Download Animal and plant adaptations to the rainforest|A1

Animal and plant adaptations to the rainforest| A1
Sample answer
Examine how plants and animals adapt to soils and climate
in a region you have studied. (2007 Q 18)
A biome I have studied is the tropical rainforest biome. An example of a tropical rainforest would be the
Amazon in Brazil. The climate in this region is tropical, which means it is hot, wet and humid all year
around. The region receives almost 12 hours of sunlight every day and the average temperatures are high,
often over 27 degrees Celsius. There are no seasons and the temperature hardly varies from summer to
winter. An average of 1250-6600 mm of rainfall falls in the rainforest each year. This leads to high humidity
levels of between 77% and 88%.
Plants have to adapt to live in this climate. Since there are large quantities of rain, plants must cope with vast
amounts of water falling onto their leaves each day. There is an average of 30mm of rainfall each day which
is more than many countries get in a year. Plants must also cope with harsh fungal attacks as fungus
flourishes in humid conditions. Plants have made adaptations that help them to shed water off so their
branches don’t get laden with water and break. Many of them have flexible leaves that bend easily to
accommodate this. Others have holes and drip tips to funnel water out while others have grooved water
channels that leads water to their roots. Some leaves have oily coatings to repel water and resist fungal
attack. Due to there being so many layers of plants in the dense forest, only 3% of sunlight reaches the forest
floor. Leaves of plants down there tend to be large and wide to absorb as much light as possible on the floor.
In the canopy layer, however, nearer the top, there is more wind so leaves tend to be smaller and narrower
and pointed to reduce drying. Plants have adapted to lack of sunlight and many have large leaves when they
ar saplings which shrink as they grow taller and reach the canopy layers.
Animals also adapt to climate. As climate had produced a layered forest of tall trees, many animals have
adapted their body structure to living in these trees. They travel between trees and must be good jumpers,
climbers of fliers in order to survive. Flying squirrels, for example, have evolved to have flaps of skin
joining their front and back legs. This allows them to jump between trees and glide for longer distances than
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Animal and plant adaptations to the rainforest | Sample answer
they could normally leap. Also, having a tail that can wrap around a tree branch, called a prehensile tail, is
useful for living in trees. Lemurs and spider monkeys have these tails. Some animals like the sloth also have
hooked claws to help them grip the branches that they hang from. They also have large eyes so they can see
with the lack of sunlight on the forest floor. Their fur grows down from their bodies, unlike other animals,
so the heavy rainfall runs off of them when they hang upside down from their branches.
The soil type in this region is latosol. Rapid, deep chemical weathering and leaching play an important role
in its formation. The latosol is poor in nutrients and any it does have are located in the O and A horizons.
Because of this, there is a short nutrient cycle. It takes only a few days for organic matter to be converted
into humus which is then quickly absorbed by plants.
Plants in the region have adapted to surviving in this poor soil with a short nutrient cycle. Because of this,
plants have a shallow root system. In order to support the tree as it grows incredibly tall and to gather
nutrients that only reside close to the surface, many trees form buttress roots. Other trees grow their roots
down from their branches to the ground in order to give themselves the support to grow taller; these are
called stilt roots. Many plants in the upper regions have aerial roots. These are called epiphytes. The roots
use moisture in the air to survive. Their sponge like roots absorb moisture for later use. Plants like orchids
grow high in the canopy and their roots never even touch the ground. This is adaption because the soil does
not have enough nutrients to cater for all these plants so epiphytes do not have to compete for nutrients in
the soil.
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Animal and plant adaptations to the rainforest | Sample answer