Round 2: Tossup 2
The value of delta-O-18 measured in foraminifera (“for-uh-min-NIF-er-uh”) and these organisms’ coenosteum (“see-NESS-tee-um”) can extrapolate historical temperatures. Some of these organisms called Scleractinia (“sclair-ac-TIN-ee-uh”) form tree-like growth rings of aragonite. The fact that these organisms flourish in nutrient-poor environments is called Darwin’s paradox. Ecosystems centered on these organisms have “platform” and “fringing” types. Rising temperatures cause symbiotic zooxanthellae (“zoh-uh-zan-THELL-eye”) to be expelled by these cnidarians (“nigh-DARE-ee-ins”), turning them white. These organisms absorb less calcium carbonate into their skeletons when the ocean is acidic. For 10 points, a quarter of the world’s marine life is hosted by what organisms’ reefs? ■END■
ANSWER: corals [accept coral reefs or fringing coral reefs or platform coral reefs; accept coral bleaching; accept stony corals or hard corals; accept soft corals; prompt on Scleractinia or scleractinians until “Scleractinia” is read; prompt on Cnidaria or cnidarians until “cnidarians” is read; prompt on Anthozoa or anthozoans]
<Editors, Biology> | Packet B
= Average correct buzzpoint
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