Q29.1-2CC. - Campbell Biology

Question

Identify four derived traits that distinguish plants from charophyte green algae and facilitate life on land. Explain.

 

Step-by-Step Solution

Answer

Although the Charophytes are similar in traits to plants, specific characteristics differentiate plants from Charophytes. These traits are the presence of stomata and cuticles, rigid spore walls, and multicellular embryos.

Step 1: Presence of stomata

The plant species has the presence of stomata that controls the exchange of gases in the plants. Due to dissolved inorganic carbon in aquatic water systems, charophytes do not need the stomata for the exchange of gases.

Step 2: Presence of cuticles

In plants, cuticles reduce water loss as they form a layer on the leaves, flowers, fruits, and other structures. Charophytes do not possess cuticles as they are already present in the water bodies; they do not suffer from water loss.

Step 3: Spore walls

The spore walls present in the plants are rigid. They are toughened by the presence of sporopollenin and thus help in protection from the harsh environment. The Charophytes do not have specific cell walls, so the sporopollenin is absent.

Step 4: Multicellular embryos

Plant embryos are multicellular as they undergo several mitotic cell divisions to form a spore. The Charophytes divide both sexually and asexually, most specifically by asexual reproduction.

Sexual reproduction in Charophytes occurs by zygotic meiosis, so the embryo is not multicellular. Asexual reproduction occurs through the process of fragmentation. Thus, due to specific reasons, the Charophytes differ from plants despite a close ancestral relation.