The adaptation of plants
This chapter will look at the way that plants can be threatened in their environments. It will also consider how plants can adapt in order to survive and grow.
Needs for survival
Plants have several basic needs for survival. These needs include light, water, air and minerals or nutrients. They also need to be able to reproduce in order to ensure that their species survives. Some of the main threats to the survival of plants include a lack of sunlight, a lack of water, an abundance of water and the activities of animals.
Lack of sunlight
Plants need sunlight to make food through the process of photosynthesis. This means that in areas where there is not a lot of sun, many plants may have to compete in order to get as much sun as possible. Plants in forests may grow a lot of leaves in order to convert as much energy as possible into food.
In forests where the trees lose their leaves every autumn, some plants at ground level may develop and grow flowers early in spring before the trees have grown their leaves back. In tropical forests where the trees keep their leaves all year round, some plants climb up the trunks and branches of the trees in order to reach the light. See image 1
There are even some plants that have leaves adapted to be able to carry out the process of photosynthesis with less sunlight than usual.
Lack of water
Many plants have adapted to life in regions where water is scarce. Some plants in these areas may grow very long roots that reach water stored under ground. Other plants, like cacti, have developed ways of storing water and using the water they have stored very slowly.
There are some plants in desert regions that have very short lives. These plants will begin as seeds that do not grow until rain has fallen. When it does rain they can grow, flower and produce seeds for the next generation of their species all in a few days. See image 2
Abundance of water
There are some plants that live in aquatic environments. This can include plants living in ponds and lakes. One of the main problems for plants that live in water is that it can be hard to get enough light for photosynthesis. Some plants have adapted by growing wide leaves that float on the water, others have grown long stems where the tops stand out of the water. See image 3
One of the other problems some plants can have in watery environments is that they may not be able to draw enough oxygen from the air. Plants need oxygen to break down food that they have stored and use it to grow.
In order to obtain oxygen some plants have developed special stems that act like funnels, drawing oxygen down to their roots.
Activities of animals
A lot of plants are seen as food by many animals. From elephants all the way down to ants, plants are eaten by all sorts of animals but if all of a plant was eaten, it obviously would not survive. This is why many plants have adapted to be able to defend themselves from animals.
Some plants will grow thorns or prickles to keep animals from getting too close to them, or being able to eat them completely. Other plants may have a poison in their leaves or stems that animals learn to avoid. Some will cause a skin irritation or rash if they are touched.
Some plants, like grass, will actually grow new leaves underground and when they are fully developed they will reappear. This allows the plant to survive even though the leaves are eaten time after time.
Sometimes plants are threatened by natural disasters. There are many plants and trees in Australia, for example, that have adapted to survive bushfires. Some of these adaptations include having leaves that burn quickly, but leave the main part of the tree unharmed and being able to sprout new leaves all over the trunk of the tree in order to restore the tree to health as soon as possible.
Plants can also be threatened by the activities of humans. These can include things like pollution and the clearing of land in order to build farms and homes.
We can see that there are many challenges that plants face in order to survive. How well plants adapt to their changing environments will determine their future. It is important to remember, however, that almost all other living things rely on plants in some way and so we all rely on plants being able to adapt to their environments as well.