Key to Lab manual 7. Algae and Protists
1. Why should the term algae be one of convenience rather than one with definite technical connotations?
- The term algae refers to any organism (that is not a plant) capable of carrying out photosynthesis. Because many different and diverse organisms possess this ability, trying to group these individuals based solely on their ability to photosynthesis would not be an accurate representation of their phylogeny.
2. Why could conjugation in Spirogyra be considered a form of isogamy?
- Isogamy refers to the condition of having two gametes that appear identical. In
Spirogyra the two strands that ultimately conjugate (or sexually reproduce) are identical, and the entire cellular contents of one strand are transferred to the other.
3. What is oogamy?
- Oogamy refers to the condition of having two gametes that are distinctly different from one another. The egg, or female gamete, is larger and sessile (meaning it has no flagella with which to move around). The male gamete is usually flagellated and much smaller than the female gamete.
4. How could you identify Spirogyra if you had no microscope?
- By feel—often filaments of Spirogyra rise to the surface of ponds or stagnant water and are slimy to the touch.
5. What is one possible function of a zygospore? When would algae most likely produce these?
- The zygospore is basically a dormant zygote encased in a thick cell wall. It functions to protect the zygote during times of environmental stress or limited nutrient availability.
6. Why are the cyanobacteria considered the most primitive algae?
- Because they are not eukaryotic, and therefore are the most distantly related to land plants, or the organism that ultimately evolved from what we think of as algae.
7. What is the major method of reproduction in the cyanobacteria?
- Fission, a type of asexual replication common in prokaryotes.
8. How does Chlamydomonas differ from Euglena in appearance?
- Chlamy is biflagellated, Euglena has one main flagella.
- Chlamy has one large cup-shaped chloroplast while Euglena has several smaller ones.
- Chlamy is rounder and looks like a horseshoe whereas Euglena is more elongated.
9. Does the species of Euglena seen in class have a rigid or flexible pellicle?
- Our Euglena species was dead in class, so you didn’t have to answer this question. A pellicle is a thin layer that functions to support the cell membrane in some protists.
10. How can diatoms be recognized easily?
- They are bilaterally or radially symmetrical.

- Their cell walls contain silica and are rigid.
- They are small and always single celled.
Key to Lab Manual 8. Fungi (Part I)
1. Slime molds are sometimes studied in zoology courses. List two features of slime molds that could be considered animal-like and two plant-like features.
- Slime molds are animal-like in that they are motile and engulf microorganisms for nutrition. They are plant-like in that they form a “vegetative phase” that is non-motile and produces spores.
2. How do the slime molds differ from the true fungi?
- There are several differences between slime molds and “true fungi,” but the manual is referring to the body plan of slime molds versus true fungi. Slime molds do not possess the extensive network of branching hyphae (mycelium) that true fungi possess.
3. Which alga, studied recently, has a pattern of reproduction similar to that of
Saprolegnia ?
- It is similar to the algal genus Vaucheria in that it produces both male and female gametes that are distinct from one another on the same filament.
4. In Rhizopus, the sporangia are produced at the end of sporangiophores. What is a possible benefit of this arrangement?
- Spore dispersal—the further from the main body of the “fungi,” the better the chance to be disseminated by air currents.
5. What is the difference between a parasite and a saprophyte?
- A parasite saps nutrients from a live host, while a saprophyte uses the nutrients still available in dead tissues.
6. Saprolegnia was said to be homothallic; Rhizopus was said to be heterothallic. What do these two terms mean?
- These terms refer to distribution of male and female reproductive structures present on a species of fungi. Homothallic fungi produce male and female reproductive structures on the same individual, while heterothallic fungi produce male structures on one strain, and female structures on another.
7. How does spore production of Rhizopus differ from conidia production in Aspergillus or Penicillium ?
- Spores produced by Rhizopus are a result of sexual reproduction. The conidia produced by Apsergillus and Penicillium are a result of asexual reproduction.
8. How are conidia and spores similar?
- They are similar in that they are both presented for dissemination on long stalks and both give rise to new individuals.

Key to Lab Manual 9. Fungi (Part II).
1. Are ascospores haploid or diploid?
- Haploid
2. What type of nutrition do these fungi have, i.e. parasitic or saprophytic?
Microsphaera : Parasitic
Sordaria : saprophytic
Claviceps : parasitic
Puccinia : parasitic
3. How do the asci of Microsphaera and Sordaria differ in appearance?
Microsphaera asci are closed and form a spherical fruiting body (Cleistothecium).
Sordaria asci form flask-shaped fruiting body with a pore at the tip (perithecium).
4. Suggest a method for controlling wheat rust without resorting to fungicides.
- There are several possible answers here, but the best would be to avoid growing barberry plants near your wheat crop—without the alternate host to complete their life cycle, Puccinia would not be able to proliferate on wheat.
5. How can uredospores easily be differentiated from teliospores?
- By determining their location respective to the epidermal layer of their host plant— uredospores are found just under the epidermal layer forming “blisters” on the surface of the plant, while teliospores grow on the outside surface of the epidermis. Also, teliospores appear black and have very thick cell walls when compared to uredospores.
6. Why is it a hopeless task to try controlling mushrooms in a lawn by picking the basidiocarps?
- Because basidiocarps are merely the fruiting bodies of the larger and more extensive fungal network (mycelium) that lives in the upper layers of soil. Getting rid of the mushrooms has barely any effect on the fungus’s viability.
7. How does a basidium compare to an ascus in the way the spores are produced and the number of spores produced?
- A basidium produces sexual spores externally and is most often found on a larger fruiting body called the basidiocarp. They produce heaps of spores.
- An ascus is a sac-like structure that produces sexual spores. These structures typically produce only eight spores (ascospores)—much fewer than the basidia.
8. People often have very poor success when they try to transplant native wildflowers to a home garden. Can you think of one reason for this based on the information obtained in this exercise?
- Mycorrhizae are the beneficial fungal community associated with the roots of certain plants. These fungi allow plants to absorb more nutrients and water from the soil. If a native wildflower is transplanted to a home garden, the fungal associations it had in the wild might not be available in its new environment, severely limiting its growth and success.