The distinguished ecologist G. Evelyn Hutchinson provided one of the most important explanations for how competing species can coexist. Explain his fundamental niche concept, and how he would account for closely related species coexisting
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Hutchinson suggested that each species has a fundamental niche, a range of environmental conditions (such as its requirement for temperature, food, and water), over which the species might possibly exist. Hutchinson noted that few species actually grow and reproduce in all parts of their theoretical range. Rather, each species usually exists only where they are able to compete effectively against other species: its realized niche. In the 1930s, the biologist G. F. Gause studied interspecific competition, ultimately postulating the competitive exclusion principle: when two species directly compete for essential resources, one species will eventually displace the other. In other words, Hutchinson explained that when the fundamental niche of two species significantly overlaps, these potential competitors are able to coexist because they divide up the fundamental niche, as no two species can occupy the same realized niche.
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Which of the two layers would form the largest folds?
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Suppose we could take the Atlantic Ocean north of the equator and divide it into two compartments along a north-south line (for example, if sea level were much lower and the Mid-Atlantic Ridge was mergent along its length)
What would happen to the North Atlantic Gyre? a) The gyre would grind to a halt because its north and south currents are blocked. b) The Mid-Atlantic Ridge barrier would turn equatorial currents north and northern boundary currents south, resulting in two gyres, one on each side. c) The ridge would cause surface water to sink as it piles up against the barrier and has nowhere else to go. d) The ridge would have almost no effect, and the currents would just go over or around it. e) The ridge would cause deep water upwelling as the currents strike the barrier.
Geologists gain understanding of the formation of magma and igneous rocks by making field observations, geochemical analyses, and laboratory experiments. Give an example of each
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A hiker was bitten on the left lower leg by a rattlesnake. He is conscious and alert, but complains of nausea and generalized weakness. The affected area, which has two distinct puncture wounds, is swollen markedly. The patient's blood pressure is 114/66 mm Hg, pulse rate is 120 beats/min and regular, and respirations are 22 breaths/min and regular. The MOST appropriate treatment for this patient involves:
A) keeping him calm, administering high-flow oxygen, immobilizing the affected extremity and keeping it below heart level, and establishing vascular access. B) applying venous tourniquets proximal and distal to the affected site, elevating the limb no more than 12 inches, applying a splint, and establishing vascular access. C) administering oxygen, providing emotional support, establishing vascular access, administering a 250-mL saline bolus, and splinting the affected extremity. D) placing him in a supine position, elevating the affected extremity and applying ice to reduce the swelling, establishing vascular access, and administering fentanyl for pain.