A group of researchers procured some fish like animals and upon investigation the following characters were observed: A. Endoskeleton was made of cartilage. B. Ectoparasitic; as they were found attached on fish skin with their circular sucking mouth. C. Paired fins and scales were absent, but 7 pairs of gill slits were present. Which of the following species of animals did they consider to fit best with these characters?

Related Formula

Aptenodytes (Penguin) arrow Flightless bird with paddle-like flippers for swimming$\text{Aptenodytes (Penguin)} \rightarrow \text{Flightless bird with paddle-like flippers for swimming}$

Core Logic

• Aptenodytes (Penguin) is a flightless bird whose forelimbs are modified into paddle-like flippers adapted for swimming.
• Struthio (Ostrich) is a flightless bird, but its forelimbs are reduced and not adapted for swimming.
• Neophron (Vulture) and Psittacula (Parrot) are flying birds.

Step 1: Conclusion

The correct flightless bird with paddle-like forelimbs for swimming is Aptenodytes.

Pattern Recognition

Sees: "flightless bird paddle-like structures swimming". Shortcut: Aptenodytes (Penguin).

Chapter Mix

Class 11 Biology: Animal Kingdom

Related Formula

Class Osteichthyes (Bony Fishes): Flying fish (Exocoetus), Angel fish (Pterophyllum), Fighting fish (Betta)$\text{Class Osteichthyes (Bony Fishes): } \text{Flying fish (Exocoetus), Angel fish (Pterophyllum), Fighting fish (Betta)}$

Core Logic

Evaluating the options:

• Option (1): Devil fish (Octopus) and Cuttlefish (Sepia) are Molluscs; Hagfish (Myxine) is a Cyclostome.
• Option (2): Starfish (Asterias) is an Echinoderm.
• Option (3): Flying fish (Exocoetus), Angel fish (Pterophyllum), and Fighting fish (Betta) are all bony fishes belonging to Class Osteichthyes.
• Option (4): Saw fish (Pristis) and Dog fish (Scoliodon) belong to Class Chondrichthyes (cartilaginous fishes).

Step 1: Conclusion

Option (3) correctly lists members belonging exclusively to Class Osteichthyes.

Pattern Recognition

Sees: "Class Osteichthyes set". Shortcut: Flying fish (Exocoetus), Angel fish (Pterophyllum), Fighting fish (Betta).

Chapter Mix

Class 11 Biology: Animal Kingdom

Related Formula

Adult Echinoderms = Radial symmetry, Reptilia = Poikilothermous (Cold-blooded)$\text{Adult Echinoderms} = \text{Radial symmetry}, \quad \text{Reptilia} = \text{Poikilothermous (Cold-blooded)}$

Core Logic

Evaluation of statements:

• A (Correct): Platyhelminthes have a single opening to the exterior serving as both mouth and anus (incomplete digestive system).
• B (Incorrect): Adult echinoderms exhibit RADIAL symmetry; bilateral symmetry is present in their larval forms.
• C (Correct): Aschelminthes are pseudocoelomates.
• D (Correct): Notochord persists throughout life in Chondrichthyes.
• E (Incorrect): Reptiles are poikilotherms (cold-blooded) and cannot maintain a constant body temperature.

Step 1: Conclusion

Statements B and E are incorrect.

Pattern Recognition

Sees: "adult echinoderms bilateral symmetry" (False, radial) and "reptiles maintain constant body temp" (False, cold-blooded). Shortcut: Incorrect statements are B and E.

Chapter Mix

Class 11 Biology: Animal Kingdom