Read the passage and answer the following questions:
Organisms evolve in their respective habitats to maximise their reproductive fitness, also known as Darwinian fitness, which is often measured by a high "r" value. They adapt to the specific selection pressures present in their environment by developing the most efficient reproductive strategies. This includes variations in breeding frequency and the number and size of offspring produced. Some organisms, such as Pacific salmon fish and bamboo, exhibit a strategy known as semelparity, where they breed only once in their lifetime. In contrast, most birds and mammals follow an iteroparous strategy, breeding multiple times throughout their lives. Additionally, some species, like oysters and pelagic fishes, produce a large number of small-sized offspring, while others, such as birds and mammals, produce a small number of large-sized offspring. The desirable reproductive strategy for maximising fitness depends on the specific conditions and selection pressures within the habitat. Ecologists emphasise that the evolution of life history traits is influenced by the constraints imposed by the abiotic and biotic components of the environment. Factors such as resource availability, competition, predation, and other ecological interactions shape the evolution of these traits. Thus, populations evolve to maximise reproductive fitness in their habitats, and the specific reproductive strategies and traits they adopt depend on the selection pressures and constraints present in their environment. Ecologists investigate these relationships to uncover the mechanisms behind the evolution of life history traits and their ecological significance.
Which group of organisms typically produces a large number of small-sized offspring?
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → Oysters and pelagic fishes
The passage states that “some species, like oysters and pelagic fishes, produce a large number of small-sized offspring”.
Organisms differ in how they spend their resources on offspring. Some make many small offspring, with little care for each; others make a few large offspring.
Option (1) Birds and mammals — Incorrect. Birds and mammals produce a small number of large-sized offspring.
Option (2) Oysters and pelagic fishes — Correct. Oysters and pelagic fishes (fishes of the open sea) release a very large number of small offspring.
Option (3) Pacific salmon fish and bamboo — Incorrect. Pacific salmon fish and bamboo are examples of organisms that breed only once in their lifetime. The passage does not use them for offspring size.