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-A 200-year-old tree shaded the forest floor throughout its life.- When it falls in a storm, the forest floor will receive much more sunlight.
Seedling that require a lot of sunlight will have a chance to grow.
Other plants that grow best in shade might not survive .
Ecosystem change
The change may affect animals too. Birds that nested in the tree may need to find new home.
but the fallen tree may provide habitat for salamanders and other animals .
Living things cause change
People cut down trees to build homes. -They clear land in order to grow food in open fields. People are living things that cause change in their
environment .
The groundhogs live underground in tunnels, or burrows.As they dig their burrows, they change the environment.
-Some living things benefit from changes that groundhogs cause. -Foxes, rabbits, and other animals live in burrows made by groundhogs.
-Fires can burn forests.-Hurricanes can wash away beaches and knock down trees. They can cause floods.
Natural Events Cause Change
Droughts can change ecosystems.During drought, very little rain falls.Plants die from lack of water.
If animals cannot find enough water, then they may die or move to other places.
Not all living things are harmed by changes to ecosystems. A forest fire may destroy trees and animals'
homes.1- But the fire also clears dead plants and wood from the forest floor. Then trees have more space to grow. 2- Plants that need more sunlight can also grow. Ash from the fire makes soil healthy. Ash contains minerals that plants need
Seasonal change
In some ecosystems, the cycle of the seasons brings major changes.
- Summers may be warm, but winters may be very cold and snowy.- Some plants die in winter.- Food may be hard to find for
some animals .
Many plants and animals have adaptations that help them survive these changes.
Adaptation is a trait that helps a living thing survive in its environment.
Trees shed their leaves before winter. This reduces the amount of water
they need to take in during winter .
The volcano Mount St. Helens erupted in the state of Washington. This eruption was huge. The blast changed the
ecosystem .
Living things Return
1 -It knocked over trees.2- It burned whole forests and killed many animals.3- Rivers of mud covered large areas.4-The volcano released a cloud of ash into the air.5- Winds carried the ash around the world.
over time, however, wind carried the seeds of grasses, flowers, and trees to the mountain. new plants began to
grow .
Spiders and beetles arrived. Birds returned to live in the standing dead trees. Small and large mammals also returned.
Each new change allowed more kinds of plants and animals to live there again.The ecosystem is not the same as it was before the eruption. But it is covering.