Seaweed

Table 1. Comparison of Green, Brown, and Red Algae

21 points, 1 pt. each cell

Algae Type	Brown	Green	Red
Division	Phaeophyta	Chlorphyta	Rhodophyta
Specific Example	Egregia menziesii	Codium fragile	Chondracanthus exasperatus
Form(s)	Large and elaborate	Single celled, or small	simple and branched filaments, fleshy plants, and sheets.
Pigment(s)	light olive green or golden, to very dark brown	light olive green	they may appear purple, brown, green, or yellow
Habitat(s)	intertidal or shallow subtidal zone,	shallow intertidal zone	deeper waters than other algae. Red algae also grow in the intertidal zone.
Human Uses	sold as a fertilizer for terrestrial agriculture.	Some common species of green algae such as Ulva (sea lettuce), and Enteromorpha(green string lettuce) are used as food products.	Carrageenan is an important ingredient in toothpaste and many milk products, such as ice cream and chocolate milk
Useful Substances	Fucans are the slimy stuff found on kelps, and have potential medicinal uses.		Agar has many scientific applications in microbiology, biotechnology, and criminology, and is also used in the packaging of canned meats

 Access the Miracle website and answer the following questions about diatoms.

What are diatoms?

Diatoms are photosynthesising algae

To what division and class diatoms assigned?

Division Chrysophyta, Class Bacillariophyceae

What are the major characteristics of diatoms?

 Diatoms are commonly between 20-200 microns in diameter or length. The cell may be solitary or colonial 

Describe the life cycle of a diatom. 

When a cell divides each new cell takes as its epitheca a valve of the parent frustule, and within ten to twenty minutes builds its own hypotheca; this process may occur between one and eight times per day.

List five human uses for diatoms. 

Diatoms reduce high blood pressure, clean the human colin, lowers cholesterol, reduce one's weight, ad strengthen hair, nails, gums, and teeth.

Explain the role of diatoms in the carbon cycle.

They reduce the amount of CO2 in the air during photosynthesis.