Question

Aquatic ancestry of Bryophytes is best indicated by
A. Parenchyma in stem
B. Flagellated male gametes
C. Aerenchyma in stem
D. All of the above

Answer 1

Hint: Bryophytes are a division of the plant kingdom that consists of Mosses, Liverworts and Hornworts. They lack vascular tissues and can survive on land as well as in water. They lack flowers and seeds formation but gametes are formed. The fusion of gamete for sexual reproduction occurs only through water.

Complete answer: Bryophytes are a special kind of plant-like structures that can live both in water and on land. Most of them are terrestrial but for reproduction, they depend on water. They form the simplest and primitive group of land plants. They are found in temperate to tropical regions of the world. Indian regions like Shimla, Dalhousie, and Darjeeling show luxuriant growth of Bryophytes. The body of bryophytes resembles plants but lacks true differentiation. Flower and seed formation is absent. But bryophytes reproduce sexually through gamete formation. They have distinct male and female gametes. Now, the aquatic ancestry of Bryophytes is indicated by their dependency on water for gamete fusion. The male gametophyte of bryophytes is flagellated to swim through water to reach the female gamete. The female gametes stay enclosed in archegonia. This characteristic of flagellated male gametes links the migration of bryophytes from aquatic to terrestrial habitats. Another feature that ensures this link is the development of gametangia. Gametangia provide protection to gametes as they need to be exposed to water. These survival points relate bryophytes to aquatic ancestry. Thus, the amphibious nature and flagellated antherozoids or male gametes of bryophytes are strong indications for their aquatic ancestry behaviour.
So, option B is the correct answer.

Note: Bryophytes are primitive of all land plants. Most of them are terrestrial but still depend largely on the moisture in their surrounding for fluid transport in the body. Some of them are found in freshwater but they are not present in the sea. Bryophytes were first considered to be related to algae, fungi, and lichens.