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Listen to an Academic Talk Test #047
Listen to an Academic Talk
1. What is the lecture mainly about?
A) The nesting habits of warblers
B) A specific type of reproductive behavior
C) The physical characteristics of cuckoos
D) How birds learn to recognize their young
2. According to the professor, what does a cuckoo chick often do?
A) It mimics the calls of the host's chicks.
B) It shares food with the other birds in the nest.
C) It removes the host''s eggs from the nest.
D) It helps the host parents build a stronger nest.
3. What does the professor imply about a host bird that rejects a cuckoo egg?
A) It has likely mistaken the egg for food.
B) It may be part of an evolutionary adaptation.
C) It is probably a less attentive parent.
D) It will abandon its nest and build a new one.
4. Why does the professor mention an "evolutionary arms race"?
A) To explain the competition between parasites and hosts
B) To describe a conflict between different cuckoo species
C) To show why brood parasitism is becoming rare
D) To give an example of cooperation in nature
Professor: Let's talk about a fascinating and rather ruthless survival strategy in the animal kingdom known as brood parasitism. This is when an animal, the parasite, tricks another animal, the host, into raising its young. The most famous example is the common cuckoo.
A female cuckoo will lay her egg in the nest of a smaller bird, like a warbler. The cuckoo egg is often a close visual mimic of the host's eggs. After the cuckoo chick hatches—often before the host's own chicks—it instinctively pushes the other eggs or chicks out of the nest.
This ensures it receives all the food the host parents bring. This interaction leads to what biologists call an "evolutionary arms race." The host species is under pressure to evolve the ability to recognize and reject parasite eggs, while the parasite is under pressure to evolve even better mimicry to fool the host.
A female cuckoo will lay her egg in the nest of a smaller bird, like a warbler. The cuckoo egg is often a close visual mimic of the host's eggs. After the cuckoo chick hatches—often before the host's own chicks—it instinctively pushes the other eggs or chicks out of the nest.
This ensures it receives all the food the host parents bring. This interaction leads to what biologists call an "evolutionary arms race." The host species is under pressure to evolve the ability to recognize and reject parasite eggs, while the parasite is under pressure to evolve even better mimicry to fool the host.
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