Page 14 - Kingdom Protist

Plantlike Protists PART 3

The group of protists called algae

(singular, alga) is considered plant-like
because the members contain photosynthetic
pigments. Recall from Chapter 8 that
photosynthetic pigments enable organisms to
produce their own food using energy from the
Sun in a process called photo synthesis. Algae

differ from plants because they do not have

roots, leaves, or other structures typical of
plants. The light-absorbing pigments of algae

are found in chloroplasts. In many algae, the
primary pigment is chlorophyll—the same

pigment that gives plants their characteristic
green color. Many algae also have secondary

pigments that allow them to absorb light
energy in deep water. As water depth

increases, much of the sunlight’s energy is Giant kelp (Macrocystis pyrifera)
absorbed by the water.

These secondary pigments allow algae to absorb light energy from
wavelengths that are not absorbed by water. Because these secondary pigments
reflect light at different wavelengths, algae are found in a variety of colors, as shown
in Figure 3.1

• Figure 3.1 Algae
vary in color because
they contain different
light-absorbing
pigments.

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