Ecological Niches · Paper 2 — Free Biology HL Practice Questions

In a tropical rainforest in Borneo, three species of fig wasp (Ceratosolen spp.) are the only pollinators of three closely related fig tree species (Ficus spp.). Each wasp species enters the figs of only one Ficus species, where it lays eggs and pollinates the flowers. The wasps are active at different times of day: Species A at dawn ($05\!:\!00$–$07\!:\!00$), Species B at midday ($11\!:\!00$–$13\!:\!00$), and Species C at dusk ($17\!:\!00$–$19\!:\!00$). Researchers recorded the mean number of wasp individuals captured per hour near each Ficus species. Near Ficus 1 — 45 — 2 — 1 — 48 Near Ficus 2 — 3 — 52 — 4 — 59 Near Ficus 3 — 2 — 1 — 48 — 51

Both species of parrotfish feed on algae growing on dead coral on the Great Barrier Reef, but differ in feeding behaviour. Chlorurus microrhinos (steephead parrotfish) uses large beak-like teeth to scrape deep into the coral substrate, ingesting calcium carbonate. Scarus frenatus (bridled parrotfish) browses only surface algae. Researchers measured algae removal and coral substrate erosion in areas where each species was the dominant grazer. Species — Algae removed / $\text{g m}^{-2}\text{day}^{-1}$ — Substrate eroded / $\text{g m}^{-2}\text{day}^{-1}$ C. microrhinos — $120$ — $85$ S. frenatus — $95$ — $12$