Question

The land plants are probably descendants of which of these groups?

a. green algae

b. red algae

c. brown algae

d. angiosperms

Short answer

Option (a) Green Algae.

The land plants are descendants of green algae.

Step-by-step solution

Step 1. Introduction

Information on green algae :

• Algae are eukaryotic organisms with the ability to perform photosynthesis.
• There are mainly three types of algae: Brown algae or Phaeophyta, Red algae or Rhodophyta, and Green Alage or Chlorophyta.
• The Green Algae contains chlorophyll a and b in their chloroplasts and hence, are green in color.
• Chlamydomonas and Cladophora are common examples of green algae.

Step 2, Reason for correct option 

Explanation of how green algae evolved into land plants.

• Green algae were predominantly aquatic with the absence of vascular tissues.
• There are mainly three groups of green algae i.e., colonial algae containing both unicellular and multicellular algae in their colonies following that the purely multicellular algae with long or flat unicellular filament and finally charophytes which are multicellular with thick filaments and cell plates.
• Evolution being a stochastic gradual process depends on adaptation and change.
• Apart from all the common ancestral traits shared by green algae and land plants the evidence also suggests that roughly 410 million years ago some green filamentous green algae landed on solid grounds.
• The most closely related algae to that of land plants are streptophyte.

Hence, option (a) Green Algae is correct.

Step 3. Reason for incorrect options

All the other options namely red algae, brown algae and angiosperms lacks similarities in traits and features to that of land plants, such as:

• Red Algae does not contain Chlorophyll a and b.
• Brown algae contain Chlorophyll a and c along with fucoxanthin.
• Angiosperms being the advanced land plant, dos did not fit the criteria of descendants.

Hence , these options are incorrect.