Plants and animals in a tropical rainforest
Chapter summary
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There are approximately 3000 plant species from 210 different families in the rainforest.
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The roots of rainforest trees do not grown deep down into the ground; instead, they spread out. This is because the soil in rainforests is not very deep.
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Epiphytes are air plants that live on other plants but make their own food.
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Parasites live on other plants and do not make their own food.
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Saprophytes obtain their nutrients from the dead organic matter on the forest floor.
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The diversity of a rainforest is due to its age, which has allowed life to evolve and develop in a specific environment.
Plants
Rainforests have a diverse range of plant and animal life. There are approximately 3000 plant species, from 210 different families in a rainforest. There are very few flowers on the forest floor, because there is so little sunlight at this level. There are several ways that plants under the canopy receive sunlight. One way is by living off the trunks and branches of trees. Light is also seen for a period of time when one of the large canopy trees or emergent trees falls to the ground, clearing a large area. When this happens, the smaller trees grow rapidly towards the light and compete to fill the space.
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The roots of the tall trees in a rainforest do not grow deep into the ground. They spread out across the floor of the forest to make a sturdy base. The roots of these trees spread out, rather than down, because rainforest soil is quite shallow. This means that the roots have to stay near the surface in order to absorb nutrients from the soil. See image 1
Lianas
Lianas are a type of climbing vine. These vines climb the trunks of the larger trees to try and reach the sunlight. They often loop up and down in this process. They are very thick vines that are sometimes used to make bridges. They are also used to make baskets because of their fibrous nature. See image 2
Epiphytes
Epiphytes are air plants. They live in the air while resting on another tree and do not enter the soil. These plants thrive on the branches or trunks of other plants. These plants do not damage their hosts. They take their food from the environment. Many epiphytes are flowering plants. In a temperate rainforest, common epiphytes are ferns and mosses (see image 3), while tropical rainforests have many different species.
Parasites
In a rainforest, parasites are tropical vegetation that cannot live on their own. Parasites cannot make food from the sunlight. Instead, they take their food from the plant to which they have attached themselves. Many of the forest fungi are parasitic. See image 4
Saprophytes
Saprophytes need almost no sunlight. Like parasites, they cannot make their own food. Unlike parasites, however, they do not live off other plants. Saprophytes in a rainforest obtain their nutrients from the dead organic matter on the forest floor. See image 5
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Animals
There are so many animals in tropical rainforests that some of them have not been studied or even named yet. Tropical rainforests are home to about half of all the world's species. Scientists say that the diversity in tropical rainforests is partly due to their age. Some rainforests have been around for millions of years. This means that for millions of years the plants and animals in tropical rainforests have been evolving and developing to create an incredibly diverse and complex system. The animals in a rainforest live in the layer that is best suited to their abilities and their needs, with the canopy having the most life. Animals in a tropical rainforest occupy all the layers that make up this unique environment. In a temperate rainforest, most of the animals live on or near the forest floor.
There is an enormous variety of mammals in a rainforest. Mammals are animals with fur that feed their babies with milk (see image 6). The rainforest is also home to birds of every colour. Reptiles, which have scales and lay eggs, also live in the rainforests. Amphibians, like frogs and toads, live in and out of water. It is the insects of the rainforest, however, that you would be most likely to see if you were to walk around.
The emergent layer
The emergent layer is home to animals with a remarkable sense of balance and no fear of heights. Birds in the emergent layer range from parrots to vultures and eagles (see image 7). Macaws are brightly-coloured birds with powerful beaks. The king vultures eat dead animals, which helps to keep the jungle clean. One of the world's biggest eagles, the Philippine eagle, lives on monkeys that it picks off the branches of the rainforest's trees.
The canopy
The canopy is home to the largest number of animals in the rainforest. Squirrel monkeys are small and can travel quickly among the trees. They live in big groups and eat insects, lizards, fruit and sometimes birds' eggs. Squirrel monkeys also sometimes live in the emergent layer. Other monkeys in the canopy include gibbons, spider monkeys (see image 8) and Mona monkeys. Sloths are slow-moving animals that spend most of their time hanging upside down in a tree. A sloth will descend its tree to go to the toilet, which it takes about an hour to do (see image 9). Green iguanas have a timid nature and are good climbers with sharp claws and powerful toes. Green tree pythons squeeze and suffocate their food; they mostly eat monkeys and birds.
Watch the video on the Monkey
The understorey
The understorey is hot and humid. The king of the Amazon is found in the understorey. This is the jaguar, the biggest cat in the jungle (see image 10). Chameleons are colourful lizards that change colour to merge with their surroundings. This is a survival tactic, as it makes it very difficult for a predator to see them. Tree frogs need a lot of water, and they hide in damp places to conserve their heat (see image 11).
