Plants evolved from green algae in the water to eventually move onto land. They developed vascular tissue to transport water and nutrients, a waxy cuticle to prevent drying out, and specialized reproductive structures like spores and seeds that do not require water. Plants are classified based on these adaptations, with those lacking vascular tissue called bryophytes, those with vascular tissue divided into seedless vascular plants like ferns and seed-bearing vascular plants. Seed-bearing plants are further divided into gymnosperms with exposed seeds and angiosperms with enclosed seeds within fruits.

1. Plant Diversity
The Evolution and
Classification of
Plants
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2. Slide # 3
PLANT CHARACTERISTICS
• Multicellular eukaryotes
• Photosynthetic autotrophs containing
chloroplasts.
• Non-mobile (fixed to one spot)
• Cell walls made of cellulose
• Responds to environment and grows
through the use of hormones

3. Slide # 4
Plants Make the The Move to Land
The ancestors of plants were multicellular green algae. They
were completely immersed in water & dissolved minerals.
To move onto land, plants had to solve these problems:
 How to get chemical resources (water, minerals,
oxygen, and carbon dioxide) separated into air and
soil
 How to transport resources within the plant.
 How to prevent from drying out
 How to reproduce without water

4. Slide # 5
Some Adaptations (solutions)-
 Have body parts extending into both air and
soil
 Develop a vascular system to transport
resources in plant
 Have a protective layer – cuticle (waxy outer
layer) to keep from drying out
 Specialized structures for reproduction
including spores & seeds that do not dry out

5. Slide # 6
Plants are classified based on
whether or not they have
1. Vascular System (transport)
2. Seeds
3. Flowers (enclosed seeds)

6. Slide # 7
Concept Map: Plants are divided 1st by
whether or not they have a vascular system.
Plants
Has NO Vascular Has Vascular
Tissue Tissue
Bryophytes Tracheophytes

7. Slide # 8
Bryophytes
-NONVASCULAR
 Most primitive plants
 Found in moist, shady areas
 NO vascular (transport) system
 Small size due to no vascular tissue
 No true roots, stems, or leaves
 Needs water for reproduction.
 Reproduces using spores, -a water-proof
single cell that can grow into a new organism.
 Most common example: Mosses

8. Slide # 9
Typical Moss Plant
(most common bryophyte)
Spores form inside the
capsule.
Notice the problem of nutrient
separation into air and soil is
solved with underground and
above ground parts.
(Although NO TRUE roots,
stems or leaves are present)

9. Slide # 10 Tracheophytes
-Vascular Plants-
• Contains two types of specialized vascular
tissues for transport within the plant:
– Xylem- transports H20 up from roots.
– Phloem- transports food made during
photosynthesis and nutrients to where they are
needed in the plant.
• Presence of a vascular system allowed plants to
become tall.
• Has specialized organs: roots, stems, and leaves.

10. Slide # 11
Tracheophytes are divided into two groups by
whether or not they reproduce with seeds.
Tracheophytes
Seedless Seeded
Ferns use
spores

11. Slide # 12
The Fern - a seedless
vascular plant
There
o Contain a vascular are
system. Sori 11,000
species
o They grow in moist, of ferns.
shady habitats.
o Has underground
stems, roots, & large
leaves called fronds.
o Reproduce using
spores, Not seeds.

12. Slide # 13
Seed-Bearing Tracheophytes
ADVANTAGE: Developed reproductive
strategies that do not need water:
2. Seed contains
• A fully developed embryo
• Food supply for embryo
• A water-proof seed coat to keep from drying out
• Sperm transferred in water-proof pollen
through pollination by wind or animals.
• Developed seed-bearing structures: Cones
and Flowers

13. The two Seeded Tracheophyte groups are
divided by whether or not they have
enclosed seeds -protected inside a fruit or if
seeds are exposed to the environment.
Tracheophytes
Seedless Seeded
Ferns use Gymnosperms Angiosperms
spores
“naked” or Flowers produce
exposed fruit w/ enclosed
seeds seeds

14. Gymnosperms- “naked
Slide # 15
• Cycad (Sago palm), seed”
• Ginkgo,
• Conifer (pine, spruce, firs, cedars, sequoias,
redwoods, junipers, yews, & cypress trees)
Sago Palm Ginkgo Ginkgo

15. Slide # 16
Sequoia
Gymnosperms-Conifers
• Most common gymnosperms are
Conifers
• Conifers have leaves called
needles or scales have a reduced
surface area and thick waxy coat
on the needle to reduce water loss
and prevents freezing.
Juniper
Pine

16. Slide # 17
Conifer
•
Reproduction
Male cones produce Pollen
pollen and the female
cone produces eggs and
seeds.
• Pollen is inefficiently
transferred by the wind.
• Once mature, the scales
on the female cone dry Seed
out and open scattering Cone
the seeds by the wind.
Pollen
Cone

17. Slide # 18
Angiosperms- “enclosed seeds”
• These are flowering plants the
encourage direct and efficient pollen
transfer (smell, color and offering nectar)
• Pollinators are flying insects, birds, and
bats that transfer pollen from flower to
flower.
• Flowers contain ovaries, which is where
eggs/seeds are produced.
• A fruit is the pollinated ovary containing
mature seeds.

18. Slide # 19
Fruit can aid in dispersal of seed to
reduce competition with parent plant.
• Winged fruit – glides to
new location (maple fruit)
• Floating fruit – can float to
new locations (coconut)
• Fleshy fruit - sweet bright
colored fruit have seeds
that survive the digestive Maple seeds: Winged fruit
system of animals that eat
the fruit (apple)
• Spiny fruit- Velcro like
projections attach to the fur
of animals (cockleburs)
Burdock: Spiny fruit