Objective Objective Students will be able to Students will be able to
Describe the characteristics of Describe the characteristics of plantsplants
An Overview of Plants
Plants Between 260,000 and 300,000 different
species Have adapted to almost every
environment
An Overview of Plants
Plants have some general characteristics: Roots or root-like structures Can perform photosynthesis Has cells that are different from those
of other organisms
An Overview of Plants
Plant cells Cell walls, which provide structure and
protection.
Green pigment chlorophyll Central vacuole, which regulates water
content.
An Overview of Plants
Earliest plants were probably green algae, dating back to 420 m.y.a.
Cone-bearing plants show up around 300 m.y.a.
Flowerings plants came into existence around 120 m.y.a.
An Overview of Plants
Scientists think plants probably evolved from green algae in the sea because:Plants and green algae have the same
types of chlorophyll and carotenoids.Fossils of early plants are similar to the
ancient green algae.
An Overview of Plants
When plants moved to land, they had to adapt to new conditions.
More sunlight and carbon dioxide were available.
Plants developed a cuticle—a waxy, protective layer secreted onto the surface of the plant which holds water in and allows plants to live in drier conditions.
An Overview of Plants
When plants moved to land, they had to adapt to new conditions.
Cell walls developed cellulose, a chemical compound that provides structure and support, which allows plants to stand upright on land.
Water-resistant spores and seeds enabled plants to reproduce on land.
An Overview of Plants
Plant classification
Vascular plants use tube-like structures that carry water and nutrients throughout the plant.
Nonvascular plants lack tube-like structures and use other ways to move water and nutrients.
ObjectiveObjective Students will be able to:Students will be able to:
Identify seedless plants Identify seedless plants Distinguish between vascular and Distinguish between vascular and
nonvascular seedless plantsnonvascular seedless plants Explain a pioneer speciesExplain a pioneer species Explain how humans use seedless Explain how humans use seedless
plantsplants
Seedless Plants
Nonvascular plants Very small plants that have rhizoids
rather than roots Seedless Vascular plants
Reproduce by spores, but have vascular tissue that carries water and nutrients throughout the plant
Nonvascular plants Water is absorbed and distributed
directly through cell membranes and cell walls.
Grow in damp environments Reproduce by spores rather than
seeds
Examples of nonvascular plants: Mosses - green,
leaflike growths arranged around a central stalk
Nonvascular plants
Nonvascular plants Examples of
nonvascular plants: Hornworts - have
only one chloroplast in each of their cells
Nonvascular plants Pioneer species
Organisms that are the first to grow in new or disturbed areas and which change environmental conditions
Seedless Vascular plants
Reproduce by spores, but have vascular tissue that carries water and nutrients throughout the plant
Can grow bigger and thicker than nonvascular plants
Seedless Vascular plants Examples of seedless vascular
plants Ferns - largest group of
seedless vascular plantsHave stems, leaves, and rootsLeaves are called frondsReproduce by spores found on
the back of their fronds
Seedless Vascular plants Examples of seedless vascular
plants Horsetails - jointed stem with a
hollow center
Seedless plants Seedless plants are important because
they have many useful purposes Fuel—decaying seedless plants are
compressed into peat and eventually coal
Soil conditioners Ferns can be used for weaving material
and basketry.
ObjectiveObjective Students will be able to:Students will be able to:
Describe the characteristics of a seed plantDescribe the characteristics of a seed plant Describe the anatomy of a seed plantDescribe the anatomy of a seed plant Distinguish between gymnosperms and Distinguish between gymnosperms and
angiospermsangiosperms Compare and contrast monocots and dicotsCompare and contrast monocots and dicots Explain how humans use seed plantsExplain how humans use seed plants
Seed Plants
Have leaves, stems, roots, and vascular tissue
Reproduce by seeds, which contain an embryo and stored food
Seed Plants Leaves
Epidermis - a thin layer of cells on the upper and lower surfaces of a leaf
May have a waxy cuticle coating the epidermis Stomata—small openings in the epidermis that
allow carbon dioxide, water, and oxygen to enter and exit a leaf
Each stoma is surrounded by two guard cells that open and close it.
Seed Plants
Leaves Palisade layer -
contains chloroplasts, where most food is made
Spongy layer - loosely arranged cells and air
Seed Plants Stems
allow the movement of materials between leaves and roots.
Usually above ground Support the branches, leaves, and
flowers May store food
Seed Plants Roots
Roots collect water and nutrients from the ground.
Roots anchor plants so they don’t blow away.
May store food or water.
Seed Plants Vascular tissue
Xylem tissue—transports water from the roots throughout the plant
Phloem tissue—moves food from where it is made to other parts of the plant
Cambium tissue—produces new xylem and phloem cells
Seed PlantsSeed Plants There are two kinds of seed plantsThere are two kinds of seed plants
GymnospermsGymnosperms AngiospermsAngiosperms
GymnospermsGymnosperms Vascular plants that produce
seeds that are not protected by fruit Oldest trees alive Gymnosperms have no flowers. Leaves are often needlelike or scalelike
GymnospermsGymnosperms ConifersConifers
Cone-bearing, reproducing because of Cone-bearing, reproducing because of male and female conesmale and female cones
Woody Woody Most are trees, some are shrubsMost are trees, some are shrubs First trees on earthFirst trees on earth
GymnospermsGymnosperms
Conifers are the oldest living things on earth
Left: oldest tree is a Left: oldest tree is a bristle-cone pine, the bristle-cone pine, the Methuselah tree is 4,839 Methuselah tree is 4,839 years old years old
Right: Newly Right: Newly discovered in Sweden, discovered in Sweden, this spruce has a root this spruce has a root system that is 9,600 system that is 9,600 years old. years old.
GymnospermsGymnosperms
Conifers are the oldest living things on earth
NOVA Online | MethusNOVA Online | Methuselah Treeelah Tree
GymnospermsGymnosperms
Conifers are the tallest living things on earth
Hyperion is the newly Hyperion is the newly discovered sequoia that is discovered sequoia that is 379.1 feet tall, beating out 379.1 feet tall, beating out the Stratospheric Giant at the Stratospheric Giant at 370.5 feet.370.5 feet.
GymnospermsGymnosperms
Conifers are the widest living things on earth
Left: the General Left: the General Sherman Redwood at Sherman Redwood at 102 ft. around 102 ft. around
Right: The Tree at Right: The Tree at Santa Maria del Tule, Santa Maria del Tule, a Montezuma Cypress a Montezuma Cypress at 164 ft. in at 164 ft. in circumference circumference
GymnospermsGymnosperms
Conifers are the widest living things on earth
This is known as the This is known as the “Tree of a hundred “Tree of a hundred horses.”horses.”
At 204 ft around it At 204 ft around it was the widest tree was the widest tree ever measuredever measured
It now grows in three It now grows in three piecespieces
AngiospermsAngiosperms
Vascular plants that flower and have fruit that contains seeds Fruit develops from flowers. Most fruit contains seeds.
AngiospermsAngiosperms
Two groups:
MonocotsOne cotyledon in seedVascular bundles scatteresFlower parts in multiples of threeParallel veins on leaves
AngiospermsAngiosperms
Two groups:
DicotsTwo cotyledons inside their seeds Vascular bundles in ringsVascular bundles in rings Flower parts in multiples of four or fiveFlower parts in multiples of four or five Branching veinsBranching veins
AngiospermsAngiosperms Different angiosperms have different
life cycles: Annual - the plant’s life cycle is completed
within one year Biennial - the plant’s life cycle is completed
in two years Perennial - takes more than two years to
grow to maturity