Biology: Frog Morphology and Anatomy

Vocabulary flashcards covering the taxonomy, external morphology, adaptations, sexual dimorphism, and digestive system anatomy of the frog (Rana tigrina).

Taxonomic Classification of Frog (Rana tigrina)

Belongs to Kingdom Animalia, Phylum Chordata, Sub-phylum Craniata / Vertebrata, Super-class Tetrapoda, Class Amphibia, Subclass Lissamphibia, Order Anura, Genus Rana, and Species tigrina.

Indian bullfrog (Rana tigrina / Hoplobatrachus tigerinus)

The most common frog found in India, inhabiting freshwater lakes, streams, and ponds; found worldwide except in Australia and New Zealand.

Poikilothermous

Cold-blooded state in which an animal's body temperature varies and changes according to the surrounding environment.

Aestivation

A state of dormancy and metabolic inactivity known as 'summer sleep' that frogs undergo during extreme heat in summer.

Hibernation

A period of dormancy termed 'winter sleep' during which frogs stop feeding, become metabolically inactive, and respire exclusively through their skin.

Cutaneous respiration

Respiration performed across the skin, serving as the sole method of gas exchange when frogs are metabolically inactive during aestivation and hibernation.

Protective colouration (Camouflage)

Color adaptation featuring spotted olive green skin on the dorsal side and pale yellow skin on the ventral side to protect against enemies.

Dermal plicae

Longitudinal folds of skin located on the dorsal trunk of a frog that increase the surface area available for gaseous exchange.

Nictitating membrane

A transparent fold of the lower eyelid that covers and shields the frog's eye while submerged underwater.

Tympanum

An external auditory organ situated behind the eyes that functions in hearing and receiving sound waves.

Nuptial pad (Copulatory amplexusory pad)

A roughened, deeply colored swelling on the ventral surface of the first digit (base of the thumb) of male forelimbs that develops during the breeding season to grasp the female and release a sticky chemical.

Amplexus

A sexual embrace or false copulation where the male frog clasps the female dorsally during mating season.

Vocal sacs

Paired throat structures present exclusively in male frogs that act as sound resonators during breeding season.

Forelimbs (in frogs)

Anterior appendages divided into three segments—upper arm, forearm, and hand—bearing 4 unwebbed digits.

Hindlimbs (in frogs)

Long, powerful posterior limbs composed of three segments—upper thigh, middle shank, and lower foot—possessing 5 webbed digits used for leaping, jumping, and swimming.

Cloacal aperture

A terminal opening located at the end of the frog's trunk through which fecal matter, urine, and gametes (sperm or ova) are discharged.

Liver (in frogs)

A major digestive gland that secretes bile (stored in the gall bladder), which assists in digestion and the emulsification of fats.

Pancreas (in frogs)

A digestive gland that produces pancreatic juice to facilitate chemical digestion in the alimentary canal.