Transcript Plants- Part One

Kingdom Plantae
22.1 Intro to Plants
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What is a plant? A member of the kingdom
Plantae. Plants are multi-cellular eukaryotes
with cell walls composed of cellulose
Plants are autotrophs, they make their own
food by photosynthesis using pigments such as
chlorophyll a & b.
Plant Reproduction
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Plants have life cycles that are characterized
by alternation of generations
During the life cycle, plants alternate from a
haploid gametophyte and a diploid sporophyte.
These forms vary greatly from phylum to
phylum
In order to gain independence from water,
plants had to evolve to reproduce without it
What Plants Need to Survive
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Sunlight- plants use the energy from the sunlight to
produce food by photosynthesis
Water and Minerals- plants need a constant supply of
water in order to make food. Minerals are nutrients
in the soil that are needed for plant growth
Gas exchange- plants need CO2 for photosynthesis
and O2 for respiration
Movement of water and minerals- plants must be able
to take in both water and minerals and transport them
throughout.
Evolution of Plants
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Plants once lived only in the water. All life processes
took place there, including reproduction
As plants evolved, they developed ways to reproduce
and live on land
Sperm no longer swam in water for reproduction and
plants developed ways to take in and store water
The most well known ancestor of plants is green
algae
Bryophytes- Non Vascular Plants
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Mosses, liverworts and hornworts are all
bryophytes
Bryophytes need water to reproduce and are
very small because they lack tissue to transport
water and nutrients
Bryophytes do not have true roots, stems and
leaves. They have root like structures called
rhizoids to anchor them in the ground
Examples
Moss
liverwort
Hornwort
Seedless Vascular Plants
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Vascular tissue allows plants to transport water
and nutrients throughout their body
Tracheids are specialized cells that make up
xylem, the tissue that transports water
Phloem is tissue that transports food, meaning
nutrients and carbohydrates
Xylem and phloem can transport water and
food even against gravity
Ferns and Their Relatives
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Ferns are members of the phylum Pterophyta
and have true vascular tissue. They also have
strong creeping roots called rhizomes and large
leaves called fronds
Horsetails and Club mosses are also seedless
vascular plants
Examples
horsetail
Fern
Club Moss
Seed Plants
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Adaptations that allow seed plants to repro
duce outside of water include flowers, cones,
pollination and protection of embryos in seeds
Gymnosperms and Angiosperms are examples
of seed plants
Gymnosperms- Cone Bearers
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Include gnetophytes, cycads, ginkgoes, conifers
Conifers are considered “evergreens” they retain their
needle shaped leaves all year
All gymnosperms reproduce using exposed seed, the
name literally means “naked seed”
The most common gymnosperm is the conifer,
phylum Coniferophyta. These include pines, spruces,
firs, cedars
Angiosperms- Flowering plants
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Have unique reproductive structures called
flowers
Flowers contain ovaries, which protect and
surround the seed
Fruits develop after fertilization, (pollination)
and protect the seed and aid in dispersal
Diversity of Angiosperms- the two
classes
MONOCOTS
Embryo with single cotyledon
DICOTS
Embryo with two cotyledons
Pollen with single furrow or pore Pollen with three furrows or pores
Flower parts in multiples of
three
Flower parts in multiples of four or
five
Major leaf veins parallel
Major leaf veins reticulated
Stem vacular bundles scattered
Stem vascular bundles in a ring
Fibrous roots
Taproots
Secondary growth absent
Secondary growth often present