Question

Why did land plants lose some of the accessory pigments present in brown and red algae?

a) Accessory pigments were not beneficial for land plants.
b) These pigments were susceptible to damage from UV radiation.
c) Land plants developed more efficient photosynthetic pigments.
d) Land plants obtained these pigments from the soil.

Answer 1

Land plants lost some accessory pigents due to the development of more efficient photosynthetic pigments and evolution of protective mechanisms against UV radiation, making the accessory pigments redundant.

Step-by-step explanation:

The question of why land plants lost some of the accessory pigments present in brown and red algae addresses the evolution of plant life from aquatic to terrestrial environments. Land plants developed photosynthetic pigments such as chlorophyll which are more suited to the atmospheric conditions they face on land. Particularly, these pigments are adept at utilizing the abundant sunlight and CO2 to drive photosynthesis, without the filtering effect of water. Moreover, since the plants on land were exposed to harsher UV radiation, they evolved protective mechanisms such as the synthesis of flavonoids to shield themselves from photodynamic damage. These changes made the accessory pigments found in aquatic algae (which absorb different wavelengths of light necessary for underwater photosynthesis) less beneficial for terrestrial life, leading to their loss in land plants.