Plant Adaptations Tropical Rainforest

Plant Adaptations Tropical Rainforest

Mr. Peeden 6th Gr. Science Webb School of Knoxville

● Strong root systems allows regrowth after grazing, trampling by herbivores (Bison).
● Above ground growth dies and decays making rich soil.

Grassland

Many plants have roots that grow deep in the ground, where the most water can be found. This defense also allows the plant to survive fires because the root is undamaged and can regrow after the fire.

Savanna

Review From Monday

Open Ended

What did you learn from the video? (2-3 sentences)

​Rainforest Structure

​Many of the tall trees in a rainforest shoot straight up and only have branches and leaves near the very top.

With tons of trees packed in like this, the tree tops create a blanket of leaves hundreds of feet above the forest floor. This leafy layer of the forest is called the canopy, and it blocks out most of the sunlight, shading the layers underneath.

As we look at the trunks of the trees, we find vines that start in the ground and wrap around the trees. Sometimes these vines reach from the base of the tree all the way up to the sunlight in the canopy.

However, a special vine called a strangler fig starts from the canopy and reaches down to the ground. Other plants called epiphytes can also grow without ever touching the ground—they attach their roots to tree branches instead of soil.

If we keep going down to the shaded lower levels of the forest, called the understory, we find fierce competition among the plants that are trying to grow. These plants depend on sunlight to grow, but with so much shade from the canopy, areas with sunlight can be hard to find.

Sometimes, when a large tree dies and falls over, a light gap is created and sunlight hits the forest floor. In the spots of light on the forest floor, young trees called saplings that may have been struggling to survive in the shade for 20 years or more will use the opportunity to grow quickly and try to reach more sunlight in the canopy.

​Rainforest Structure Cont.

When we reach all the way down to the forest floor, hundreds of feet below the canopy, we find a thin habitat made of leftovers from other forest layers.

Leaf litter covers this bottom layer of soil. Any dead plant or animal material that falls to the floor becomes food for fungi or bacteria. In a day or two, these microorganisms can break down a leaf or a banana peel into small bits and pieces we call nutrients.

With so many plants on the forest floor that need these nutrients to grow, the nutrients have no chance to sink down deep into the soil. This means that most plants must have roots that are shallow to grab the nutrients as they are formed. This is just one example of many special tricks, called adaptations, which plants use to survive.

Powerful Plants

Of all the Earth’s land biomes, rainforests change the most amount of energy coming from the sunlight into food (like sugars). We call this action photosynthesis.

After plants change sunlight energy into sugars, animals can get that energy by eating the leaves, fruits, or other parts of the plants. This can be good or bad for the plants, so over many, many years, plants have come up with ways to trick animals into eating certain plant parts while avoiding others.

A Sweet Trick

Plants pack their fruits with sugar, making them a sweet and tempting treat for many animals. This is because fruits also hold the seeds of a plant. 

By hiding their seeds in delicious fruits, plants are tricking animals into eating them. That way, the animals spread (disperse) the seeds inside the fruits to other areas of the rainforest.

But what about the parts of a plant that need to be protected and not eaten? To fight off animals like insects that try to eat their leaves and shoots, some plants make certain chemicals called toxins. These toxins taste bad or make animals sick, so animals will not eat those parts of the plant.

Plant Protection

When you compare the plants of the rainforest to those in other biomes you begin to see one big difference, the leaves. Most of the plants have large leaves and some you could say are huge. They also have a particular shape. They come to a point that is called a drip tip. This shape helps to direct the water to specific locations.

Leaf Design

Rainforest Continued

Epiphytes are plants that live on other plants. They don’t have roots in the ground, and have evolved various strategies for obtaining water and nutrients. Sometimes a single tree can be home to many different epiphyte species, together weighing several tonnes. Epiphytes even grow on other epiphytes!

Epiphytes

Orchids in the rainforest are often epiphytes. Some have specially adapted roots that enable them to capture water and nutrients from the air. Other orchids have roots that spread out over the branch of the host tree, capturing water without needing to bury into the ground.

Orchid

The açai is thought to be the most common tree in the Amazon Rainforest. Despite this, it still makes up only 1% (5 billion) of the 390 billion trees in the region. Its fruit is edible, and an important food in the Amazon region.

Acai Palm

The Amazon water lily is an aquatic plant that grows in the lakes and rivers of South American rainforests. Its huge leaves can be up to 3 metres (9.8 ft.) in diameter. There are rows of sharp spines on the undersides of the leaves. These deter rainforest animals such as manatees from eating them.

Amazon Water Lily

Summary: Shallow roots, large trees with broad leaves, grow on varied levels of the forest due to varied levels of sunlight

​Now that you have finished, please make sure your notes are updated. Then, grab a copy of the doodle notes at the front of the class, use the linked slides on our week at a glance, and complete. THESE ARE NOT HOMEWORK!