Given below are two statements:
Statement I: The Abingdon tortoise in Galapagos Islands became extinct after goats were introduced on the island, apparently due to the greater browsing efficiency of the goats.
Statement II: In some shallow South American lakes, visiting flamingoes and resident fishes compete for their common food, the phytoplankton in the lake.
In the light of the above statements, choose the most appropriate answer from the options given below:
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → Statement I is correct but Statement II is incorrect
Statement I: The Abingdon tortoise in Galapagos Islands became extinct after goats were introduced on the island, apparently due to the greater browsing efficiency of the goats. — True. Goats and the tortoise fed on the same plants, and the goats were better at it. This is one of the book’s pieces of circumstantial evidence for competition in nature.
Statement II: In some shallow South American lakes, visiting flamingoes and resident fishes compete for their common food, the phytoplankton in the lake. — False. The common food of the flamingoes and fishes is the zooplankton, not the phytoplankton. The book uses this case to show that even totally unrelated species can compete for the same resource.
NCERT Extract:
Population Interactions – “… Firstly, totally unrelated species could also compete for the same resource. For instance, in some shallow South American lakes, visiting flamingoes and resident fishes compete for their common food, the zooplankton in the lake.”
Population Interactions – “… Strong and persuasive circumstantial evidence does exist however in some cases. The Abingdon tortoise in Galapagos Islands became extinct within a decade after goats were introduced on the island, apparently due to the greater browsing efficiency of the goats.”