2. • Is a seed alive? Is a fruit alive? Answer
as completely as you can on your own
paper. (Hang on to your paper until the
end of class.)
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3. Asexual Reproduction
• Asexual reproduction is natural
“cloning.” Parts of the plant, such as
leaves or stems, produce roots and
become an independent plant.
• List some benefits and some drawbacks
to asexual reproduction.
4. Sexual Reproduction
• Sexual reproduction requires fusion of
male cells in the pollen grain with
female cells in the ovule.
• List some advantages and drawbacks to
sexual reproduction.
5. Terms to know:
• Haploid: having a single set of
chromosomes in each cell.
• Diploid: having two sets of
chromosomes in each cell.
• Mitosis: cell division, which produces
two genetically identical cells.
• Meiosis: reduction division, which
produces four haploid reproductive
cells.
7. Animals vs. Plants
Plant Reproduction Animal Reproduction
Life cycle
Alternation of
generations
No alternation of
generations
Gametes Haploid gametes Haploid gametes
Spores Haploid spores No spores
Gametes made
by
Haploid gametophyte,
by mitosis
Diploid organism, by
meiosis
Spores made
by
Diploid sporophyte, by
meiosis
No spores
8. Alternation of Generations
• Plants have a double life cycle with two
distinct forms:
• Sporophyte: diploid, produce haploid
spores by meiosis.
• Gametophyte: haploid, produce
gametes by mitosis.
9. Non-flowering plants
• Mosses, ferns, and related plants have
motile, swimming sperm.
• What kind of environmental conditions
would be required for reproduction in
these plants?
• What kinds of limits does external
reproduction impose on these plants?
12. Conifers
• Conifers (also non-flowering plants)
have reduced gametophytes.
• Male gametophyte is contained in a
dry pollen grain.
• Female gametophyte is a few cells
inside of the structures that become
the seed.
14. Conifer pollination
• Conifers are wind-pollinated plants.
• Chance allows some pollen to land on
the scales of female cones.
• Pollen germinates, grows a pollen tube
into the egg to allow sperm to fertilize
the egg.
• What are some advantages and
disadvantages to wind pollination?
15. Pollen go-betweens
• Showy flowers are the result of selection
for more efficient pollination strategies.
• Flower parts are modified leaves. Those
that were brightly colored attracted
insects in search of pollen.
• Why would insects search for pollen?
What other rewards do flowers offer?
• What are advantages and disadvantages
to relying on insects as pollinators?
18. Incomplete flowers
• Flowers are complete if they have all
parts, and perfect if they have both male
and female parts.
• Grass flowers: incomplete, usually
imperfect (separate male and female
flowers)
• A tulip is complete (though the sepals
are the same color as the petals) and
perfect.
28. • Use what you have learned about plant
life cycles to explain why most mosses
and ferns live in moist environments, but
flowering plants can live just about
anywhere.
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Editor's Notes
Fast, no mate required.
Beneficial for plants that must compete for scarce resources.
However, all individuals are genetically identical.
Fusion of egg and sperm cells.
May be limited to a certain season.
Slower than asexual reproduction.
Allows genetic mixing, increasing variability in a population.
Reproduction in these plants requires wet conditions, and requires having male and female parts close together.
Living conditions, plant size, and genetic mixing is limited.
Pollen itself is a protein-rich food for insects. Some plants offer other rewards, such as nectar.
