Seaweed (General)
What broad domain/organism type do seaweeds belong to?
Seaweeds are eukaryotic, mostly multicellular protists (marine algae or macroalgae).
What is the dominant structural component in the cell walls of green algae?
Cellulose.
What are three notable examples of brown seaweeds?
1. Kelps
2. Rockweeds (Fucus)
3. Sargassum
What material accumulates within the thallus of coralline red algae?
Calcium carbonate (CaCO3)
What are the three main ecological groups of marine flowering plants?
1. Seagrasses
2. Salt-marsh plants
3. Mangroves
In seaweed morphology, what is the 'thallus'?
The complete body of a seaweed.
What chemical compound is incorporated into the thallus of calcareous green algae?
Calcium carbonate (CaCO3)
What preferred environmental conditions are characteristic of brown seaweeds?
Shallow, cold ocean waters.
What reserve carbohydrate do red algae store?
Starch (Floridean starch).
How is seagrass pollen transferred for fertilization underwater?
It is carried directly by water currents.
What is the function of a seaweed pneumatocyst?
It is a gas-filled bladder that keeps the photosynthetic blades floating near the water surface to maximize sunlight exposure.
How do green seaweeds store excess energy?
They store energy as starch.
What key chemical compounds compose the cell walls of brown seaweeds?
Cellulose and alginates.
What major cell wall chemicals are extracted commercially from red seaweeds?
Agar and carrageenan.
What defining anatomical features distinguish flowering plants (angiosperms) from seaweeds?
Flowering plants possess true leaves, stems, roots, and vascular conducting tissues (xylem and phloem).
What essential plant structures are completely absent in seaweeds?
True leaves, stems, roots, and vascular conducting tissues (veins).
Which photosynthetic pigments are present in green seaweeds?
Chlorophylls a and b, along with carotenoids (identical to true land plants).
Which photosynthetic pigments give brown seaweeds their distinct coloration?
Chlorophyll a, chlorophyll c, and fucoxanthin (a brown accessory pigment).
Which photosynthetic pigments give red algae their characteristic color?
Chlorophyll a, phycobilins (phycocyanin and phycoerythrin), and carotenoids.
What alternation of generations is characteristic of marine flowering plants?
Alternation of a dominant diploid sporophyte phase with minute male and female gametophytes.
How does a seaweed holdfast differ functionally from true plant roots?
A holdfast serves strictly for physical anchorage and lacks vascular veins to absorb or transport water and nutrients.
What ecological role do calcareous green algae play in tropical marine ecosystems?
They provide major calcareous deposits that contribute to the structural framework of coral reefs.
What are the primary food storage reserves in brown algae?
Laminarin and oils.
How many generational stages are involved in the sexual life cycle of many red algae?
An alternation of three generations.
Out of over 250,000 global species of flowering plants, how many are adapted to marine environments?
Only a very small minority (e.g., ~60 species of seagrasses and ~80 species of mangroves).