Placeholder Image

Subtitles section Play video

  • You're watching FreeSchool!

  • Plants are living organisms.

  • They come in many different shapes, sizes, and colors, but they all need air, water,

  • nutrients, and sunlight to live.

  • Plants cover much of our planet.

  • Every blade of grass, tree, flower, bush, fern, or moss you see is a plant.

  • Large or small, on the land, or in the sea, from forests to deserts, plants are almost

  • everywhere!

  • Plants are so important to life on earth that without them, we could not survive.

  • Plants create food from the sun's energy, and form the foundation of nearly every food

  • chain on the planet.

  • Plants produce the oxygen in the air we breathe, helping animals to stay alive.

  • Plants also create important habitats where animals can live, and provide humans with

  • many natural resources.

  • So what makes something a plant?

  • Plants are special on the cellular level.

  • They are always made of more than one cell - meaning there are no single celled plants

  • - and their cells have specal parts.

  • One special part of a plant cell is the cell wall.

  • Cell walls are rigid and unbending.

  • Since plants do not have skeletons, these cell walls give them their structure.

  • Without cell walls, tall trees, cactus and even little flowers would not be able to stand up!

  • Many plants are easy to recognize by their green leaves - in fact, most plants are green,

  • or have green parts.

  • This green color is caused by another special part of their cells called chloroplasts.

  • Chloroplasts contain chlorophyll, which is green.

  • Chlorophyll is what allows plants to carry out photosynthesis and make food from the

  • sun's energy.

  • During photosynthesis, plants use the sun's energy to change water and carbon dioxide

  • into a kind of sugar.

  • They use this sugar to grow and develop, and store the extra in their leaves, roots, or

  • fruits.

  • In addition to sugar, plants produce oxygen during photosynthesis.

  • Since plants do not need the oxygen, they release it into the atmosphere, where animls

  • and people can breathe it in!

  • Plants cannot move the same way that people or other animals do, so they have to have

  • special strategies to solve their problems.

  • For example, some plants cannot get enough nutrients from the soil they are growing in.

  • The plants of eastern North American bogs have adapted to their nutrient-poor soils

  • by getting extra nutrition from an unusual source - insects.

  • One of these carnivorous plants, the sundew, has sticky fluid coating special hairs.

  • This fluid has a sweet smell that attracts insects.

  • When an insect lands on the hair, however, it becomes stuck - trapped by the plant - and

  • the fluid digests the prey, breaking it down into nutrients.

  • Another kind of carnivorous plant is the pitcher plant.

  • The 'pitcher' of the plant is a modified leaf that is watertight.

  • The plant fills it with a combination of nectar and digestive juices.

  • The smell of the nectar and colors at the edge of the pitcher attract insects and other

  • small visitors, but once inside the prey find it too slippery to get out again and will

  • fall into the pool at the bottom of the pitcher, where they are digested.

  • The most famous carnivorous plant is the Venus Flytrap.

  • It has specialized leaves that act like the mouth of the plant.

  • Like the other carnivorous plants, its bait is sweetened nectar.

  • Once prey climb onto the leaf, they activate the trigger hairs which signal the plant to

  • close its trap.

  • Long guard hairs interlock across the top of the leaves, preventing escape, and the

  • prey is slowly digested.

  • Unlike carnivorous plants, which are predators, most plants are prey for herbivores.

  • They have developed strategies to help protect them from being eaten.

  • One popular strategy plants like to use is to grow thorns, spines, or prickles.

  • The cactus is famous for its sharp spines.

  • Most cacti live in the desert, where water is a scarce and precious resource.

  • Cacti store water in their thick, waxy stems.

  • To prevent animals from consuming their carefully collected resources, they grow sharp spines

  • which deter all but the hungriest - or most cautious - of animals.

  • A plant with another interesting defense is the sensitive plant.

  • When its leaves are touched, they close up.

  • This makes the leaves look dead, or wilted, and may send a hungry herbivore searching

  • for a more tasty-looking lunch.

  • Finally, a popular plant defense strategy is to use chemicals to protect themselves.

  • Some plants just use chemicals to give their leaves a bitter taste.

  • Other plants have chemicals on them that can make us itchy!

  • Still other plants are poisonous, making animals that eat them get sick or even die.

  • Animals learn not to eat these poisonous plants and the plants can then grow undisturbed.

  • One more problem that plants have to solve is the problem of how to get their seeds away

  • from them.

  • Plants do not want their seeds to grow right next to them, because then they would be competing

  • for the same resources.

  • Some plants use the wind to spread their seeds.

  • Some plants that live near water have seeds that can float, and let the water carry their

  • seeds away.

  • A popular method plants use to spread their seeds is to have animals carry them away.

  • Some seeds, called burs, grow with hooks on their outsides.

  • These hooks get caught on the fur of passing animals and are carried away to new areas.

  • Other plants grow their seeds inside fruits or berries.

  • Animals eat the fruit and it is digested, but the seeds pass through unharmed and are

  • dropped far away from the parent plant.

  • Still other seeds, like acorns, are collected by animals that bury them.

  • Not all of these buried seeds get eaten, leaving some to grow into new trees.

  • Some plants, however, take matters into their own hands - or seed pods, that is.

  • When touched or tapped, the fruit of the exploding cucumber splits open forcefully, spreading

  • its seeds in one burst.

  • On the land or in the sea, plants play a critical role in in the continuation of life on earth.

  • They make their own food from sunlight, converting it to food that animals can use.

  • Plants produce oxygen for us to breathe and habitats for animals to live in.

  • No matter where they grow, or what challenges they face, plants have learned how to get

  • enough nutrients, protect themselves from hungry animals, and spread their seeds around.

  • Plants are incredible!

  • I hope this helped you learn more about plants today.

  • Goodbye till next time!

You're watching FreeSchool!

Subtitles and vocabulary

Click the word to look it up Click the word to find further inforamtion about it