Govt Exams
This describes the metagenesis (alternation of generations) in Cnidarians. The polyp form is sessile and primarily filter-feeds, while the medusa is motile and actively hunts. Nematocysts and gastrovascular cavity are defining features of Cnidaria. This lifecycle strategy allows the species to exploit different ecological niches and resources.
Sponges lack true tissues (being cellular level organization) and have no nervous, digestive, or circulatory systems, indicating primitive evolutionary status.
Frogs belong to Class Amphibia while snakes belong to Class Reptilia, both are in Phylum Chordata; all other pairs are from different phyla.
The incomplete digestive system with a single opening (gastrovascular cavity) in flatworms is primitive compared to higher animals with complete digestive tracts.
Both hair and scales are epidermal structures but serve different functions: hair insulates in mammals while scales provide waterproofing in reptiles.
Marine fish conserve water by producing concentrated urine and actively excrete excess salts through specialized gill cells, maintaining internal osmotic balance.
Pharyngeal slits function in respiration (aquatic chordates) and are modified into the middle ear structure and eustachian tube in terrestrial vertebrates.
Amphibians uniquely have a biphasic life cycle, spending early life in water as aquatic larvae and later life on land as terrestrial adults, undergoing metamorphosis.
Insects have highly developed tracheal systems with extensive branching allowing efficient terrestrial respiration, unlike crustaceans which use gills.
Echinoderms possess a unique water vascular system derived from the coelom, used for locomotion, feeding, and respiration through tube feet.