KEY

Biology 106 Dr. Dudash

Study Questions Fall 1999

Study Questions Set #9 KEY - Handed out November 29, 1999.

Due: In Lab the following week.

All answers MUST be TYPED unless mathematical computation is needed.

Use no more than one of a page of single spaced typed text.

Please answer 3 of the following questions:

1. Draw a fungus and label a hyphae, mycelium and septa.

Please draw your own and KEEP IT SIMPLE remembering that

hyphae are minute threads composed of tubular walls surrounding their plasma membrane and cytoplasm.

mycelium are a NETWORK of hyphae.

septa are the cross walls that have pores large enough to allow ribisomes. mitochondria, and nuclei to flow freely through from cell to cell.

2. What major traits separate the Chrtridioomycota, Zygomycota, Ascomycota, and Basidiomycota? Describe how they differ and provide an example of each.

Chytridiomycota: ceonphyta hyphae (lacking septa) most primitive fungal group- possible link between fungi and protists, possess a flagellated stage, ONLY fungi that does. ex., chytrids

Zygomycota: coenophyta hyphae (lacking septa), neither spores or gametes are motile, sexual spores produced by zygospores and asexual spores produced by sporangia, ex. black bread mold

Ascomycota: hyphae with septa, sexual spores are produced in sac like = ASCI, ex., morels, penicillin, cup fungi, truffles, and others.

Basidiomycota:hyphae with septa, sexual spores are produced in BASIDIOCARP, ex., classic mushroom, puff balls, smuts, shelf fungi etc.

3. What is the significance of the dikaryon stage in fungi?

The dikaryon stage in fungi is unique because 2 hyphae can exist in a diploid stage for months or years, i.e., genes in one nucleus can compensate for genes in the other, etc.

4. What is the single most important factor in understanding the evolution of body plans in animals? Please explain why. The ability to MOVE!

5. How do the 3 basic body plans differ in animals and provide an example of each?

The presence and level of development of the body cavity.

Acoelomate: no body cavity other than the digestive system, ex., flatworms, planaria, tape worms

Pseudocoelomate: body cavity develops between mesoderm and endoderm, ex., round worms, rotifers

Coelomate: body cavity completely surrounded by the mesoderm, ex., mollusks, annelids, echinoderms, chordates.

6. Discuss the 7 major evolutionary advances in the animal kingdom and provide an example of each.

1. cell specialization - cells communicate and eventually form organs.

2. triploblasty - tissue differentiation, and organs, gives rise to muscles, ability to move increased.

3. bilateral symmetry - more efficient motion, and leads to concentration of sensory cells in the anterior and eventual formation of the head.

4. internal body cavity development - increase efficiency of digestion, allows room for circulatory system, allow space foe gonad expansion, organs located in fluid filled cavity that resists pressure from the muscles.

5. segmentation - increase efficiency of locomotion, increased flexibility, closed circulatory system, and excretion more efficient as well.

6. tagmosis - reduction of segmentation by fusion of adjacent segments into a functional unit.

7. jointed appendages - develop exoskeleton, but must be shed as animal grows, facilitates feeding, movement, modifications produce antennae, mouth parts and legs.

Please refer to my handouts and lecture notes for the examples.