Still, it is not unimaginable, within a lake as large as Victoria that they might also divide into separate populations along very subtle lines of variation -- like mating behaviors or feeding preferences.
This sort of interpretation of the situation in Lake Victoria, however, rests upon the notion that the species of cichlid found there evolved from a single ancestral species. Yet, even Meyer acknowledges that this might not be the case: "Within the past decade, however, morphology has increasingly emphasized the view that the flock may be polyphyletic." Put differently, it is possible that the species of cichlid that have evolved in Lake Victoria came from a group of distinct, but closely related, fish that colonized the region several thousand years ago. If this is the case, then the scientific importance of the Victorian cichlids would be somewhat diminished, because a less explosive series of adaptive radiations could explain their modern occurrence.
Even so, it is difficult to discount the value of the scientific consequences that a better understanding of the mechanisms that brought about the expansion of the haplochromines -- the informal designation of the cichlid groups -- in Lake Victoria would represent. If indeed they did descend from a single species, then it would bring together two major theories within the realm of evolutionary theory: adaptive radiation and punctuated equilibrium. The situation in Lake Victoria could, in fact, validate the underlying notions that Darwin expressed...
Furthermore, it would bring into question some of the ideas surrounding population isolation with reference to speciation.
Goldschmidt, Tijs. 1998. Land-Use Changes and NIS in Lake Victoria. Bright and Lodge, 1998.
Kolar, Cynthia S. And David M. Lodge. 2000. Invasive Species in a Changing World. Washington D.C.: Island Press.
Meyer, Axel et al. 1990. Monophyletic Origin of Lake Victoria Cichlid Fishes Suggested by Mitochondrial DNA Sequences. Nature, 347.
Office of Protected Resources. 2005. Endangered Species Act of 1973. NOAA Fisheries. Available:
Wilson, Edward O. 1992. The Diversity of Life. New York W.W. Norton and Company.
Office of Protected Resources. 2005. Endangered Species Act of 1973. NOAA Fisheries. Available: http://www.nmfs.noaa.gov/pr/laws/esa.htm.
Kolar, Cynthia S. And David M. Lodge. 2000. Invasive Species in a Changing World. Washington D.C.: Island Press. Page 15.
Wilson, Edward O. 1992. The Diversity of Life. New York W.W. Norton and Company. Page 108.
Goldschmidt, Tijs. 1998. Land-Use Changes and NIS in Lake Victoria. Bright and Lodge, 1998. Page 8.
Meyer, Axel et al. 1990. Monophyletic…
Meech Lake Accords In order to properly examine the Meech Lake Accords and their significance, we must look first at why the Accords were necessary and what led up to them. Until 1982, Canada had been governed by the British North America Act, passed by the British Parliament in 1867. This act provided for the unification of the Canadian provinces into the Dominion of Canada, and set out the powers
But after local wastewater plants were "...upgraded and farms' management practices were improved, the amount of phosphorus declined and the copper sulfate was no long considered necessary" (Royte, 2007). The Times' story reports that to prevent the dumping of partially treated sewage water into the waterways, septic tanks need to be upgraded and "cleaning the water in sewage treatments plants even more thoroughly before it is discharged into the
International Regulation of Tourism in Antarctica Since the mid-1980s, Antarctica has been an increasingly popular tourist destination, despite the relative danger of visiting the largest, least explored -- and arguably least understood -- continent on earth. Beginning with the 1959 treaty establishing Antarctica as an international zone free of claims of sovereignty by nation's that had been instrumental in establishing research stations there, there has been almost constant negotiation about how
The source of the current crisis can be traced to 1998 when an initial agreement was reached on a plan of action and policy guidelines to establish the Nile Basin Initiative at the 2nd Nile Technical Advisory Committee meeting held in Arusha. A few months later, the Nile Basin Initiative (NBI) was officially launched at an extraordinary meeting of the Nile Basin Council of Ministers, in Dar es Salaam,
The quality life would include provision of good education, health care, adequate employment opportunities, safe drinking water and clean air, reduction of crime and many more (World Bank 2004, p.1). This report also poses that a country will only be deemed developed when life expectancy increases, provide average income and ensure adult literacy. In brief human development involves all features of individuals' well-being, this range from health condition to
Origins, History of the IMF The International Monetary Fund was first conceived between July 1-22, 1944, at the United Nations Monetary and Financial Conference in Bretton Woods, New Hampshire. The conference was attended by representatives of 45 nations, which were called together in order to plan and lay the groundwork for a cooperative economic framework to solve global financial crises before they occur. One key reason for the conference was to