Aquatic and Marine Biology

Potamogeton is a genus of aquatic, mostly freshwater, plants of the family Potamogetonaceae.

Mammals have mammary glands that help them to feed their babies.

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Fish covers some distance after swimming and man covers some distance after walking. 

Ammonia, urea and uric acid are the excretory products in different animals. Ammonia is an excretory product in gaseous form in fishes, uric acid (white in colour) is in birds and urea is an excretory product in human beings.

Heart of a fish is special because it only has venous blood.

Byssus means both a silky filament by which certain molluscs attach themselves to hard surfaces, and a rare fabric, also called sea silk and its fibre source. It generally refers to a filament created by certain kinds of marine and freshwater bivalve molluscs, which use it to attach themselves to rocks, substrates or sea beds.

Pisciculture derives from the Latin word 'pisces' meaning fish, and refers to the controlled breeding, rearing, and harvesting of fish in controlled environments like ponds, tanks, or cages. It is a subset of aquaculture and is distinct from animal husbandry (sheep/cattle rearing) or agriculture (vegetable cultivation).

Fish use gills to extract oxygen from water during respiration. Lungs are used by mammals and other terrestrial animals for breathing air, not by fish. Ears are for hearing, not respiration.

Vitelline membrane is found in the ovum of birds.

Pearls are formed inside oysters (marine bivalve mollusks) as a defense mechanism against irritants like parasites or debris. When an irritant enters the shell, the oyster secretes nacre (mother-of-pearl) around it, gradually forming a pearl.

Homodont means all teeth are similar in shape. Frogs have uniform conical teeth, and toothed whales (odontocetes) also have identical peg-like teeth. Both are classic examples of homodont dentition.

Birds have both centrolecithal and telolecithal eggs.

Decomposers are the micro-organisms which act on the dead remains and waste products of animals and plants. They breakdown the complex substances into simpler ones that mix into the soil and are used up by the plants.