134 - ____ = ____/____ = ______.__

Spring 1998
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 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. Tell what layers are added in each step in evolution...5 points.

Selaginella added the: megaspore wall

Gymnosperms added the: megasporangium = nucellus and integument

Angiosperms added the: ovary wall and receptacle

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 (write each word only once among the blanks below). 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 (write each word only once among the blanks below). 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:

7 points:
Name the process of placing this microgametophyte
in/on a female structure in both gymnosperms and angiosperms.
pollination
What is the ultimate placement of the microgametophyte in gymnosperms?micropyle
What is the ultimate placement of the microgametophyte in angiosperms?stigma
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?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

Label this longitudinal section of a flower. 16 points

The flower above is:       epigynous perigynous       hypogynous

The ovary above is:       superior       inferior

The pistil shown above is:       simple       compound


In the following table, compare the structure and organization of primitive and advanced flowers. 20 points
FeaturesPrimitive FlowerAdvanced Flower
symmetryradialbilateral
leaf numbermany partsfewer parts
axis lengthelongate axisshort axis
sexualitybisexualunisexual
pollinatorbeetle pollinatedbee, wind pollinated
flower -gynyhypogynousepigynous
ovary positionsuperior ovaryinferior ovary
flower sizelarge flowerstiny flowers
flower groupssingle flowersgathered into head
division of laborall 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
cotyledon
shoot apex
root apex
integument
nucellus
endosperm
embryo
cotyledon
shoot apex
root apex


You are on a tropical safari and you find a fruit in the jungle. The spherical object is completely solid, though it looks like it is made of many sections. The fruit appears to be soft and juicy. On the surface you find each section of the fruit has a little ring of five tiny green leaf-like structures. In the center of each ring of leaf-like structures are some dried up threads with a swollen bag-like end. In the middle of these is a very tiny scar. You try to cut through the fruit, but each section of it has a very hard object inside. You pull out one of the hard objects, crack it open, and find a seed inside. To get a good cross-section of this soft fruit with hard objects inside, you freeze it and then slice it on a power saw. When you look at the cross section, you see a central area that is solid and fibrous and the sections of the fruit radiate out from this in all directions. Each section of the fruit appears to consist of two soft layers surrounding the hard object. A native tells you that this tree had clusters of beautiful yellow flowers just a few months ago. Classify the fruit you have found using the three classification schemes used in lab. 5 points

Origin:
simple       aggregate       multiple

Composition:
True       Accessory

Description: (fleshy, dry, etc. be specific)
fleshy drupe

16 points.
The gymno- part of gymnosperm meansnaked
What structure in a pine is specifically "gymno-"?ovule
The -sperm part of gymnosperm refers to seed
Which gymnosperm sporophyte most closely resembles the ferns?Cycadophyta
In many gymnosperms, the male and female
structures are on separate plants. This condition is known as
dioecious
What structure of the female Ginkgo tree makes it stink?integument of ovule
What type of shoot has leaves held singly in Ginkgo?long       short
What is the name for the endosporic microgametophyte in pine?pollen
What tissue must be penetrated to deliver sperm in pines?nucellus
What process takes place in the first spring of an ovulate pine cone?pollination
What process takes place in the second spring of an ovulate pine cone?syngamy
What process takes place in the third spring of an ovulate pine cone?seed dispersal
Which type of pine cone is simple?microsporangiate       megasporangiate
What structure makes a pine cone compound?bract
What structure distinguishes the Gnetophytes from the lower gymnosperms?vessels
The stamen of a flower is equivalent to a pine microsporophyll


Heterosporous Life Cycle Diagram. Turn this page sideways and arrange the 20 labels provided to you on this page to demonstrate your understanding of the heterosporous life cycle in angiosperms. Note: you should know that the labels cannot be repositioned! Once stuck down, you are stuck with their position! So plan carefully! 20 points.

anther
central cell
egg
embryo sac
endosperm
megagametophyte
megasporangium
megaspore
megasporocyte
meiosis
microgametophyte
microsporangium
microspore
microsporocyte
nucellus
pollen grain
sperm
sporophyte
syngamy
zygote


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