PlantsPlants

PlantsPlants

The plant world is a diverse world.The plant world is a diverse world. There are plants that trap animals, others There are plants that trap animals, others

that bloom every 30 years, and still others that bloom every 30 years, and still others that smell like rotting meat!!!that smell like rotting meat!!!

Although you probably donAlthough you probably don’’t see these t see these uncommon plants everyday, all plants, the uncommon plants everyday, all plants, the common and the bizarre, all share some common and the bizarre, all share some common traits.common traits.

What is a Plant?What is a Plant?

Members of the plant kingdom share many Members of the plant kingdom share many characteristics.characteristics.

All plants are autotrophs, or organisms All plants are autotrophs, or organisms that produce their own food. All plants that produce their own food. All plants are eukaryotes that contain many cells. are eukaryotes that contain many cells. In addition, all plant cells are In addition, all plant cells are surrounded by a cell wall.surrounded by a cell wall.

Adaptations for living on Adaptations for living on LandLand

Most plants live on the land. How is this any Most plants live on the land. How is this any different from living in the water?different from living in the water?

Think about this…Think about this… Multicellular green algae float around in the ocean. Multicellular green algae float around in the ocean.

They obtain water and other materials DIRECTLY They obtain water and other materials DIRECTLY from the water around them.from the water around them.

For plants to survive on land, they must have For plants to survive on land, they must have ways to obtain water and other nutrients ways to obtain water and other nutrients from their surroundings, retain water, from their surroundings, retain water, transport materials in their bodies, support transport materials in their bodies, support their bodies, and reproduce.their bodies, and reproduce.

Obtaining WaterObtaining Water

All organisms need water to survive All organisms need water to survive (DUH!)(DUH!)

Obtaining water is easy for something like Obtaining water is easy for something like algae, it just diffuses into the cell. Its algae, it just diffuses into the cell. Its trickier for plants though…trickier for plants though…

Because most plants live on land, they Because most plants live on land, they need adaptations for obtaining water from need adaptations for obtaining water from the soil. Plants also must have ways to the soil. Plants also must have ways to obtain nutrients from the soil.obtain nutrients from the soil.

Retaining WaterRetaining Water

After getting water, plants need a means of After getting water, plants need a means of holding onto it. If they werenholding onto it. If they weren’’t able to, they t able to, they could easily dry out due to evaporation.could easily dry out due to evaporation.

When there is more water in plant cells than the When there is more water in plant cells than the air around it, water leaves the plant and enters air around it, water leaves the plant and enters the air.the air.

One adaptation that helps the plant reduce One adaptation that helps the plant reduce water loss is the cuticle.water loss is the cuticle.

CuticleCuticle: Waxy, waterproof layer that covers the : Waxy, waterproof layer that covers the leaves of most plants.leaves of most plants.

Transporting MaterialsTransporting Materials

A plant needs to be able to transport food, A plant needs to be able to transport food, water, minerals, and other materials from water, minerals, and other materials from one part of its body to another.one part of its body to another.

In general, water and minerals are taken In general, water and minerals are taken up by the bottom part of the plant while up by the bottom part of the plant while food is made at the top. Even though this food is made at the top. Even though this is the case ALL plant cells need water, is the case ALL plant cells need water, food, and minerals.food, and minerals.

Transporting Materials (cont.)Transporting Materials (cont.)

In tiny plants, materials simply move from In tiny plants, materials simply move from one cell to the next.one cell to the next.

Larger plants need a better method of Larger plants need a better method of transport, so these plants have a tissue transport, so these plants have a tissue that transports material called vascular that transports material called vascular tissue.tissue.

Vascular TissueVascular Tissue: A system of tube-like : A system of tube-like structures inside a plant through which structures inside a plant through which water, minerals, and food move.water, minerals, and food move.

Transporting Materials (cont.)Transporting Materials (cont.)

Xylem: Xylem: Vascular tissue that helps Vascular tissue that helps transport water and nutrients up a transport water and nutrients up a vascular plant.vascular plant.

Phloem: Phloem: Vascular tissue that helps Vascular tissue that helps transport food down a vascular plant.transport food down a vascular plant.

Cambium: Cambium: Produces new xylem and Produces new xylem and phloem.phloem.

SupportSupport

A plant must be able to support its own A plant must be able to support its own body. Again, this is a simple task for small body. Again, this is a simple task for small plants as they have less body to hold up, plants as they have less body to hold up, but can be difficult for larger plants.but can be difficult for larger plants.

Large plantsLarge plants’’ food making parts need to be food making parts need to be exposed to as much sunlight as possible, exposed to as much sunlight as possible, so they have a series of rigid cell walls and so they have a series of rigid cell walls and vascular tissue to strengthen and support vascular tissue to strengthen and support their bodies.their bodies.

ReproductionReproduction

All plants undergo sexual reproduction that All plants undergo sexual reproduction that involves fertilization. involves fertilization.

For algae and some plants, this can only For algae and some plants, this can only happen in a water environment. This is happen in a water environment. This is because the sperm cells swim through the because the sperm cells swim through the water to reach the egg cells.water to reach the egg cells.

Other plants have adapted in a way that Other plants have adapted in a way that they can reproduce sexually on land.they can reproduce sexually on land.

ReproductionReproduction

Many plants have developed a specific Many plants have developed a specific adaptation to allow them to reproduce sexually adaptation to allow them to reproduce sexually on land.on land.

Pollen: Carries plant sperm cells that allow for Pollen: Carries plant sperm cells that allow for sexual reproduction on land.sexual reproduction on land.

Plants that pollinate create seeds as a result.Plants that pollinate create seeds as a result. Seed: A structure that contains a small plant Seed: A structure that contains a small plant

inside.inside.

Seeds!Seeds!

As stated previously, seeds contain immature As stated previously, seeds contain immature developing plants. Since plants make food developing plants. Since plants make food through photosynthesis, and plants in seeds through photosynthesis, and plants in seeds don’t receive sunlight, they need some food don’t receive sunlight, they need some food stored so that they can bust out of their shells.stored so that they can bust out of their shells.

Cotyledon: Leaves in seeds that store food for a Cotyledon: Leaves in seeds that store food for a developing plant.developing plant.

Germination: When a juvenile plant breaks out Germination: When a juvenile plant breaks out of a seed.of a seed.

Classifying PlantsClassifying Plants

Hundreds of thousands of plant Hundreds of thousands of plant species exist in the world today.species exist in the world today.

Scientists informally group Scientists informally group plants into two major groups:plants into two major groups: Nonvascular plantsNonvascular plants Vascular plantsVascular plants

Nonvascular PlantsNonvascular Plants

Nonvascular PlantsNonvascular Plants: Plants that lack a system : Plants that lack a system of tubes for transporting water and other of tubes for transporting water and other materials.materials.

Characteristics of nonvascular plants:Characteristics of nonvascular plants: Low growingLow growing No rootsNo roots Obtain water and materials directly from their Obtain water and materials directly from their

surroundingssurroundings Because they get things directly from their Because they get things directly from their

environments, they usually live in damp, shady environments, they usually live in damp, shady places.places.

Vascular PlantsVascular Plants

Vascular PlantsVascular Plants: Plants with true vascular : Plants with true vascular tissue.tissue.

Characteristics of vascular plants:Characteristics of vascular plants: Better suited to live in dry areasBetter suited to live in dry areas Can grow tall due to extra support of vascular Can grow tall due to extra support of vascular

systemsystem More efficient at moving materials through their More efficient at moving materials through their

bodiesbodies Often obtain nutrients and water from soil with Often obtain nutrients and water from soil with

rootsroots

Vascular PlantsVascular Plants

Unlike non-vascular plants, vascular plants Unlike non-vascular plants, vascular plants have roots to allow them to absorb water have roots to allow them to absorb water and nutrients from the soil, as well as and nutrients from the soil, as well as anchor them in place. Roots need to anchor them in place. Roots need to burrow deep into the ground, so they have burrow deep into the ground, so they have special tissue to protect them as they do.special tissue to protect them as they do.

Root cap: Protective layer around the Root cap: Protective layer around the roots of vascular plants.roots of vascular plants.

Complex Life CyclesComplex Life Cycles

Plants have complex life cycles that include Plants have complex life cycles that include two different stages, the sporophyte stage two different stages, the sporophyte stage and the gametophyte stage.and the gametophyte stage.

Sporophyte StageSporophyte Stage: Stage where plants : Stage where plants produce tiny spores that grow into a new produce tiny spores that grow into a new organism.organism.

Spore: Tiny cell that can grow into a new Spore: Tiny cell that can grow into a new organism.organism.

Gametophyte StageGametophyte Stage: Stage where the plant : Stage where the plant produces sperm and egg cells.produces sperm and egg cells.