BBC Bitesize – tropical rainforests
BBC Class Clips – tropical rainforest structure
BBC Bitesize – flora and fauna in tropical rainforests
Water and nutrient cycles
Climate
The daily temperature is about 28C. It never goes below 20C and rarely above 35C. It is a very wet climate, at least 2000mm of rain falls a year. This makes the atmosphere very hot and humid. There are no real seasons. Each day’s weather is the same – starting off hot and dry, with thunderstorms and heavy rain in early evening.
Soils
- The soils are red in colour and rich in iron.
- They have a thick layer of litter (dead leaves etc) as trees drop their leaves all year round but only a thin fertile layer because the leaves decompose very quickly in the humid conditions.
- The soils are not very good for plants to grow in as nutrients are quickly washed out (leached) of the soil because of heavy rainfall.
- Trees and other vegetation have roots close to the surface, where the nutrients are – there are lots of roots in the humus layer
Flora
- The vegetation in rainforests grows in distinct layers and has adapted to the climate and poor soils.
- Trees are very tall and trunks are thin to reach sunlight.Buttress roots support these tall trees in shallow soils.
- Lianas are woody vines that climb high to reach the sunlight.
- Leaves in the tropical rainforest have drip tips to allow rainfall to drip down to the lower layers and shed heavy rainfall easily.
- Lack of wind near the foerst floor means that many plants have to rely on bees, butterflies or other animals for pollination.
Fauna
- More animal species than any other ecosystem
- Gorillas, jaguars, anacondas, tree frogs and sloths
- Lots of species of insects and birds
- Many animals are camouflaged e.g. leaf tailed geckos look like leaves so they can hide from predators.
- Some animals are nocturnal (active at night) e.g. sloths. This is so they can sleep through the day and feed at night when it’s cooler – this helps them to save energy.