Diversity of Living World (Medical Entrance)

Hirudin is a potent anticoagulant protein produced in the salivary glands of leeches (Hirudo medicinalis). It prevents blood clotting by inhibiting thrombin, allowing leeches to feed on blood without it coagulating. Hirudin has medical applications in treating blood clots.

The receptor pigment for light in the eyes of all land vertebrates is rhodopsin.

Spongilla is a well-known genus of freshwater sponges. The other options are marine sponges.

Pycnopodia helianthoides, commonly known as the sunflower sea star, is widely recognized as one of the largest starfish species in the world.

Chloragogen cells in earthworms are specialized cells that perform functions analogous to the vertebrate liver, primarily involving excretion and metabolism.

Hemocyanin is a copper-containing respiratory pigment found in the blood of many crustaceans, mollusks, and other arthropods.

The juvenile hormone in insects is secreted from corpora allata.

Presence of cloaca is a reptilian feature of a prototherian mammal.

Phrynosoma is the genus commonly known as horned toads or horned lizards due to their flattened, toad-like bodies and prominent head spines. The other options refer to various frog genera.

The life cycle of Fasciola hepatica follows the sequence: Miracidium, Sporocyst (not listed), Redia, Cercaria, and finally Metacercaria. Therefore, the sequence i, iii, ii, iv is correct.

Sphenodon, commonly known as the Tuatara, is a unique reptile found in New Zealand. It is the only surviving member of the order Rhynchocephalia and is often called a living fossil.

 The foramen present in the heart of a crocodile is foramen of Panizza.

 Limbs and girdles are generally not found in snakes, but vestiges of the pelvic girdle and hind limbs persist in python.

Taenia (tapeworm) has a hexacanth larva, Ascaris has a rhabditoid larva, and Planaria (a flatworm) typically reproduces through regeneration or direct development without a distinct free-living larval stage in the same sense.

The poison glands of snakes are modified salivary glands (specifically the parotid glands). This homology is a well-documented evolutionary adaptation in venomous snakes.

 Presence of notochord, dorsal tubular nerve cord and pharyngeal slits are the three important characters of phylum Chordata. In Branchiostoma, all the three characters are present in the adult form.

Mammals are characterized by a double occipital condyle, the presence of a left aortic arch (the right is lost), and the order Cetacea includes aquatic mammals like whales and dolphins.

Dracunculus medinensis is the Guinea worm, not a filarial worm (which are typically Wuchereria species). The other pairs are correctly matched.

The epidermis of mammalian skin is organized from the surface inward as: stratum corneum, stratum lucidum, stratum granulosum, stratum spinosum, and stratum germinativum (basale).

  Echidna, armadillos and platypus are considered to be toothless mammals.

Claspers are modified pelvic fins in male elasmobranchs (sharks, rays) used for internal fertilization. The other options are incorrect pairings of organs and animals.

The Indian mugger crocodile is Crocodilus palustris, and the Indian gharial is Gavialis gangeticus. These are the correct scientific names.

The Portuguese man-of-war (Physalia physalis) is a siphonophore, which is a colony of specialized zooids belonging to the phylum Coelenterata (Cnidaria).

Monotremata is the order of egg-laying mammals (e.g., platypus, echidna), which are the exception to the general mammalian characteristic of vivipary.

Prosimians are a group of primates that includes lemurs, lorises, and tarsiers. All three are correctly identified as examples.

Neoteny (or paedomorphosis) is the retention of larval features in the adult. It is well-documented in Necturus (mudpuppy), and often observed in other salamanders like Ambystoma (axolotl).

Aschelminthes (nematodes) are characterized by having a pseudocoelom, which is a body cavity not completely lined by mesoderm.

Aplysia, commonly known as the sea hare, is a genus of medium-sized to very large sea slugs, which are marine gastropod mollusks.

The Ammocoete larva is the larval stage of lampreys, which are jawless fish belonging to the order Petromyzontiformes.

Crinoidea is a class of echinoderms that includes sea lilies and feather stars, characterized by a stalked or unstalked body with feathery arms.

Mastigophora - Locomotion by flagella
Sarcodina - Locomotion by pseudopodia
Sporozoa - No locomotory organs