11 results found, view free essays on page:
Ice Age Extinctions Of The Megafauna
1,675 wordsICE AGE EXTINCTIONS OF THE MEGAFAUNA During the last Ice Age before humans arrived, the North American continent belonged to various forms of enormous, fantastic creatures. By the end of the Ice Age, most of these large animals had become extinct. Numerous attempts have been made to explain the disappearance of these animals, but there has yet to be a consensus. Among the theories that have been debated, two are predominant. They are the climatic change theory, and the overkill theory. The clima...
Free research essays on topics related to: 000 years ago, ice sheets, 10 000 years, million years ago, ice age
Million Years Ago 65 Million Years
2,114 wordsThe "Nemesis Theory" was an outgrowth of the discovery of Alvarez et al. , that the impact of a large (10 km diameter) comet or asteroid was responsible for the great mass extinction that took place 65 million years ago. Studies of the fossil record by Dave Raup and Jack Sepkoski shows that this was not an isolated event, but one of several mass extinctions that appear to occur on a regular 26 million year cycle. Their original paper analyzed marine fossil families, and was published in the Proc...
Free research essays on topics related to: billion years, solar system, mass extinctions, million years ago, 65 million years
Rivers Have Begun Flow In Their Present Courses Species
2,554 words... he destruction of the animals of which the remains are now so curiously preserved, has been something of sudden and instantaneous operation. Of this, however, we do not think that the proof is quite satisfactory; and though the thing may be true in some instances, we believe that in far the greater number it cannot be admitted. The rhinoceros, of which the skeleton with some parts of the muscles and the hide, was found near the banks of the Lena, must no doubt have been frozen soon after its...
Free research essays on topics related to: strata, fossil, fresh water, bones, remains
Analysis Of Charles Darwin Origin The Species
1,048 wordsCharles Darwin in his book, On the Origin of Species, presents us with a theory of natural selection. This theory is his attempt at an explanation on how the world and its species came to be the way that we know them now. Darwin writes on how through a process of millions of years, through the effects of man and the effects of nature, species have had a trial and error experiment ongoing. It is through these trials that the natural world has developed beneficial anomalies that at times seem too ...
Free research essays on topics related to: optic nerve, theory of natural selection, millions of years, darwin theory, origin of species
Gene Pool Northern Hemisphere
1,207 wordsIntroduction It is unlikely that any family of fish has received as much attention as the Salmoninae. Many have a particularly heart-felt interest in the Salmoninae (trout, salmon, and char) because they love to fish. But man often destroys that which he loves, and the Salmoninae are no exception to this phenomenon. Exploitation of these fish has led to the extinction of certain species in some areas, but the attempt to preserve our valued fisheries has resulted in extensive research on the Salm...
Free research essays on topics related to: northern hemisphere, fresh water, north america, gene pool, million years
Southern Hemisphere Columbia River
1,251 words... and does not create cold rivers and lakes. Thus we don't find the parallel evolution of fish into similar forms in the southern hemisphere. The Salmonids can not in any manner cross the warm tropical region and therefore did not colonize what suitable regions there are for them in the southern hemisphere. But with man's help they can, and rainbow trout are now found on every continent except Antarctica. Let us assume that an original Salmonid ancestor originated in a cold fresh water lake or...
Free research essays on topics related to: columbia river, north america, ice sheet, southern hemisphere, fresh water
3 7 M 12 Ft 7 M 12 Ft Long Boa
296 wordsBoa is the common name for about 6 genera and 50 species of SNAKES that constitute the family Bondage. Closely related to PYTHONS, the family includes the largest of all snakes, the water-dwelling ANACONDA of South America. Among other boas are the smaller sand boas, Eye, and the wood snakes, Tropidolphus and related genera. The typical boa genera are ground or tree dwellers of tropical American are the woodsnakesand the island of Madagascar, whereas the sand boas are semidesert burrowing snakes...
Free research essays on topics related to: ft long, boas, snakes, genera, sand
Long Slender Beaks Found In Tropical Dolphins
509 wordsThe mammalian dolphins are small, streamlined whales, usually with a well-defined, bearlike snout. They are often called porpoises, but that name is usually reserved for similar, but beatles, whales of the family Phocoenidae (see porpoise). Dolphins are popularly noted for grace, intelligence, playfulness, and friendliness to man. The most widely recognized species are the common and bottle-nosed dolphins (Delphinus delphi's and Tursiops truncated; see photograph); both are of the family Delphin...
Free research essays on topics related to: whales, dolphins, genera, dolphin, slender
Cell Membrane Host Cell
999 wordsLASSA FEVER; AN OLD WORLD ARENAVIRUS ABSTRACT A brief summary of lassa fever, its history, pathology and effects on the indigenous populations. Also, lassa fever in the context of newly emerging diseases. LASSA FEVER On January 12, 1969, a missionary nun, working in the small town of Lassa, Nigeria, began complaining of a backache. Thinking she had merely pulled a muscle, she ignored the pain and went on about her business. After a week, however, the nurse had a throat so sore and so filled with...
Free research essays on topics related to: viruses, endemic, fever, cell membrane, host cell
Cell Membrane Host Cell
819 wordsLassa Fever: An Old World Arenavirus ABSTRACT A brief summary of lassa fever, its history, pathology and effects on the indigenous populations. Also, lassa fever in the context of newly emerging diseases. LASSA FEVER On January 12, 1969, a missionary nun, working in the small town of Lassa, Nigeria, began complaining of a backache. Thinking she had merely pulled a muscle, she ignored the pain and went on about her business. After a week, however, the nurse had a throat so sore and so filled with...
Free research essays on topics related to: host cell, viruses, fever, cell membrane, rna
Lower Low Water 20 Degrees C Californianus
1,189 wordsMytilus Californianus, Mytilus Californianus Introduction Mytilus Californianus, also known as the California mussel, is one of the most common creatures on California's rocky shores and in tide pools. They are generally grayish black in color and have very hard shells that only the strongest (or smartest) of predators can open. These mussels attach themselves to rocks very tightly. From time to time they sneak their foot out and touch the rocks, secreting a special thread of cement. After doing...
Free research essays on topics related to: mussel, mussels, coast, degrees c, rocks
11 results found, view free essays on page: