Using Senses
Essential Question: How are an organism’s senses and sensory organs used to detect signals from the environment?
Sensory Organs
All animals have body parts that get signals from the environment. These body parts are called sensory organs. Your sensory organs are your eyes, ears, nose, tongue and skin. Many animals have sensory organs much like yours. Other animals have different kinds of sensory organs.
An animal uses its sensory organs to notice changes in its surroundings. Then the animal responds in certain ways called behaviors. When an animal senses danger, it acts to protect itself. Animals also use their senses to find things they need, such as food, water, and shelter.
Essential Question: How are an organism’s senses and sensory organs used to detect signals from the environment?
Sensory Organs
All animals have body parts that get signals from the environment. These body parts are called sensory organs. Your sensory organs are your eyes, ears, nose, tongue and skin. Many animals have sensory organs much like yours. Other animals have different kinds of sensory organs.
An animal uses its sensory organs to notice changes in its surroundings. Then the animal responds in certain ways called behaviors. When an animal senses danger, it acts to protect itself. Animals also use their senses to find things they need, such as food, water, and shelter.
Smell
When animals smell, they sense tiny bits of materials in the air. These tiny bits are called odors. When you smell food, your nose takes in odors that the food gives off. Most mammals have a good sense of smell. They use their sense of smell to avoid danger, find food, and recognize other animals. You have most likely noticed that dogs use their noses to learn about everything around the. Not all animals smell using a nose. Insects smell with their antennas. Snakes smell with their noses, but they also gather odors with their tongues. That is why snakes flick their tongues in and out. Fish have a sense of smell, too. They sense odors in the water in the same way you sense odors in the air. Hearing
Animals can sense sounds. Sensing sound helps animals find food, avoid danger, and communicate with each other. Humans and many other animals hear with ears. Fish and snakes do not have openings for their ears. Fish sense sounds through parts of their skin. Snakes sense sounds through bones in their heads. Some animals have hearing organs on other parts of their bodies. Crickets have these organs on their legs. Birds, cats, and dogs have very good hearing. They can hear many sounds that humans cannot hear. |
Sight
Most animals see by using their eyes to take in light. Sight helps animals find food and shelter. Sight helps animals tell one object or organism from another. Many animals see better than humans. Hunting birds, such as hawks, can spot small, moving animals from high in the sky. Cats see better in the dark than humans do. Insects’ eyes are very different from humans’ eyes. Insects do not see clearly, but they see colors that humans cannot see. Some animals, such as moles, cannot see very much. Earthworms can sense light but do not really see. Taste
Most animals have a sense of taste. They use taste to learn which foods are safe to eat. You taste with your tongue. So do many other animals that have a mouth and a tongue. Taste buds on your tongue detect five flavors. These flavors are salty, sweet, bitter, sour, and a meaty flavor called umami (\ü-mä-mē\). Snakes have taste buds near their teeth, not on their tongues. Many insects taste with their feet. An earthworm tastes with the outside of its body. Touch
All animals have a sense of touch, which lets them feel things. Animals feel pressure, heat, cold, pain, and texture. Texture is the way a surface feels, such as rough or smooth. Touch helps animals stay safe, find food, and take care of each other. In humans and many other animals, skin is the sensory organ for touch. Many animals have special hairs growing out of their skin that help them feel things. A cat feels things with its whiskers as well as its skin. Insects have a hard covering instead of skin. They have many small hairs on their bodies that are organs for touch. These hairs let insects sense even tiny movements of air. |
Unusual Senses
Every animal has the senses it needs for its way of life. Some animals have senses that are very different from those of humans.
Some snakes, such as rattlesnakes, can see at night to hunt for food. These snakes have sensory organs called pits. They look like small holes near the snakes’ eyes. Just as eyes take in light, pits take in the body heat of other animals. The snakes can use this information to see the animals they hunt.
Bats use their sense of hearing to find food in the dark. Bats give off sounds as they fly. The sounds bounce back, or echo. Humans cannot hear these sounds, but bats can. The echoes tell bats where to find insects to eat. This way of finding things is called echolocation.
Sharks and fish called rays have electric senses. Some electricity moves through the bodies of all living things. Sharks and rays can sense this electricity. They use their electric senses to hunt other animals for food.
Many animals move from place to place n a pattern depending on the seasons. Scientists think some animals use magnetic senses to find their way. These animals include birds, monarch butterflies, and some whales. Earth acts like a giant magnet. Its pull is strongest near the North and South Poles. Animals with magnetic senses can detect this pull to tell direction.
Every animal has the senses it needs for its way of life. Some animals have senses that are very different from those of humans.
Some snakes, such as rattlesnakes, can see at night to hunt for food. These snakes have sensory organs called pits. They look like small holes near the snakes’ eyes. Just as eyes take in light, pits take in the body heat of other animals. The snakes can use this information to see the animals they hunt.
Bats use their sense of hearing to find food in the dark. Bats give off sounds as they fly. The sounds bounce back, or echo. Humans cannot hear these sounds, but bats can. The echoes tell bats where to find insects to eat. This way of finding things is called echolocation.
Sharks and fish called rays have electric senses. Some electricity moves through the bodies of all living things. Sharks and rays can sense this electricity. They use their electric senses to hunt other animals for food.
Many animals move from place to place n a pattern depending on the seasons. Scientists think some animals use magnetic senses to find their way. These animals include birds, monarch butterflies, and some whales. Earth acts like a giant magnet. Its pull is strongest near the North and South Poles. Animals with magnetic senses can detect this pull to tell direction.
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Synthesis Statement:
Explain how humans and other animals use their senses and sensory organs to detect signals from the environment and how their behaviors are influenced by these signals. |