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| Give examples of the roles animallike protists play in the living world. | Some live symbiotically in other organisms; some recycle nutrients by breaking down dead organic matter; others in the seas & lakes are eaten by tiny animals that serve as food for larger animals. |
| Why are Trichonympha important? | The enzyme cellulase is produced by it, and it helps break down the chemical bonds in cellulose so termites can digest wood. |
| What is the common name for plantlike protists? | Algae; some scientists put those closely related to plants in the kingdom Plantae. |
| What problem do water algae have and how has evolution addressed this ? | In deep water, there is a shortage of light, so they have developed different forms of chlorophyll to deal with this. |
| Define "accessory pigments". | It's a compound other than chlorophyll that absorbs light at different wavelengths than chlorophyll. Thus, algae can have a wide range of colors. |
| What are the most common characteristics of Euglenophytes? | They are plantlike protists that have 2 flagella but no cell wall. Euglenas are excellent swimmers. The eyespot (near gullet) helps the organism find sunlight for photosynthesis. If there's no sunlight, they live as heterotrophs. They have a pellicle (intricate cell membrane), allowing euglenas to crawl through mud. They reproduce asexually by binary fission. |
| What are the main characteristics of Chrysophytes? | This phylum includes yellow-green algae & golden-brown algae. They have bright yellow pigments and gold-colored chloroplasts. Some have cell walls containing carbohydrate pectin instead of cellulose; some have both. They store food in oil form, not starch; they reproduce asexually & sexually. Most are solitary; some form threadlike colonies. |
| Describe the phylum Bacillariophyta, or diatoms. | They produce thin, delicate cell walls rich in silicon; walls are shaped like 2 sides of a petri dish or flat pillbox; one side fits snugly into the other. Cell walls have fine lines & patterns that almost seem to be etched into their glasslike brilliance. (See 507) |
| Give the main characteristics of Dinoflagellates. | 1/2 are photosynthetic; 1/2 are heterotrophs; they have 2 flagella; most reproduce asexually (binary fission); many are luminescent, giving the phylum the name of Pyrrophyta (fire plants). |
| What role does phytoplankton play in ecology? | Phytoplankton conduct about 1/2 of the photosynthesis occurring on Earth. This provides a direct source of nourishment for organisms as diverse as shrimp & whates. |
| What effect do "blooms" have ecologically? | Great blooms of Gonyaulax & Karenia (red tides) produce potentially dangerous toxins; eating shellfish from water infected with red tide can cause serious illness, paralysis, and even death in humans & fish. Algal blooms also deplete water of nutrients; as these dead algae decompose, they rob water of oxygen, choking fish & invertebrates living there. (see 509). |
| How can red algae (phylum Rhodophyta) able to live at great water depths? | They are efficient in harvesting light energy; they contain chlorophyll a and pigments called phycobilins. |
| What are phycobilins? | They are accessory pigments found in red algae that is especially good at absorbing blue light. |
| What are the main characteristics of red algae? | They're multicellular; they lack flagella & centrioles; they help form coral reefs; they maintain equilibriums of the coral ecosystem, providing nutrients from photosynthesis nourishing coral animals; coralline red algae provide much calcium carbonate helping stabilize growing coral reefs. |
| What gives most brown algae their dark, yellow-brown color? | They contain a combination of fucoxanthin (pigment) and chlorophylls a & c. |
| What is the larges and most complex of algae? | brown algae |
| What is the largest alga? | Giant kelp (see 511 for other types) |
| List some main characteristics of green algae. | Photosynhthetic pigments; cellulose in cell walls; chlorophyll a & b; store food in form of starch; found in fresh & salt water; most are single cells; others form colonies; a few are multicellular. |
| Give the major characteristics of unicellular green algae Chlamydomonas. | Grow in ponds, ditches, wet soil; small egg-shaped cell with 2 flagella and 1 large, cup-shaped chloroplast; in the base is a region that synthesizes & stores starch; 2 small contractile vacuoles. See picture pg. 512. |
| How are filaments related to colonial green algae? | Filaments (long threadlike colony formed by many green algae) are long threadlike colonies. (See 512) |
| What characteristics does Ulva, or sea lettuce, have? | They're multicellular green marine alga. It contains several specialized cell types; it's 2 cells thick, but it survives in pounding of waves on the shores where it lives attached to rocks. |
