Transcript Plant Divisions

Plant Diversity
The Evolution and
Classification of Plants
Why should we care about plants, at all?
Carbon dioxide levels
Indicators for ground level
pollution, long before animals
Japan/ radioactive food….
But…
Kudzu- invasive
Did you know……
Oak trees do not reach sexual maturity with
acorns until they are fifty years old or older
And that you are 16 times more likely to be
struck by lightning if you’re standing under
an oak tree than any other type of tree
Did you know….
Bamboo can grow up to three feet in a 24 hour
period.
Did you know…
The squirting cucumber (Ecballium
elaterium), when brushed by a passerby,
ejects its seeds and a stream of poisonous
juice that stings the skin
Did you know…
Fruits have become more expensive because
we have killed more bees (and birds) with
insecticides….
What do I know about plants?
True or False
1. All plants perform photosynthesis.
2. All plants need water and nutrients.
3. All plants reproduce using flowers.
4. All plants reproduce using seeds.
5. Plants eat soil
6. Some plants lose their leaves in the
winter because it gets too cold
7. Plants know their up from their down
8. Plants have hormones the same way we
do
9. Leaves are different on the two sides
Random thought questions….
• Are there girl and boy plants?
• Why are mosses so short, and why do
they live only in moist areas?
• When you eat an apple, what are you
really eating?
• If this whole ‘we came from bacteria
thing’ is true, where do scientists
think plants came from?
Precursors to plants…algae?
PLANT CHARACTERISTICS:
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Multicellular,eukaryotic, autotrophic
Can’t move
Photosynthesize and have chlorophyll
Cell Walls made of cellulose
Plants Make 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:
1.
How to get chemical resources (water, minerals, oxygen, and carbon
dioxide) separated into air and soil
2. How to transport resources within the plant.
3. How to prevent from drying out
4. How to reproduce without water
Some Adaptations (solutions)1. Have a protective layer – cuticle (waxy
outer layer) to keep from drying out
Some Adaptations (solutions)2. Have body parts extending into both air and soil
(roots)
3. Have leaves – photosynthesis takes place on tops of
leaves
Some Adaptations (solutions)4. Develop a vascular system to transport
resources in plant
5. . Specialized structures for reproduction
including spores & sex cells (seeds) that do not
dry out
Plant Growth:
In response to seasons …
Evergreen
Deciduous
Plant Growth:
In response to stimuli …
Gravitropism
Phototropism
They grow towards light, which is usually away
from where gravity is trying to pull them …
Plants are classified based on
whether or not they have
1. Vascular System ( pipes for
transport)
2. Seeds
3. Flowers (enclosed seeds)
Nonvascular Plants
1. Most primitive plants
2. NO “pipes” (vascular system)
3. Small size due to no vascular tissue
4. No true roots, stems, or leaves
5. Most common example: Mosses, liverworts
Nonvascular Plants
6. Need WATER to
reproduce
7. Reproduction can be
sexual or asexual
8. Tend to be located near
water or in moist/shady
places.
Typical Moss Plant
(most common bryophyte)
NO TRUE roots, stems
Tracheophytes (Ferns)
-Vascular Plants-
Contains vascular tissues.. But not much
else!
The Fern - a seedless vascular
plant
1. Contain a vascular
system – can grow
taller than
mosses
2. They grow in
moist, shady
habitats.WHY?????
There are
11,000 species
of ferns.
Vascular-seedless
3. Has underground
stems, roots, &
large leaves called
fronds.
4. Reproduction can be
sexual or asexual
5. Example: Ferns,
horsetails, club
mosses
Gymnosperms- “naked seed”
• Cycad (Sago palm),
• Ginkgo,
• Conifer (pine, spruce, firs, cedars,
sequoias, redwoods, junipers, yews, &
cypress trees)
Sago Palm
Ginkgo
Ginkgo
Gymnosperms
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Have pipes and seeds, but no flowers
Reproduction relies on wind and water
Use cones and pollen
Example: Pine trees
Gymnosperms-Conifers
1. Most common gymnosperms are
Conifers
2. 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.
Pine
Juniper
Sequoia
How do gymnosperms spread
their seeds?
Conifer
Reproduction
1. Male cones produce
pollen and the female
cone produces eggs and
seeds.
2. Pollen is inefficiently
transferred by the wind.
3. Once mature, the scales
on the female cone dry
out and open scattering
the seeds by the wind.
Pollen
Cone
Pollen
Seed
Cone
Angiosperms- “enclosed
seeds”
Angiosperms- “enclosed
seeds”
1.
These are flowering plants the encourage
direct and efficient pollen transfer
(smell, color and offering nectar)
2. Pollinators are flying insects, birds, and
bats that transfer pollen from flower to
flower.
3. Flowers contain ovaries, which is where
eggs/seeds are produced.
4. A fruit is the pollinated ovary containing
mature seeds.
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Angiosperms- “enclosed
seeds”
Has pipes, seeds, and flowers
Reproduction with flowers:
Male Parts: stamen (anther and filament)
Female Parts: Pistil (stigma, style, overy)
Fruit can aid in dispersal of seed to
reduce competition with parent plant.
1.
2.
3.
4.
Winged fruit
Floating fruit
Fleshy fruit
Spiny fruit
Maple seeds: Winged fruit
Burdock: Spiny fruit
Review of Plant Evolution:
Quiz Time
• What did plants have to overcome to live on land?
• What is the most primitive division of plants
because they have no vascular system?
• What is the most common example in this division
and how do they reproduce?
• Why are mosses so small?
• What is the division of plants that contain a
vascular system?
• What did a vascular system do for plants sizewise?
• How are mosses and ferns different?
• How are mosses and ferns alike?
Quiz Time
• How are Tracheophytes different from
bryophytes?
• How are tracheophytes divided?
• What are the advantages of seeds over
spores?
• What other advantages did seed-bearing
plants have over spore-bearing plants?
• What are the two divisions of the seedbearing tracheophytes?
Quiz Time
• What does the term Gymnosperm mean?
• What are the most common of the
Gymnosperms?
• What is the evolutionary importance of needles?
• What structures do conifers use to reproduce?
• Were are seeds located in the cone?
• Even though wind-dispersal of pollen is
inefficient, what did it allow plants to overcome?