Page 20 - Kingdom Protist

Figure 3.8 The red photosynthetic
pigments allow the red algae to
live in deep water and still use
sunlight to photo synthesize.

Most red algae in phylum Rhodophyta are multicellular. Look at Figure 19.20
to see how red algae got their name. These organisms contain red photosynthetic
pigments called phycobilins that give them a red color. These pigments enable the
red algae to absorb green, violet, and blue light that can penetrate water to a depth
of 100 m or more. This allows red algae to live and photosynthesize in deeper water
than other algae. Some red algae also contribute to the formation of coral reefs.
The cell walls of the red alga Coralline contain calcium carbonate. The calcium
carbonate binds together the bodies of other organisms called stony coral to form
coral reefs.

Figure 3.9 The life cycle of many
algae, including the sea lettuce Ulva
shown here, includes an alternation
between a diploid and haploid
generation. Alternation of
generations also is found in
members of both the plant and fungi
kingdoms.

The life cycles of many algae are complex. Algae can alternate between spore-
producing forms and gamete producing forms. They can reproduce sexually as well
as asexually. Green algae also reproduce asexually through fragmentation a process
in which a multicellular individual breaks into separate pieces and each grows into
an individual organism.

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