123 - ____ = ____/____ = ____.__

Spring 1997
Biology of Plants

Exam IV

Name_____________________

Evolution of female reproductive coverings. In this course we have traced this evolution from isogamete, to anisogamete, to egg, to egg in oogonium, to egg in archegonium as we went from algae through fungi to bryophytes and ferns. It is a pathway of coverage in which the female reproductive structures that once were free-living swimming forms have evolved into sessile forms contained in layers of coverage. Think about a very advanced flowering plant and list the coverings it has around its egg in order from the outside to the inside. You only need to write the name of each layer on the way in! 6 points

Outermost layerInnermost layer
receptacleovary wallintegumentnucellusmegaspore wallsynergidegg

Evolution of megagametophytes. Describe what has been lost from the megagametophyte during evolution of the three heterosporous life histories. You do not need to mention anything but the gametophyte itself. Starting with a moss female gametophyte: thallus, rhizoid, "stem", "leaf", archegonium, egg tell what has been lost at each step in evolution (no need to repeat losses). 4 points.

Selaginella lost the: "stem" and "leaf"

Gymnosperms lost the: rhizoid

Angiosperms lost the: archegonium

Here diagram the mature megagametophyte of an angiosperm, showing all of its cells. Next to each named cell, write the ultimate fate of that cell. 12 points.

Diagram:           Name of cell(s):           What they do or become:

Evolution of microgametophytes. Describe what has been lost from the microgametophyte during evolution of the three heterosporous life histories as you did with a previous question. Starting with a moss male gametophyte: thallus, rhizoid, "stem", "leaf", antheridium, motile sperm, tell what has been lost at each step in evolution (no need to repeat losses). 5 points.

Selaginella lost the: "stem" and "leaf", and rhizoid

Gymnosperms lost the: antheridium

Angiosperms lost the: motility of sperm


Here diagram the mature microgametophyte of an angiosperm, showing all of its cells. Next to each named cell, write the ultimate fate of that cell. 6 points.

Diagram:           Name of cell(s):           What they do or become:

5 points:
Name the process of moving this microgametophyte
toward a female structure in both gymnosperms and angiosperms.
pollination
What protects the microgametophyte against desiccation
(drying out) during its travel toward the female structures?
pollen wall
What is unique about the syngamy event in angiosperms? it is double
What cell and tissue results from syngamy that was not
seen in either gymnosperms or Selaginella syngamy events?
endosperm
What is the ploidy of this unique cell and tissue? 1N       2N       3N       4N

Diagram a longitudinal section of a flower and label it as completely as you can. 20 points.

pedicel, receptacle, sepal, calyx, perianth, petal, corolla, filament, anther, stamen, androecium, carpel, ovary, style, stigma, gynoecium, pistil, locule, ovule, pollen grain


In the following table, compare the structure and organization of primitive and advanced flowers. 20 points.
Primitive FlowerAdvanced Flower
radialbilateral
many partsfewer parts
elongate axisshort axis
bisexualunisexual
beetle pollinatedbee, wind pollinated
hypogynousepigynous
superior ovaryinferior ovary
large flowerstiny flowers
single flowersgathered into head
all flowers samedivision of labor

You have learned about extensive free-nuclear stages in both Pine and Angiosperms. 4 points.

What has to happen for a cell to become free-nuclear? mitosis without cytokinesis

What is the major free-nuclear stage in Pine? megagametophyte

What is the major free-nuclear stage in Angiosperms? endosperm

Make a diagram of the two kinds of seeds. Label completely! 14 points.

Gymnosperm seedAngiosperm seed
integument, nucellus, megagametophyte, embryo integument, nucellus, endosperm, embryo cotyledon, shoot apex, root apex cotyledon, shoot apex, root apex

There are three distinct ways to classify a fruit. Tell the main categories of each of them. 7 points.
Ways to ClassifyMain Categories (Types)
OriginSimpleAggregateMultiple
CompositionTrueAccessory
DescriptionFleshyDry


Heterosporous Life Cycle Diagram. In this last part of the course you have learned the heterosporous life cycle. Arrange the 20 labels provided to you on this page to demonstrate your understanding of this special life cycle. Note: you may want to turn the page sideways (but do not have to) and you should know that the labels cannot be repositioned! Once stuck down, you are stuck with their position! So plan carefully! 20 points.