145 - _____ = _____ / 114 = 68.1%

Biology 332
Spring 1999

Exam II

Name_________________________

Among "fungi" you have seen three different life histories. Name the three types of life history, tell briefly the fundamental differences, and give an example "fungus" for each life history. 12 points.

Life HistoryGametophyteSporophyteExample
spor-ic multicellular multicellular Allomyces
gamet-ic spore-->gamete multicellular Saprolegnia
zygot-ic multicellular zygote-->sporocyte Mucor

In studying the fungal-like organisms, you studied a table of six divisions (phyla) of organisms. Name the divisions and tell what distinguishes each division from the others. 12 points.

Division (Phylum)Distinguishing Feature(s)
Myxomycotaplasmodium
Chytridoomycotahaustorium
Oomycotaoogonium
Zygomycotazygospore
Ascomycotaascus
Basidiomycotabasidium

You are on a trip to Bermuda and you are observing a particular species of Rhodophyte algae. While examining its distribution from the high-tide (exposed at low tide) mark to a depth of 30 meters on the flanks of the seamount, you collect specimens into netted bags and bring them to shore, making careful note of the depth at which each is collected. The specimens are one of three different colors (green, red, bluish-purple) depending upon the depth at which the alga was growing. Tell which colors are associated with each depth and explain why/how the colors change with depth. Hint: water is fairly transparent, but selectively absorbs lower-energy wavelenths. 12 points.

depthexposed at low tidecontinuous shallowin deep water
algae
color
green blue-purple red
why/how There is plenty of 680/700 nm light, no critical accessory pigments are made 680/700 nm light absorbed by water, phycocyanin and phycoerythrin made to use yellow/orange and blue/purple for PSN Even yellow/orange absorbed by water, phycoerythrin made to use blue/purple for PSN

Life Cycle
On this page, diagram the life cycle of a mushroom. Be sure to show all of the various parts of the life cycle, including reasonably-large sketches of microscopic stages. All parts of each sketch must be fully labeled. It is important to indicate processes on any arrows connecting sketches. It is important to show the chromosome condition (1N, 2N, etc.) for each sketch as well! 27 points.

basidiospore n
germination
Gametophyte
mycelium n
+/- mating types
isogamous
plasmogamy
Sporophyte? n+n
mycelium n+n
basidiocarp n+n
cap
pileus
annulus
volva
rhizomorph
lamellae
basidium n+n
karyogamy
syngamy
zygote 2n
sporocyte 2n
meiosis
sterigma
Defend the gamete condition you have assigned based on your sketches above: 2 points.
isogamous-fusing cells are the same size
Defend the life history type you have assigned in your sketches above: 3 points.
sporic-dikaryotic mycelium is sporophyte
zygotic-only truly diploid in basidium (zygote become sporophyte)
How many spores are produced from one plasmogamy event in mushrooms? 1 point
indefinitely many
How many spores are produced from one karyogamy event in mushrooms? 1 point
4
Simple Green Algae
Of all the eukaryotic algae, one genus is extremely simple. It is Chlamydomonas. It is completely unicellular, never colonial or filamentous. Vegetative haploid cells can reproduce by mitosis, but this is not true of any diploid cells. Chlamydomonas reinhardtii is isogamous and syngamy is instantaneously complete. Using this information, sketch and label the life cycle of Chlamydomonas reinhardtii below: 14 points
meiospores 1n
mitosis
"gametophyte"
isogametes
+/- mating types
syngamy
zygote 2n
zygotic
sporocyte 2n
meiosis

Chlamydomonas braunii is just like C. reinhardtii, except for the fact that it is anisogamous. Redraw whatever sketch(es) must be revised in the life cycle. 4 points
both motile; female large, male small
Chlamydomonas coccifera is just like C. reinhardtii, except for the fact that it is oogamous. Redraw whatever sketch(es) must be revised in the life cycle.
female = large, immotile; male = small, motile

Complex Green Algae
Not all algae are as simple as Chlamydomonas. Perhaps a more typical example is the common sea lettuce, Ulva lactuca. Sea lettuce is commonly observed in the wrack on the beach, but it is found naturally anchored in shallow tide pools. It is anisogamous, sporic, heterothallic and completely isomorphic. Gametes are biflagellate; two fundamentally-different motile cells in the sexual cycle are quadriflagellate. Assume there is no asexual reproduction. Using this information, sketch and label the life cycle of Ulva lactuca below. 19 points.

male gametophyte
female gametophyte
heterothallic
holdfast
1n
female gametangium
male gametangium
biflagellate female gamete
biflagellate male gamete
anisogamous
syngamy
quadriflagellate zygote
2n
sporophyte
holdfast
isomorphic
sporangium
sporocyte
meiosis
quadriflagellate meiospores

Bryophytes
In the following grid, make and label a sketch of each part of the life history of a moss. 25 points total.
haploiddiploid
spore 2 points
spore wall
spore wall
nucleus
zygote 2 points zygote
archegonium
(calyptra)
gametophyte 3 points
"leaf"
"stem"
rhizoid
sporophyte 3 points
sporangium
seta
foot
gametangia 9 points
archegonium
neck
neck canal cells
egg
venter
antheridium
sterile jacket
spermatogenic tissue
stalk
sporangium 6 points
operculum
peristome teeth
diaphragm
columella
sterile jacket
sporocytes-->

9 points:
What stage of the life history of a moss indicates an alga-like ancestor? protonema
What characteristic of gametangia and sporangia in mosses shows good adaptation to life on land? sterile jacket
What characteristic of moss gametophytes is adaptive for terrestrial existence? hydroids and leptoids
What characteristic of moss sporophytes is adaptive for terrestrial existence? cutin and stomata
What structural characteristic of moss spores is adaptive for terrestrial existence? sporopollenin and wind dispersal
What characteristic of hornwort sporophytes expands their reproductive potential? intercalary meristem
What characteritic of hornwort sporophytes is most-adaptive for independence from the gametophyte? photosynthesis
What is the gamete condition found in all true plants (bryophytes and vascular plants)? oogamous
What is the kind of life history found in all true plants (bryophytes and vascular plants)? sporic



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