Arachnids: Class Arachnida

Life Science - Middle School

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Arachnids are in the Class Arachnida and include spiders, ticks, mites and scorpions. Arachnids are different from insects in that they have two body parts instead of three. The front section is called the cephalothorax and can be compared to the first two segments of insects (head and thorax) fused together. The second body section is the abdomen. Arachnids have no wings and no antennae. They generally have eight legs plus two pairs of smaller pincer-like appendages in the front. The first pair is called the chelicerae and are used for feeling, feeding and sometimes for defense ( fangs). The second pair is called pedipalps and are used for feeding, reproduction and sometimes as extra legs. Most arachnids are insect predators which can benefit human habitats, but some are parasites like ticks, chiggers and mites. Most arachnids live on land. They bite or sting and some are venomous. Some arachnids build elaborate webs. The Class Arachnida is broken down into many groups called Orders. The true spiders (Araneae) are the largest Order and include some common spiders like the tarantula (1), black widow (2), house spider (3), jumping spider (4) and brown recluse (5). Another Order (Opiliones) has the daddy long legs (6), also known as harvesters. Ticks (7) and mites are in their own Order (Acarina), as are the scorpions (8) (Order - Scorpiones). Arachnids - Class Arachnida Araneae True Spiders Acarina Mites and Ticks Scorpiones Scorpions Opiliones Daddy Long Legs chelicerae pedipalps abdomen cephalothorax eight legs 4 1 3 5 8 6 7 2
94-4028 Arachnids - Class Arachnida Arachnids are different from insects in that they have __________ body parts instead of three. The front section is called the cephalothorax and can be compared to the first two segments of insects (head and thorax) fused together. The second body section is the __________________________________. Arachnids have no wings and no antennae. They generally have ________________ legs plus two pairs of smaller pincer-like appendages in the front. Most arachnids are ______________________ predators which can benefit human habitats, but some are parasites like ticks, chiggers and mites. Most arachnids live on ______________. They bite or sting and some are venomous. Some build elaborate ______________. The true spiders are the largest Order and include some common spiders like the ____________________________ (1), _______________________________________ (2), _______________________________________ (3), _______________________________________ (4) and _______________________________________ (5). Another Order has the _______________________________________ (6) also known as harvesters. ________________ (7) and mites are in their own Order, as are the ___________________________ (8). Araneae True Spiders Acarina Mites and Ticks Scorpiones Scorpions Opiliones Daddy Long Legs eight legs 4 1 3 5 8 6 7 2