California Thrasher Essay

1373 Words3 Pages

Midterm Exam
Question 3:
Niche theory is a very important concept in Ecology. However, the exact meaning of the concept has changed throughout the years. Joseph Grinnell introduced the idea of niche theory in his paper “The Niche-Relationships of the California Thrasher”. His idea was that a species is restricted to its niche because of the habitat it lives in and its behavioral patterns. In Grinnell’s paper, the California Thrasher stays within the chaparral habitat of California. He continues to say that the California Thrasher is restricted by humidity and temperature, but that is probably due to the fact that this is the best environment for the chaparral bushes. The California Thrasher is described as a “shy bird” so it uses the cover …show more content…

In 1927, Charles Elton took niche theory a step further and included food. He defined the niche of an animal as its place in the biotic environment and its relations to food and enemies (Elton, 1927). Grinnell also wondered if food was a limiting factor to the California Thrasher’s niche, but since the bird is omnivorous, it could find food in other habitats such as a forest floor or a meadow. There had to be other factors that restricted the bird to the chaparral bushes (Grinnel, 1917). Elton believes that the niche of an animal can be defined by its size and its food habits. It is important to study niches because it enables ecologists to see how different animal communities may resemble each other in the essentials of organization (Elton, 1927). For example, in a forest there could be a niche of owls that feeds on small animals such as rats. This same carnivore niche is filled with kestrels in the open grasslands. This carnivore niche is then dependent on the small animals in the herbivore niche (Elton, 1927). Hutchinson also discusses niche theory in his “Concluding Remarks” paper. His theory seems to combine some of the ideas …show more content…

In other words, a fundamental niche is where an organism can use all the resources (food, shelter, light, etc.) it needs to survive and reproduce without the interference from other species. This takes ideas from Elton because it states that food is an important part of a niche. However, Hutchinson also introduced the realized niche, the actual niche that an animal is restricted to because of outside forces such as predators and competition (Hutchinson, 1957). This is similar to Grinnell’s idea because the California Thrasher could live outside the chaparral zone because it has a diverse diet, but its realized niche is the chaparral zone because it is restricted there because of predators. Because of this, niches aren’t easy to define in nature because scientists can figure out what the ideal niche would be for an organism but multiple outside forces can make it difficult to determine its realized niche. In recent years, niche theory has not been restricted to ecology and in fact can be applied to cancer research. Studies have found that stem cells differentiate into cancer stem cells causing Cancer in

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