Dr. Reichler’s Bio 214  1-2pm        Print Name:________________  KEY     ________
Exam #1  June 17, 2002

    Answer each question as succinctly as possible in the space provided.  If you need more space, use the back.  If you use a drawing as part of your answer, be sure to also include a written explanation.  Each question is worth 6 pts, unless otherwise noted, for a total of 100 points possible for this exam.  Read each question carefully and don’t hesitate to ask if a question seems unclear.

1. a.  If your were looking at a plant fossil, how might you determine whether the plant you are looking at was an aquatic or terrestrial plant?
Any one of: Terrestial has presence of… Vascular tissue, Flowers, Roots, Stomata/Guard cells, seeds
Partial credit…3/6 points  Cuticle

b. In plants, what is one advantage and one disadvantage to having a cuticle?
Any one of:  Adv- keeps water in
Disadv- keeps CO2 or O2 out, can only get water from ground

c. What is different about the alternation of generations (the life cycle) of bryophytes (mosses) and angiosperms (flowering plants)?
Mosses are primarily haploid, angiosperms mostly diploid.

2. a.  What are two ways that roots increase surface area?  Why do roots need a large surface area?
Root hairs and lateral roots.  Large surface area leads to greater ability for absorption.

b. Draw a root; label and describe the function of six parts.
See Campbell et al 5th ed.  figures 35.15 and 35.16

3. a.  During plant evolution, what plant cell type was necessary for the evolution of shoots?  Explain.
Sclerenchyma, needed support AND transport.  Could also answer paranchyma, basis of all plant cell types and makes sclerenchyma.

b. How might a plant shoot exposed to strong wind be different compared to a plant shoot growing in a calm environment?
The wind-exposed shoot will be shorter, wider, sturdier, possibly with more sclerenchyma or collenchyma.

4. In very hot and dry conditions plants keep their stomata closed.  How might this inhibit the movement of water from the roots into the leaves, and aside from a lack of water, why would this decrease a plant's ability to carry out photosynthesis?
Water loss by transpiration through stomata in leaves pulls water through xylem.  If the stomata are closed, no transpiration, no pull, no movement.  Closed stomata also keep CO2 from entering, and therefore inhibit photosynthesis.

5. a.  Why are bees or other insects attracted to flowers?
Receive reward in form of sugar/nectar.
Partial credit…3/6pts color or scent.

b. There are three nuclei in pollen.  Describe what each of the three nuclei does during fertilization?
Tube nucleus-directs growth of pollen tube.  1 Sperm nucleus combines with egg to form zygote (new plant), 1 sperm nucleus combines with 2 polar nuclei to form endosperm (nutrition for embryo).

c. What function does fruit serve for plants?
Seed dispersal through reward to animals for eating fruit.

6. a.  What condition could cause an air bubble in xylem?  How might the plant get rid of this air bubble?
Any one of:  Too much transpiration for amount of water or amount of xylem.  Lack of water.
    To get rid of bubble, the xylem parenchyma transport water laterally to refill vessels/tracheids.

b. How do plants change the direction of sugar transport, and why is it necessary to change the direction of sugar transport in plants?
By changing where the loading and unloading is taking place. Any one of:   Sugar needs change …leaves in spring need sugar, in summer produce sugar.  When a flower forms it needs sugar.

c. Why would a plant without an endodermis be at a disadvantage versus a plant with an endodermis?
The plant lacking an endodermis would not be able to regulate or keep out toxins from entering vascular system of the root.

7. Why are herbaceous plants relatively small compared to woody plants?
Herbaceous plants are limited to the number of leaves based on amount of vascular tissue.  Woody plants can increase vascular tissue to increase leaf number.  Also acceptable, Wood is mostly xylem which helps support the plant.

8. Using rules 1 and 2 of Strong Inference (the parts prior to doing experiments), answer the following question:  How do plants respond to and survive in mineral-poor soil? (10pts)
(Need to propose multiple hypotheses, and then an experiment to eliminate one or more hypotheses.)  Example: Hypotheses-  Respond to lack of nutrients by increasing lateral roots.  Do not respond at all.  Respond by decreasing root area.  Respond by growing smaller.  Experiment-  Grow plants on normal and depleted soil.  Measure plant size and root size.