The latitudinal gradient in species diversity is one of the most striking patterns in the distribution of organisms on the planet. Simply put, the average number of species per unit area increases dramatically the closer the area is to the equator, almost entirely regardless of the type of organism being considered (Pianka, 1994). Researchers investigating the gradient have formulated a wide variety of hypothesis explaining the higher level of species diversity in the tropics. These include but are not limited to: a greater degree of evolution and radiation in tropical species due to the long and relatively stable geological history of the area, seasonal climatic stability and/or predictability, a higher level of productivity, an increased rate of competition and a higher predation intensity (Pianka, 1994). Another theory is that tropical soils somehow influence species diversity and thus cause the latitudinal gradient. This paper will further investigate this final theory by outlining the basic characteristics of tropical soils, summarizing the mechanisms invoked to explain species diversity with these soil characteristics, and evaluating how well this research agrees with what is known about tropical soils. For the sake of narrowing the topic somewhat, attention is limited to the soils of and research occurring in Latin America.
In the past, tropical soils have been over-simplified and misunderstood (Sanchez, 1976), and this situation plagued soil science at least until the late seventies (Van Wambeke and Dudal, 1978). Sanchez (1976) attributes this misunderstanding of tropical soils to the fact that when temperate region-trained soil scientists first went to the...
... middle of paper ...
...s richness in Costa Rican forests: Journal of Biogeography, 7, 147-157.
Jordan, C.F. and Herrera, R., 1981, Tropical rain forests: are nutrients really critical?: American Naturalist, 117, 167-180.
Paoletti, M.G., Taylor, R.A.J., Stinner, B.R., Stinner, D.H., and Benzing, D.H., Diversity of soil fauna in the canopy and forest floor of a Venequelan cloud forest: Journal of Tropical Ecology, 7, 373-383.
Pianka, E.R., 1994. Evolutionary Ecology, Fifth Edition: New York, Harper Collins College Publishers, p. 390-396.
Sanchez, P., 1976, Properties and Management of Soils in the Tropics: New York, John Wiley and Sons, Chapters 2,3,4, and 5.
Van Wambeke, A., and Dudal, R., 1978, Macrovariability of soils of the tropics, p. 13-28 in Stelly, M. (editor-in-chief), Diversity of Soils in the Tropics: Ithaca, Department of Agronomy, Cornell University Press.
Need Writing Help?
Get feedback on grammar, clarity, concision and logic instantly.Check your paper »
- In today’s society everyone seems to have an opinion on everything. It seems the more uninformed one is on a subject the more strongly the feel about it. Occasionally there are those who address issues they are well informed on in a well-organized and civilized manner, weighing both the pros and cons of the side they advocate. Brandon M. Middleton does an exceptional job of this in his article on the Endangered Species Act, where he talks about the effectiveness of the Federal government’s current involvement with endangered species.... [tags: Endangered species, Species]
1423 words (4.1 pages)
- 1. In this graph it is showing discrimination and the generalization gradient. Line B represents the subject receiving food which is also known as the reinforcement when ever it pressed the lever with a continous tone. Line A represents the subject only receiving food it they press the lever when the tone is sounded not during silence periods. That is why you see a sudden increase in response when 1000hz tone is signaled. Line A is displaying considerable discrimination. The subject is able to discriminate when it will receive reinforcement for its lever pressing and when it won’t.... [tags: Reinforcement, Psychology, Operant conditioning]
1152 words (3.3 pages)
- A species of plant or animal classified as endangered is a species that faces the risk extinction. Their possible extinction can be attributed to human activity, climate change, critical habitat loss, disruption in predator/prey ratio, and many other factors. The Endangered Species Act (ESA), established in 1973, is a federal mandate that requires the endangered species to be listed and subsequently protected to avoid future extinction of the species - included is the protection of their critical habitat.... [tags: Endangered species, Species, IUCN Red List]
864 words (2.5 pages)
- Genetic Diversity on Restoration Compilation of all direct and indirect effects on the planet by human activities has become very critical to the restoration of endangered species to their native environment. Efforts around the world are in the works to help preserve many species from disappearing from the face of the earth. In areas where fitness species or population is low, conservation management strategy have been advocated to help avoid extinction. Such case can be seen with the Florida Panthers in which unrelated species from another population was introduced to the population to reestablish the population.... [tags: environmental issues and concerns]
2250 words (6.4 pages)
- Protecting the Endangered The beautiful species of the wild are being endangered more and more each day. Because of the increase of endangered wildlife society now faces several extinctions therefore, to prevent this problem, the government should pass laws or policies that provide greater protection and preservation, provide more information about endangered species, give more publicity to the issue and support charities. “An endangered species is one whose numbers are so small that it is at risk of extinction” (Do Something 2015).... [tags: Endangered species, Extinction, Species, Plant]
1548 words (4.4 pages)
- The term invasive species is described as a species that is introduced into an area in which it is not native. This species has the potential to cause a negative effect to the native species and other biotic factors in those surroundings (Invasive Species, n.d). Any kind of living organism can be a potential invasive species, including the seeds and eggs of an organism (Invasive Species, n.d). These species can be brought into an area any number of ways but are usually a result of human activity (Invasive Species, n.d).... [tags: Invasive species, Introduced species, Ecology]
1787 words (5.1 pages)
- The latter half of the twentieth century was host to the greatest and most widespread advancements in environmental awareness in human history. It was during this time that people began to consider the effects of their polluting cars and their wasteful habits. People began to realize that something must be done to curb humans’ negative impacts on their surroundings and thus the environmental movement was born. One of the most important factors that resulted from this expansion of environmental consciousness occurring over the last several decades has been the protection of endangered species.... [tags: CITES, Endangered Species Act ]
2291 words (6.5 pages)
- Fierce, magnificent, and free. On June 20, 1782 the bald eagle was unofficially declared as the representative of the United States of America. Instead of protecting the national emblem, “on July 4, 1976, the US Fish and Wildlife Service officially listed the bald eagle as a national endangered species” (History of…). The representation of the country’s freedom, strength, and beauty lies heavily on this bird; if it were to become an extinct species, what would that say for the United States. There is a very realistic and near-future solution: cloning.... [tags: extinction, extinct species, technology]
1180 words (3.4 pages)
- Pollution's Effect on the Diversity of Aquatic Invertebrate Species Aim: To investigate whether pollution affects the diversity of aquatic invertebrate species. Equipment: Wash tub, Smaller Margerine Tub Plastic Spoon, Milk Container, Net, Species Analysis Chart. The wash tub has the perfect surface area to count the animals without imprisoning them, the smaller margerine tub allows for the animals to be more carefully analysed so that their species can be more easily determined, the spoons are the perfect size to remove the animals individually, using the milk container is much easier than filling up the wash tub with... [tags: Papers]
1203 words (3.4 pages)
- Supporting Diversity “Without awareness and knowledge of gender, race, culture, and ethnicity, therapists and other helping professionals could unwittingly engage in cultural oppression (A. Dunklin, Ph.D., personal communication, October, 2009). Dr. Dunklin is accurate in his statement. After surviving the destruction of the Third Reich, the civil rights’ movement of the 1960s and the women’s movement of the 1970s, it is hard to understand why the need for diversity still has to be discussed except that as a society, we are infants when dealing with diversity issues.... [tags: Diversity]
2637 words (7.5 pages)
- Impacts of Global Climate Change on Temperature and Precipitation Patterns in the Midwest and the Consequences for Soils
- The Study of the Affects of Long Term Agruculture on the Soils of Europe
- Nitrogen and Irrigation on Coastal Plains Soils
- Effects of Corn Monoculture on Soils: Models for Change in American Agriculture
- An Overview of Indonesia's Soil Sickness
- Trento and Vicenza