Transcript 8th Hour PowerPoint

Chapter 25
Plants
Brandon Kraft,
Carly Miller,
and Nick Rego
Evolutionary Trends
Among Plants


Photoautotrophs-organisms
that get energy from sun
and CO2

Non-vascular plants

Account for remainder
of plants

Bryophytes
Vascular plants

Account for most plants

Roots, stems, leaves

Liverworts

Three Types

Hornworts

Mosses

Seedless Vascular Plants


Cycads, lycophytes, ferns
Seed-Bearing Vascular
Plants

Gymnosperms

Angiosperms
Evolution of Roots,
Stems, and Leaves


Roots


Evolved for life on land

Underground, absorbtive
Shoot systems

Stems and leaves

Above Ground


Absorb Sunlight and
CO2
Support of cell wall

Evolved Lignin

Vascular tissue- for
transport of materials

Xylem

Phloem
Water conservationnecessary because of air
exposure (prevents
dehydration

Cuticle

Stomata
Evolution of Pollen and Seeds

Heterospory



Produce two types of spores

Sperm-bearing gametophytes

Female gametophytes
Spread by air, insects, birds
Seeds - contain embryo and sustinence
Bryophytes

Mosses(most common), liverworts, hornworts (nonvascular)

3 adaptive features:
1. Above ground parts display a cuticle with numerous stomata
2. Cellular protective jacket surrounds the sperm-producing and
egg-producing parts of the plant to prevent drying
3. The embryo sporophyte begins life inside the female
gametophyte

Branched, feathery patterns

Reproduce w/ flagellated sperm, which require liquid water to
reach and fertilize the eggs
Moss Life Cycle
Existing Seedless
Vascular Plants

Whisk ferns, Lycophytes, Horsetails, Ferns

3 Differences from Bryophytes
 Sporophyte not attached to a gametophyte
 Has vascular tissues
 Longer phase in life cycle

Habitat
 Moist places
Gametophytes lack vascular tissue


Sperm needs water to reach egg
Life Cycle of a Fern
The Rise of the
Seed-Bearing Plants
*360 million years ago

3 differences from seedless vascular plants

1. Produce pollen grains-the sperm-bearing male gametophytes

Microspores give rise to pollen grains

Does not depend on H20

2. Also produce megaspores, which develop inside ovules-at
maturity is a seed (consist of female gametophyte)

3. Have H20 conserving traits

Thicker cuticles

Stomata recessed below the leaf surface.
Spore of A Lycophyte
Seed-Bearing Plants

Depend on

Pollen grains

Ovules that mature
into seeds

Tissue changes
adapted to dry
conditions
GymnospermsPlants with “Naked” Seeds

Have exposed seeds
gymnos means “naked,” sperma means “seed”
Conifers - have cones
 Woody trees/shrubs with needlelike leaves
 Cones- clusters of modified leaves that surround the spore-producing
structures
 Firs, yews, spruces, junipers, larches, cypresses, etc.
Lesser Known Gymnosperms

Cycads-have pollen-bearing and
seed bearing cones that form on
separate plants
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Tropical/Subtropical areas
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Largest seed-bearing cones
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Many vulnerable to
extinction
Gingko
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Gingko biloba - only
survivor
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Diverse in dinosaur times

Males are resistant to
insects, disease, and air
pollutants

Gnetophytes-woody plants that
have 3 types

Tropics and arid areas
**Groups of existing
gymnosperms include conifers,
cycads, ginkgos, and
gnetophytes, which bear their
seeds on exposed surfaces of
cones and other sporeproducing structures.
Conifers


Gymnosperms that
reproduce via Cone
Structures (Pinecones)
Conifers produce both male
and female pinecones

Male Pinecones


Produce Microspores (Pollen
grains) that drift into the air
Female Pinecones

Produce Megaspores
(Female Gametophtes)
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Accept Pollen grains
Pollen Grows into Ovule
Fertilization Occurs
months after pollination
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Slow Reproductive Rate

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Disadvantage
Angiosperms reproduce
faster and compete for
resources
Deforestation

Vulnerable
Angiosperms
The Flowering Seed-Bearing Plants
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Most Successful Plants
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Only plants that flower

Angeion- Female
reproductive part of
flower

Requires pollination


Transfer of pollen from
one plant to next
Pollination Processes

Airborne pollen

Pollinators

Insects, bats, birds

Coevolution
Angiosperm diagram:
Dicots and Monocots

Two Types

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Monocots and Dicots
Monocots
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Monocotyledon
One cotyledon (seed leaf for storage of food) in seeds
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Floral parts in groups of threes
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Parallel veins in leaves
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Orchids, palms, lilies, grasses (most crops-wheat, corn, etc)
Dicots
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Dicotyledon
Two cotyledons in seeds
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Floral parts in groups of four or five
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Net-veined leaves
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Most Herbaceous (non-wooden) plants
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Most flowering shrubs and trees
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Water Lilies, Cacti