Question

Which of the following are true or false

1) Birds evolved wings before insects did.

2) Once ancient molluscs (Phylum Mollusca) had achieved a domed shell, they differentiated into different Classes when selection favored modification of the shell by either dividing the shell horizontally down the length of the body (Class Polyplacophora = “chitons”), longitudinally (into two equal halves) down the length of the body (Class Bivalvia = “clams”), or by extending the length (or “height”) of the domed shell with or without an opening at the tip (Class Scaphopoda = “tooth shells”, Class Gastropoda = “snails” and relatives, Class Cephalopoda = “cephalopods”).

3) The Atinopterygii (the “ray-finned fishes) belong to the Phylum Chordata, Subphylum Craniata/Vertebrata, Class Osteichthyes (= the “boney fishes”). The Actinopterygians are the most diverse group of Craniates/Vertebrates living today in terms of number of species.

4) Scleractinian corals (those comprising our modern coral reefs) acquired intracellular Dinoflagellate symbionts in the Mesozoic. One of the primary benefits that the coral receives from this symbiotic relationship is that the symbiont facilitates faster calcification (= faster growth) in the coral, allowing the coral to better compete for space.

Answer 1

1. Birds evolved wings before insects did- false because insects did it first as outgrowths from the insect body wall

2. Ancient molluscs had achieved into domed shell , they differentiate into different classes by modification of the shell mentioned in the question- true

3. The actinopterygians are the most diverse group of vertibrates/ cranates living today as mentioned in question - true because they belong to bony fishes are very diverse animals and categorised in many ways.

4. Sclecractinian corals acquired intracellular dinoflagellate symbionts in the mesozoic as mentioned I question- false because unicellular dinoflagellate symbionts in the paleozoic.