Planaria facts for kids
Quick facts for kids Planaria |
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Tricladida
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Planariidae
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Planaria
Müller OF, 1776
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Planaria are tiny, soft-bodied animals that live in water. They are a type of flatworm. You can find them in fresh water, like ponds and streams. Some kinds also live in very damp soil.
These amazing creatures move in a smooth, wavy way. They are free-living, meaning they don't need a host to survive. Planaria are known for their incredible ability to regrow lost body parts. If a planarian is cut, each piece can grow into a whole new animal!
Contents
What is a Planarian?
Planaria are simple animals, but they have some cool features. They belong to a group called flatworms. These worms are flat and soft, without any bones. They are often studied in science classes because they are easy to observe.
How Planaria Sense Their World
Planaria have a very simple nervous system. It's one of the most basic nervous systems found in animals.
- They have small groups of nerve cells called ganglia. These are like a simple brain.
- These ganglia are located near their eyespots.
- Nerves run down their body, like a ladder.
- Their head is more sensitive than the rest of their body. This helps them find food and avoid danger.
- Planaria have eyespots that can sense light. They usually move away from bright light into darker places.
How Planaria Eat
Planaria have a unique way of eating.
- Their mouth is on the underside of their body.
- When they find food, they release special liquids called enzymes. These enzymes help soften the food.
- Then, they use a tube-like part called a pharynx to suck up the softened food.
- The food goes into their gut cavity.
- From there, nutrients spread throughout their body.
Planaria do not have a separate system for blood or breathing.
- Oxygen enters their body directly through their skin.
- carbon dioxide (a waste gas) leaves their body the same way.
How Planaria Move
Planaria don't have a skeleton. Instead, they use their muscles to move.
- They have special muscles that can stretch and crumple.
- These muscles help them glide smoothly through the water.
- Their body wall has three layers of muscles. These layers help them change shape and move around.
Planarian Reproduction
Planaria can reproduce in two main ways.
- Sexual reproduction: Planaria are hermaphrodites. This means one animal has both male and female parts. They can mate with another planarian. They release eggs and sperm into the water. The eggs then get fertilized.
- Asexual reproduction: This is when a planarian splits into two or more pieces. Each piece then grows into a complete new planarian. This amazing ability to regrow is called regeneration. While they can do this, asexual reproduction is not as common as sexual reproduction.
See also
In Spanish: Planaria para niños
