Adaptations Of Plants (2nd Ed, 1989)

[Music] thank you foreign there are many different  kinds of green plants different in size and shape and in several other ways these  differences are called adaptations adaptations help each kind of living  thing to survive in its own environment in order to understand the many different  adaptations of plants we first need to remember one way in which all green plants are alike all  green plants are able to make their own food that means a green plant is different  from a fungus like the mushroom a fungus is sometimes considered to be a plant  but it can't make food the way a green plant does usually the leaves are where  most of the food is made a green plant combines carbon dioxide  gas and water to make a simple sugar to do that the plant needs energy  and it gets that energy from light all green plants make food in the same  way but each type of plant also has other special adaptations some adaptations  help a plant to grow in a particular place some plants are especially adapted to a water  environment water lilies and some other plants depend on the water to support their weight  a water lily has large leaves adapted for floating on the surface of the water where they  can collect the light energy needed to make food there are many other plans that are  adapted for growth in most places on land most of these plants have stems that are  strong enough to support their weight there are some plants like this  morning glory that have weak stems but these stems have an adaptation that  helps them find some other kind of support this action is being speeded up in the camera  the stem moves back and forth until it touches something and then it winds itself around  the object and uses it for support [Music] because each kind of plant has its  own special adaptations it's possible for many different plants to grow in the  same surroundings in a forest for example a tall tree has a large stem or trunk  and so the leaves of these trees are raised high above the ground where they  could receive plenty of direct sunlight some plans are adapted for growth in the shade  of the trees these plants usually have larger thinner leaves that's an adaptation that  helps them to collect more light energy forest plants like these can grow only in  places where there is plenty of rainfall but there are other plants that are  adapted to the dry climate of the desert most kinds of cactus have no leaves at all  and that helps to save water large leaves would give up too much water to the air but even  without leaves a cactus is able to make food the food is made in the stem and because the stem is  soft and spongy it can also store a lot of water these adaptations help a cactus plant to  survive for several months Without Rain when a rainstorm does come to the  desert it usually doesn't last very long but a cactus has roots that spread out underground  for a long way even though they don't go very deep that means the roots can soak up a  lot of water in just a short time so desert plants like the cactus  are adapted to a very dry climate in the temperate climate region plants have  special adaptations for survival in winter during Autumn as the hours of daylight grow  shorter many trees form a waterproof seal at the base of each leaf when that happens  the leaves change color and begin to fall that's an adaptation that helps this kind of  tree to stay alive in winter large leaves like this lose a lot of water to the air and in Winter  the tree will need to save all the water it can some trees like this Pine have small narrow  leaves called needles and these trees can stay green all year long because the needles are  so narrow they don't lose much water to the air so trees like this are able to  make food even during the winter some other plants like the chrysanthemum have  a different adaptation for survival in winter parts of the plant the parts above the ground  will freeze and die when cold weather comes the parts underneath the ground will usually  stay alive and start to grow again in Spring so plants are adapted in various  ways for survival through the winter and gradually the days become longer and warmer  soon the trees will begin to produce new leaves but in early spring the leaves are too small  to block the sunlight from the ground below some plants like the may apple are adapted to begin growing early in spring when they  can receive plenty of direct sunlight as the days pass the leaves of the trees grow  larger and they cast their Shadows on the ground now many other plans have appeared plants adapted  for growth without as much direct sunlight we've seen several ways in which different plants  are adapted for growth in a specific place and a specific climate there are other kinds of  adaptations that help to protect plants from animals especially from insects without this  protection plant life could easily be destroyed entirely by plant-eating insects some plants like  the milkweed produce chemicals that are poisonous to most animals only a few kinds of insects  are able to feed safely on milkweed leaves this monarch butterfly caterpillar has an  adaptation that protects it from the poison but most other animals avoid the milkweed  plant and so the plant is able to survive plants like cabbage also make a chemical that's  poisonous to most insects of course people can eat cabbage without getting sick that's because  we don't have the same body chemistry as an insect a cactus plant has another kind  of adaptation for protection its sharp spines help to prevent  most animals from eating the cactus some other plants like roses have thorns  that help to protect the plant from animals the mimosa plant has thorns and it also  has another adaptation for protection watch what happens when something touches a  leaf this adaptation helps to bring the leaves closer to the thorns any animal that tried  to eat the leaf would run into the thorns grass Plants provide food for many animals but  usually those animals don't do any permanent harm to the grass plant that's because grass has an  adaptation that helps to keep the most important parts from being destroyed the growing part of  a grass blade is down very close to the ground where it won't be eaten by most grazing  animals so even though most of the grass blade is eaten the growing part is protected  and it can replace the parts that are lost so some adaptations help to prevent  plants from being destroyed by animals there are other adaptations that  help plants to reproduce themselves we're watching the seed of a pine tree beginning  to grow with the action speeded up in the camera most plants grow from seeds that's a form of  sexual reproduction [Music] the reproductive parts of a pine tree are in the cones that hang  from the branches there are two kinds of cones these cones are male and they produce  pollen which contains the male sex cell the pollen is a loose powder that can be  carried by the wind to the female pine cones when that happens the female cones produce seeds there are several kinds of trees that make  seeds in Combs but most plants don't have cones most plants have flowers instead and the flowers  are where the reproductive parts are located some plants like this rice plant have  small flowers that aren't very colorful this kind of plant depends on  the Wind to carry its pollen but many plants have large beautiful flowers this  action is being speeded up in the camera [Music] the color and shape of the flower are important  adaptations that help the plant to reproduce itself plants like this depend on certain kinds  of animals to carry their pollen and their flowers could be seen easily by insects or Birds the  flowers also produce a sweet liquid called nectar nectar is used as food by some  birds including the hummingbird and some insects also feed on nectar these  flowers make a pollen that is very sticky when an insect or bird comes looking for nectar  the pollen will stick to the body of the animal then when the animal visits another flower of the same kind some of the pollen will rub off  and the plant will be able to make seeds some flowers like the vetch are adapted to  take advantage of the body shape or habits of a certain insect or bird a bee usually  lands on the lowest Petals of a flower and when those petals are pressed down the veg  flower releases pollen some of the pollen sticks to the bee and will be carried away  to another flower of the same kind all right the shape of an iris flower helps to make  sure that its pollen will be carried away a bee has to crawl deep into the  flower in order to get the nectar this means that the bee is sure to rub against  the parts of the flower that make pollen because of a plant last for only a short time  when the plant is ready to make seeds parts of the flower Wilt and fall off the part that's  left will grow into the fruit of the plant inside the fruit are the seeds  that can grow into a new plant some plants produce their flowers only in Spring  some only in summer and some only in autumn that means that all of the plants are  not competing at the same time for the attention of the animals that carry their pollen and so we've seen several different adaptations of  plants adaptations that help a plant to reproduce itself adaptations that help to protect  plants from being destroyed by animals and adaptations that make it possible for  a plant to grow in a certain kind of place many different kinds of plants can live  together in the same surroundings because each kind has its own adaptations that  help it to survive in its own special way foreign [Music] foreign [Music]