1. Native species of North America are often defined as those species that were
ID: 284943 • Letter: 1
Question
1. Native species of North America are often defined as those species that were present in North America before Europeans arrived in the early 1600s. When Europeans arrived, they found extensive forests dominated by the American chestnut tree. These chestnut trees were extensively cultivated and planted by the North American natives for food and other wood products. In the early 1900s the chestnut blight (a fungus) virtually exterminated all of the American chestnut trees from North America.
(a) Is the American chestnut considered a native species despite its intensive cultivation? Explain why.
(b) Is the chestnut blight considered a native or invasive species? Explain why.
(c) Discuss why invasive species tend to proliferate at very high rates.
(d) Many people are trying to grow hybrid chestnut trees that will be immune to the chestnut blight so that forests can be restored to those found by the Europeans in the 1600s. Do you agree or disagree that this should be done? Justify your answer
Explanation / Answer
a. Since native species of North America are defined as those which were present in the North America before the arrival of the Europeans in the early 1600s. Since the European saw that there were extensive forests of American chestnut tree and these trees were extensively cultivated by the natives of North American for food and other products. So based on the defination of native species of North American we can say that it the American chestnut were considered native speces despite their intensive cultivation..
b. The chestnut blight cannot be considered as native species because they arrived in the early 1900s after the European arrival. For a species to be called native species it should be present in North America before the arrival of Europeans i.e early 1600s. An invasive species can be any plant, animal or fungal species that is not native to a particular location and is harmful to the environment. Since chestnut blight was a fungus which eliminated all the American chestnut trees therefore it was considered an invasive species.
c. Invasive species are not native to a particular location and are introduced into a new environment. An introduced species may become invasive if they are able to outcompete the native species for resources like nutrients, space, water, light etc. If these introduced species developed under greater competition or predation and the new environment have lesser predators or competitors then these invasive species are able to proliferate easily. So the new environment becomes more favourable to them as compared to the native species. These invasive species remain with the native species for an extended period of time and gradually their competitive superiority becomes apparent with their population becomes larger and denser eliminating the native species.
d. Efforts are being made by scientists to develop hybrid chestnut trees to restore the American chestnut forest. One of the method is the backcross of the resistant species either Chinese or Japanese species with the native American species. The strategy is to develop blight resistant species while preserving the more wild type traits of American chestnut trees as the dominant phenotypes so that the newly hybrid varieties should reach the same height as the native American chestnut trees. For a hybrid to be successful an area with good drainage and proper sunlight is necessary and these requirements are hard to met so not all restoration areas are successful with hybrid survival.
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