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Listen to an Academic Talk Test #076
Listen to an Academic Talk
1. What is the lecture mainly about?
A) The diet of sea otters and wolves
B) A type of species with a major ecological role
C) The history of Yellowstone National Park
D) Methods for studying kelp forests
2. According to the professor, what is a direct result of a large sea urchin population?
A) The recovery of riverbank vegetation
B) An increase in the sea otter population
C) The destruction of kelp forest habitats
D) A change in deer grazing behavior
3. What does the professor imply about conservation efforts?
A) They are most effective when focused on a single issue.
B) They should prioritize the protection of keystone species.
C) They often fail to consider the role of predators.
D) They have been more successful in parks than in oceans.
4. Why does the professor mention the reintroduction of wolves in 1995?
A) To give another example of a keystone species's impact
B) To discuss a specific date in conservation history
C) To contrast it with the sea otter example
D) To introduce the topic of national parks
Professor: Today we'll discuss keystone species. A keystone species is an organism that has a disproportionately large effect on its ecosystem relative to its abundance. Their removal can dramatically alter the entire community.
A classic example is the sea otter in the kelp forests of the Pacific coast. Sea otters eat sea urchins, which in turn feed on kelp. Without otters, the sea urchin population explodes and consumes all the kelp, destroying the forest habitat that many other species depend on.
A similar effect was seen with wolves in Yellowstone National Park. After their reintroduction in 1995, their presence changed the grazing behavior of deer, allowing vegetation along rivers to recover.
The concept of keystone species is therefore critical for conservation biology, as it highlights that protecting just one species can be key to preserving an entire ecosystem.
A classic example is the sea otter in the kelp forests of the Pacific coast. Sea otters eat sea urchins, which in turn feed on kelp. Without otters, the sea urchin population explodes and consumes all the kelp, destroying the forest habitat that many other species depend on.
A similar effect was seen with wolves in Yellowstone National Park. After their reintroduction in 1995, their presence changed the grazing behavior of deer, allowing vegetation along rivers to recover.
The concept of keystone species is therefore critical for conservation biology, as it highlights that protecting just one species can be key to preserving an entire ecosystem.
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