Notes – Chapter 21-22 – Plants – Kingdom Plantae
Plant Adaptation to Life on Land
• Plants need water and minerals
• Usually get water and minerals from soil
• Most fruits, leaves, and stems are covered with a protective, waxy layer
called the cuticle.
• Leaves are the area in which photosynthesis usually occurs
The lives of plants include two stages, or alternating of generations as a
gametophyte (haploid) and a sporophyte (diploid)
**In their haploid phase (gametophyte stage) haploid organisms produce haploid
spores (a unit of sexual reproduction) that undergo mitosis. These spores can fuse
with each other or with another plant’s spore (sexual reproduction) to create a
zygote.
**The fertilized zygote from the gametophyte generation develops into a
sporophyte, which has diploid cells. The cells of the sporophyte undergo meiosis
to create haploid cells which develop into gametophytes, thereby starting a new
phase in the alternation of generations and bringing the organism completely
through the alternation of generations, from gametophyte to sporophyte and
back again. (See below)
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Vascular plants vs. non-vascular
Non-Vascular
 Have NO true roots or stems; unlike trees, they lack water conducting
tissues (xylem and phloem)
 Can reproduce asexually when their spores fuse but usually reproduce
sexually
 In sexual reproduction they have to have a film of water (male sperm have
to swim to female egg)
 Fertilized egg, the zygote, undergoes mitosis and is diploid, a sporophyte;
becomes a stalk attached to the haploid gametophyte
 They are very small and includes , moss, liverworts and hornworts (see
PowerPoint)
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Vascular Plants
Have tissue that will conduct water from roots to leaves
o Xylem tissue conducts water and minerals (See PowerPoint)
o Phloem tissue transfers carbohydrates like sugars for the plants food
(See PowerPoint)
Includes plants that produce seeds and those that do not
Non-seed plants like ferns, club mosses, horsetails
Seed plants – seeds contain an embryo, seed coat and food supply
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o Gymnosperms that produce “naked seeds” on cones not covered in
a fruit; trees called conifers like pine trees
o Angiosperms are all plants and trees that produce flowers and have
covered seeds protected inside of a fruit
 Sexual Reproduction  the zygote will undergo mitosis and becomes an
embryo in a seed that germinates (sprouts) and eventually becomes a
seedling plant
Monocotyledons (monocots) vs. Dicotyledon (dicots)
Dicots
 A major group of flowering plants (angiosperms)
 The plant embryo has 2 cotelydons (Looks like a pinto bean cut in two
pieces) that supply food to the embryo
 Maple trees, oak trees, most flowers, beans, magnolia trees, beech trees
willows just to name a few!
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Monocots
 Flowering plants
 One cotyledon surrounds the embryo
 Endosperm provides food for the embryo
 Corn, grasses, lilies, rice, wheat, orchids
Germination of a Seed
The skin splits and
the shoot
First the young root
straightens, pulling
appears.
the cotyledons with
it.
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The main root gets
bigger and grows side
roots, and the first
leaves appear.
Co-evolution of two species alongside each other
 an extreme example of mutualism
 Evolutionary influence between two species (the evolution of two species
totally dependent on each other).
 Each of the species exerted selective pressure on the other, so they evolve
together.
 Plants and pollinators is an example.
o The plant and the pollinator benefit each other.
o The plant expends less energy on pollen production and instead
produces elaborate flowers, nectar, and/or odors.
o An organism like a honeybee is attracted to the nectar and then
becomes dependent on a flower’s nectar and the flower will then
become dependent on the pollinator for pollination
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