Question

Sound and Light in Nature

Sound and light are very important in nature. Animals use sounds to communicate. It helps them move around their habitat. Some living things create their own light. These are adaptations. They help living things survive in their environments.


Sound

Birds use calls to communicate. Some of these calls are very short sounds. Others sound like longer songs. Sound travels farther than birds can see. They can call to one another to stay in touch from a distance.


Birds make calls for different reasons. Mother birds have special calls for their chicks. Birds call to warn each other of danger. These calls may be sung to attract mates. Calls can even be used to ask for food.


Birds make calling sounds to communicate with one another.

Some animals move around in complete darkness. A bat is one example of these animals. Bats use echolocation to find their way around. This is the use of sound waves to find nearby objects. Bats send out sound waves. These waves bounce off an object which creates an echo. This echo returns to the bat’s ears. From this echo, they know the object’s location, shape, and size. This helps bats to find food and avoid running into objects.


This diagram shows how echolocation helps a bat locate prey using sound waves.

Light

Most animals need sunlight to see. However, some species can create their own light. This is called bioluminescence. These species can create light because of unique chemical reactions.


Bioluminescence is sometimes found in ocean animals. Sunlight cannot reach the depths of the ocean. Bioluminescence helps some species survive. The anglerfish uses a lighted lure. This sits atop its head. Smaller creatures are drawn to the light. When the prey is close, the angler fish catches it.


About half of all jellyfish are bioluminescent. Most of the deep-sea jellyfish use bioluminescence. It is a defense against predators. Some give off a quick flash of light. This startles their predators. Others create multiple small lights. These confuse the predators. Some jellyfish create a bioluminescent slime. It sticks to predators and makes them easy to spot.


Jellyfish create their own light through bioluminescence.

On warm nights, you may see small lights flashing outside. These flashes are caused by fireflies. This light warns predators not to eat them. Fireflies also use light to attract mates.


Shadows

Shadows are formed when something stops light from reaching an area. Half of the earth is in shadow at a time. When our half of the earth is in shadow, we call it night.


The earth and the moon occasionally line up. This causes an eclipse. A solar eclipse is when the moon blocks the sun. The moon casts a shadow on Earth’s surface. The opposite is a lunar eclipse. This is when the earth blocks the sunlight from reaching the moon.


A total solar eclipse occurs when the moon completely blocks the sunlight from reaching Earth.

Shadows play a role in Groundhog Day traditions. Americans gather every year on February 2. People watch the groundhog named Phil leave his den. If he sees his shadow, he goes back to his den. If so, winter continues for six weeks. If he sees no shadow, he comes outside. This means spring will come early.


Lights and sounds are important to nature. They help animals communicate. They give them ways to protect themselves. People can study light and sound in nature. This helps us to better understand our world.

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Questions
Choose three animals that use bioluminescence.


Some jellyfish


Bats


Anglerfish


Fireflies
Choose two reasons why birds make songs and bird calls.


To call for their chicks


To help them see better


To help them lay eggs


To attract mates
Choose two sentences that are true, based on the text.


Bats use sound waves to find objects that are nearby.


Ocean animals are the only animals that use bioluminescence.


Nighttime happens when half of Earth is in a shadow.


Animals cannot create their own light.
How does bioluminescence help anglerfish?


It helps them see and hear.


It helps them talk to other fish.


It helps them catch small fish to eat.


It helps them grow bigger.

Answer 1

1) Animals that use bioluminescence (choose three):
- Some jellyfish
- Anglerfish
- Fireflies

2) Reasons birds make songs and calls (choose two):
- To call for their chicks
- To attract mates

3) True sentences (choose two):
- Bats use sound waves to find objects that are nearby.
- Nighttime happens when half of Earth is in a shadow.

4) How does bioluminescence help anglerfish?
- It helps them catch small fish to eat.