Plants

LS4 3.08

Plants are organisms.

Plants are the type of organism that can produce their own food, unlike animals. Animals must consume other organisms for the energy they need.

Plants produce food energy in a process called photosynthesis.

Three things are needed by plants in order for photosynthesis to occur.

Light from the Sun

Light from the Sun

CO2 from the air

Light from the Sun

CO2 from the air

Water from the plants roots

Notes:

What is the process called in which plants make food?

Notes:

What is the process called in which plants make food?

Photosynthesis

Notes:

What three things must plants have in order to make food?

Notes:

What three things must plants have in order to make food?

Notes:

Light

CO2

water

Plants need small amounts of other substances (vitamins, minerals) to do their best work. Plants get these nutrients from the soil.

What do we call the small amounts of vitamins and minerals that plants get from the soil?

Notes:

What do we call the small amounts of vitamins and minerals that plants get from the soil?

Notes:

Nutrients

Plants don’t live forever. They grow old and die like every other organism.

Plants would disappear from Earth unless they reproduce. “Reproduce” means to make more of the same.

The way most plants reproduce is by making seeds.

But, before a plant can make a seed, it must get a tiny bit of pollen from a similar plant.

This pollen is magnified many times

Pollen is made in a plant’s flower. Pollen is a fine powder that can blow on the breezes from one plant to another.

But blowing in the wind is not a sure way to get pollen from one plant to another.

Sometimes animals help plants move pollen from plant to plant.

Plants make nectar, a sweet substance, in their flowers.

Pollen sticks to animals as they collect nectar.

Some pollen falls off at the next flower. It just takes a tiny bit of pollen for a plant to make a seed.

Bees are very important in pollination. Without bees there would be a lot less food for people to eat.

How do most plants reproduce (make new plants like themselves)?

Notes:

How do most plants reproduce (make new plants like themselves)?

seeds

Notes:

What must most plants do before they can make seeds?

Notes:

What must most plants do before they can make seeds?

Notes:

Get pollen from a similar plant

What are two ways that pollen gets from one plant to another?

Notes:

What are two ways that pollen gets from one plant to another?

Notes:

• Blown by the wind

Carried by animals

What are two ways that pollen gets from one plant to another?

Notes:

• Blown by the wind

• Carried by animals

What is the most important animal for pollination of plants?

Notes:

What is the most important animal for pollination of plants?

Notes:

Bees

After pollination has taken place, the plants can make seeds.

A seed contains a baby plant together with a supply of food to get it started.

Ungerminated plant

Plant food

seed

After it germinates, the new plant must reach the sun for energy before the

food in the seed runs out.

Some plants produce seeds in ways that make food for animals.

Once again animals can help the plants.

Once again animals can help the plants.

This time, by dispersing seeds so new plants can grow in different areas.

Animals drop some seeds as they move around. Animals help plants by dispersing seeds.

When animals drop seeds it helps the plant reproduce in new places.

What is another way that animals help plants?

Notes:

What is another way that animals help plants?

Dispersing seeds

Notes:

What does the word “disperse” mean?

Notes:

To spread around in different places.

A seed can stay dormant (asleep) for years. They usually won’t wake up unless there is water.

The word for a seed “waking up” and beginning to grow is germination.

Germination is also called sprouting.

After the seed germinates, the stem grows up and the roots grow down.

Some plants send down one strong, deep root called a taproot.

Other plants have a system of many softer roots called fibrous roots.

Here are plants with a taproot and a fibrous root side by side.

taproot fibrous root

Every kind of root has tiny root hairs that absorb water for the plant.

Other plants have structures that store a lot of food energy in their roots. These roots are called tubers.

Potatoes, radishes, and carrots are all tubers.

As plants grow above the ground, the stem holds the leaves up in the air.

The stem has tubes that carry water and nutrients from the roots up to the leaves.

Plants must have light for energy. The stem holds leaves up to get more light.

The leaves must have sunlight to make the food that the plant needs to live and grow.

Leaves also give off water vapor as they make food. This water is called transpiration.

Leaves also give off water vapor as they make food. This water is called transpiration. Bigger leaves give away more water.

What is the word for water vapor that a plant releases through its leaves?

Notes:

What is the word for water vapor that a plant releases through its leaves?

Notes:

transpiration

What are the two words for a seed beginning to grow into a plant?

Notes:

What are the two words for a seed beginning to grow into a plant?

Notes:

• germination

What are two words for a seed beginning to grow into a plant?

Notes:

• germination

• sprouting

What kind of root is strong and grows deep?

Notes:

What kind of root is strong and grows deep?

Notes:

taproot

What kind of root system has a lot of smaller roots?

Notes:

What kind of root system has a lot of smaller roots?

Notes:

Fibrous roots

What are the tiny roots that absorb water?

Notes:

What are the tiny roots that absorb water?

Notes:

root hairs

What kind of roots store large masses of food energy?

Notes:

What kind of roots store large masses of food energy?

Notes:

tubers

Sometimes plants must make changes if they are to survive in their ecosystem.

Such changes are called

adaptations.

A plant in the desert must adapt to very low rainfall and a lot of intense sunshine.

Big leaves that give away a lot of water as transpiration wouldn’t help a plant in the desert.

Desert plants have adapted by developing very thin leaves that don’t give away much water.

Cactus needles are leaves that have adapted to a hot dry environment.

It doesn’t rain much in the desert and when it does rain the water doesn’t soak very deep into the soil.

It doesn’t rain much in the desert and when it does rain the water doesn’t soak very deep into the soil.

Deep roots wouldn’t really help a cactus.

Cactus plants have adapted to this.

Cactus plants have shallow roots, close to the surface, that reach as far out as they can.

This is a good adaptation in a place where rain doesn’t soak deep into the ground.

Big leaves would be a good adaptation where it rains a lot and big trees steal most of the sunlight.

What is the word for a change that an organism makes to help in live in its environment?

Notes:

What is the word for a change that an organism makes to help in live in its environment?

Notes:

adaptation

Trees in different climates have to adapt to their local conditions.

In a tropical rainforest, near the equator, it is always hot and it rains almost every day. Many plants thrive here.

Trees may adapt here by growing very high to catch more sunlight.

Plants that don’t grow high need to adapt with large leaves to catch more of the limited sunlight that makes it down low.

Deciduous forestdee sid jew us

Deciduous forestdee sid jew us Temperate climates are

hot in the summer.

Deciduous forestdee sid jew us

But they can be very cold in the winter.

Deciduous trees adapt to hot summers and cold by having lots of leaves in summer, dropping them all in autumn, and hibernating all winter.

summer winter

Deserts

Most desert trees have adapted by growing near the few sources of water.

Or they have adapted small leaves that don’t lose a lot of water through transpiration.

No trees can adapt to grow in ground that is always frozen.

In the tundra, in the far north and south latitudes, there are no trees.

If an organism can’t adapt to its environment, it won’t survive.