6. (15 points total, 3 points each) Respond to each of the following:
a. Which cell wall compounds derived from red and brown algae are used thicken foods and cosmetics? What properties do these compounds provide to the algae in their native habitats?
b. Brown algae are not considered the most probable evolutionary ancestors of terrestrial plants even though they have complex bodies that resemble land plants in some ways. List three such morphological features and their analogous structures in land plants.
c. (6 points total, 3 points each) Describe two differences and one similarity between two of the following pairs of organisms:
- Zygomycetes and Basidiomycetes
- Diatoms and Red Algae
- Mosses and Ferns
d. List one advantage and two disadvantages to photosynthetic autotrophs of the terrestrial versus the aquatic environment.
7. (6 points) Contrast the "alternation of generations" that is common to all terrestrial plant life cycles with the general life cycle shared by fungi in the ascomycetes and basidiomycetes
8. (9 points total, 3 points each) Explain each of these observations:
a. Red algae have been found growing at depths greater than 250 meters in some areas of the Carribean Sea while green algae are not found deeper than 25 meters in the same waters.
b. Aster seedlings planted in soil taken from their native fields grew much faster than others planted in the same soil that had been sterilized by autoclaving (high temperature and pressure).
c. Lichens are technically not individual organisms.