Select the one animal that has all of the arachnid traits listed above.
White-spotted octopuses have tentacles, which are also called arms. White-spotted octopuses can use their tentacles to reach between corals and grab fish. These octopuses have a soft red body with white spots. Leaf-curling spiders spin webs with a leaf at the center. These spiders have an exoskeleton and eight legs, but no antennae.
Arachnids are a group of animals with similar traits. The following traits can be used to identify arachnids:
They have eight legs.
They have an exoskeleton.
They have no antennae. Observe the animals and read the descriptions.
Scientists sort animals with similar traits into groups. This is called classification. Classification helps scientists learn about how animals live.
How do scientists classify animals? First, they make observations about an animal. Scientists observe the animal's traits, including its body parts and behavior. Then, scientists compare the animal's traits to other animals' traits. Scientists classify animals with similar traits into a group.
To decide if an animal is part of a group, look at the traits of the group.
Arachnids have the following traits:
They have eight legs.
They have an exoskeleton.
They have no antennae.
Compare each animal's traits to the group's traits. Select the animal with traits similar to the group's traits.
A leaf-curling spider has the following traits:
It has eight legs.
It has an exoskeleton.
It has no antennae.
A leaf-curling spider has the traits of an arachnid. A leaf-curling spider is an arachnid.
A white-spotted octopus has the following traits:
It has a soft body.
It has tentacles.
A white-spotted octopus does not have all of the traits of an arachnid. A white-spotted octopus is a mollusk.