Page 1 Exam IV 1996 127 - ____ = ____/____ = _____.___
Spring 1996
Biology of Plants

Exam IV


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 forms contained in layers of coverage. Trace the continued evolution through Selaginella, Gymnosperms and Angiosperms. Don't write a book for each, but tell about the main innovation regarding coverage of the female phases in each group of organisms.




endosporangial, integument



wrapped by carpel
sometimes embedded in receptacle


This last section of evolution has also shown great changes in the megagametophyte. Describe the megagametophyte of each of these three life histories. You do not need to mention the coverage of the gametophyte, just the gametophyte itself. For a moss, one might write: thallus, rhizoid, "stem", "leaf", archegonium, egg.

thallus, rhizoid, archegonium, egg



thallus, archegonium, egg



antipodals, central cell, synergids, egg


I'm sure you will not be surprised that the next question is to describe the microgametophyte of these three organisms to show the direction of evolution in this important structure. Here please also write some words about numbers and kinds of gamete(s) produced.

endosporic, antheridium, many sperm, motile sperm



spore wall, prothallial cells, tube cell, generative cell, two sperm, +/- motile sperm



spore wall, tube cell, generative cell, two sperm, non-motile sperm


Pollination botany deals with innovations that plants have evolved to achieve pollination. Describe the important features of flowers that make it possible for them to be pollinated by bees or wasps.

The equivalent of a stamen in a pine cone ismicrosporangiate cone scale
The equivalent of a carpel in a pine cone ismegasporophyll
The equivalent of a petal in a pine cone isbract
The equivalent of a locule in a pine cone isnone

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

In the following table, compare the structure and organization of primitive and advanced flowers.
Primitive FlowerAdvanced Flower
radial bilateral
many parts fewer parts
elongate axis short axis
bisexual unisexual
beetle pollinated bee, wind pollinated
hypogynous epigynous
superior ovary inferior ovary
large flowers tiny flowers
single flowers gathered into head
all flowers same division of labor

Diagram an angiosperm pollen grain (microgametophyte) and an embryo sac (megagametophyte) and label them completely.
pollen wall
tube cell
generative cell
central cell

What would you add to the angiosperm pollen grain to make it a pine pollen grain?1.spore wall sacs
2.prothallial cells

Describe what is unusual about syngamy in angiosperms?
it is double

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

What three things constitute a seed?1.seed coat
2.embryo tissue

There are three distinct ways to classify a fruit. Tell the main features of each of them.
1. Origin:simple - one flower one fruit
aggregate - one flower many fruits fused together
multiple - many flowers many fruits fused together
2. Composition:true - ovary wall only
accessory - includes receptacle, etc.
3. Description:fleshy - juicy wall when mature
dry - papery or hard wall when mature

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