a general theory of evolution. He said that hereditary material,

consisting of particles, was transmitted from parents to offspring. His opinion

of the part played by natural selection had little influence on other

naturalists.

Until the mid-19th century, naturalists believed that each species

was created separately, either through a supreme being or through spontaneous

generation the concept that organisms arose fully developed from soil or water.

The work of the Swedish naturalist Carolus Linnaeus in advancing the classifying

of biological organisms focused attention on the close similarity between

certain species. Speculation began as to the existence of a sort of blood

relationship between...

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...y different. For example, the wing of a bird and the wing of a

butterfly are analogous; both are used for flight, but they are entirely

different structurally. Analogous structures do not indicate evolutionary

relationships.

Closely related fossils preserved in continuous successions of rock

strata have allowed evolutionists to trace in detail the evolution of many

species as it has occurred over several million years. The ancestry of the horse

can be traced through thousands of fossil remains to a small terrier-sized

animal with four toes on the front feet and three toes on the hind feet. This

ancestor lived in the Eocene Epoch, about 54 million years ago. From fossils in

the higher layers of stratified rock, the horse is found to have gradually

acquired its modern form by eventually evolving to a one-toed horse almost like

modern horses and finally to the modern horse, which dates back about 1 million

years.

CONCLUSION TO EVOLUTION

Although we are not totally certain that evolution is how we got the way

we are now, it is a strong belief among many people today, and scientist are

finding more and more evidence to back up the evolutionary theory.