Simple eye in invertebrates

In invertebrates, some animals have a simple eye that works a bit like a camera. The eye has a lens that captures light and focuses it onto a group of cells that can detect it. These cells are called photoreceptors.

When the light hits the photoreceptors, it causes a chemical reaction that sends an electrical signal to the animal's brain. The brain then interprets this signal as an image.

Simple eyes are not as good at seeing details as the compound eyes found in many insects, but they are still useful for detecting light and dark, which can help the animal navigate its environment. Some invertebrates, like some snails and worms, have simple eyes that can only detect light and dark, while others, like some spiders, can see shapes and movement.

Overall, the simple eye is a basic yet important tool for many invertebrates to sense their surroundings and avoid danger.