Spider belongs to which of the following classes in the phylum arthropoda?

1. Analyze the question You are asked to identify the class of Arthropoda that spiders belong to.

2. Explain the concept Phylum Arthropoda is divided into classes based on body structure, number of legs, and appendages:

| Class | Examples | Key features | |---|---|---| | Insecta | Grasshopper, housefly, butterfly | 3 body parts (head, thorax, abdomen), 6 legs, antennae, usually wings | | Arachnida | Spider, scorpion, tick, mite | 2 body parts (cephalothorax and abdomen), 8 legs, no antennae, no wings | | Crustacea | Crab, prawn, lobster | 2 pairs of antennae, usually 10 legs, mostly aquatic | | Chilopoda | Centipede | Flattened body, 1 pair of legs per segment | | Diplopoda | Millipede | Cylindrical body, 2 pairs of legs per segment |

(Chilopoda and Diplopoda are together called Myriapoda.)

3. Solution

• A spider has 8 legs, which rules out Insecta (6 legs).
• Its body has two parts: a cephalothorax and an abdomen.
• It has no antennae and no wings, which rules out Insecta and Crustacea.
• It does not have a long body with many segments each bearing legs, which rules out Chilopoda and Myriapoda.

These are the features of class Arachnida.

4. Answer A. Arachnida

5. Exam tip Remember: "Arachnida = 8 legs". Think of Arachne, the spinner in Greek myth who was turned into a spider. Whenever you see spider, scorpion, tick, or mite in a question, think Arachnida.