In what ways does Chlaydomonas resemble sperm cells

24 Jun In what ways does Chlaydomonas resemble sperm cells

Question
6A

1. In what ways does Chlaydomonas resemble sperm cells?

2. For the most part its life cycle, Chlamydomonas exist as a free-living haploid cell. It reproduces by mistois. During adverse environmental conditons, the cells produces nearly identical gametes. The gametes of two different mating strains join to form a diploid zygote which survives through the deteriotorating conditions. When conditions improved, the zygote undergoes meiosis to produce haploid spores. The spores germinate to form new cells.

Based on the description above, make a diagram of the life cycle of the Chlamydomonas life cycle.

Is this an alternation of generation life cycle? _____ Explain

What environmental conditons might be considered adverse for the Chlamydomonas?

3. What is the shape of the chloroplast in Chlamydomoas?

4. What is the function of the chloroplast in Spirogyra?

5. Spirogyra enters its sexual reproductive phase when environmental conditions are poor. The zygospore that is formed survives throught the adverse conditions and forms spores by meiosis when conditions improve. A spore undergoes mitosis to produce new haploid filament.

Based on the description above, make a diagram of the Spirogyra life cycle.

Which portion of the Spirogyra life cycle is multicellular: the haploid portion or the diploid portion?

In what ways is the life cycle of the Spirogyra similar to that of Chlamydomoas?

6. Describe the motion of the Volvox.

What causes this motion?

7. Why is the Volvox considered a colonial organism?

8. Where is Ulva normally found?

9. How many cell layers does Ulva have?

10. Higher level teresterial plants have vascular systems for transporting materials through the plant. Based on microscope observations of the interior of the stem of Ulva, do you see any evidence of cells or tissues that might form a vascular system? _____ Are there any openings through which gases can move into and out of the thallus?

11. Could you tell whether the Ulva you saw on demotration today is the sporophyte or gametophyte? Why or why no?

12. Given your observations of these algae, what characteristics of the chlorophytes would you say ensure that adequate exchange of water and minerals can occur between the algae and their environment?

6B

1. Which portion of the moss life cycle is free-living? ______ How could you tell this by looking at the plant?

2. What stage of the life cycle produces the gametes? ________ What stage of the life cycle produces the spores?

3. Are spores haploid or diploid?

4. What is the fate of the spores?

5. Moses typically do not grow to be very tall at all and are usually found close together. Based on your observations of the plant, why do you think this is?

6. Moses typically grow along the banks of streams, or in other places where there is moisture. Based on what you know about how mosses reproduced, speculatae as to why these habitats would be evolutionary advantageous?

6C

1. In what ways does the morphology (size and shape) of the sporophyte differ from that of the gametophyte in ferns?

2. Which generation of the fern life cycle (the sporophyte or the gametophyte) are you more likely to notice when when walking in the woods?

3. In what ways is the dispersal of sperm similar in ferns and mosses?

4. Explain why fossil fuels are a nonrenewable resource?

6D

1. Desribe the structure of the leaves in a pine tree.

· How is the structure of the leaves related to the requirement that terrestrial plants must conserve water?

· How are the leaves arranged on the stem

· Are the cells of the leaves haploid or diploid?

· Is a mature pine tree part of the haploid or diploid portion of its life cycle?

2. Desribe the difference in appearance between pollen cones and ovulate cones?

What important process occurs in the sporangia of the cones?

3. Are microsporocyes haploid or diploid?

Are the microspores haploid or diploid?

4. You probably noticed that pollen grains have wings on them. What is the purpose of the wings?

6E

1. Suppose that you decide to take a stroll through campus in the springtime, looking at plants. You come across a mature oak tree and some yellow-sh green oak pollen nearby on the ground.

Is the oak tree haploid or diploid?

Is the oak pollen haploid or diploid?

2. Which phase of the angiosperm life cycle lasts longer: the gametophyte or the sporophyte?

3. Is an angiosperm sporophyte autotrophic or is it heterotrophic?

4. Angiosperms that are pollinated by animals generally have brightly colored petals, while those pollinated by wind don’t. Spectulate as to the evolutionary advantage of brightly colored petals on plants that have them?

5. What characteristics of the pollen grains and embryo sacs make them beneficial adaptations for terrestrial plants?

6. What is the food source for the embryo while it is inside the seed?

When does this food source cease being a source of nutrition for the growing sporophyte?