Which algal group includes kelp, gulfweeds, and rock weeds?

Which algal group includes kelp, gulfweeds, and rock weeds?

• A. Brown Algae
• B. Red Algae
• C. Green Algae
• D. Cyanobacteria

Answer: (A)

Brown algae are the group that includes kelp, gulfweeds, and rockweeds. Their distinctive brown color comes from the pigment fucoxanthin, which works with chlorophyll a and c. These algae are primarily marine, often thriving in temperate, nutrient-rich coastal waters, and some reach impressive sizes, like giant kelp that can form underwater forests. They have a characteristic body plan with a holdfast that grips rocks, a stem-like stipe, and blade-like fronds, sometimes with gas-filled bladders that help them float toward the light. They store energy as the carbohydrate laminarin and sometimes mannitol, rather than starch. This set of traits differentiates brown algae from red algae, green algae, and cyanobacteria. Red algae are typically smaller and adapt to different light conditions with phycoerythrin, green algae include many species related to land plants and usually inhabit shallower, well-lit areas, and cyanobacteria are prokaryotic organisms, not true algae. Therefore, kelp, gulfweeds, and rockweeds all belong to brown algae.

Brown algae are the group that includes kelp, gulfweeds, and rockweeds. Their distinctive brown color comes from the pigment fucoxanthin, which works with chlorophyll a and c. These algae are primarily marine, often thriving in temperate, nutrient-rich coastal waters, and some reach impressive sizes, like giant kelp that can form underwater forests. They have a characteristic body plan with a holdfast that grips rocks, a stem-like stipe, and blade-like fronds, sometimes with gas-filled bladders that help them float toward the light. They store energy as the carbohydrate laminarin and sometimes mannitol, rather than starch.

This set of traits differentiates brown algae from red algae, green algae, and cyanobacteria. Red algae are typically smaller and adapt to different light conditions with phycoerythrin, green algae include many species related to land plants and usually inhabit shallower, well-lit areas, and cyanobacteria are prokaryotic organisms, not true algae. Therefore, kelp, gulfweeds, and rockweeds all belong to brown algae.