 - Spiders date back to the carboniferous era (360 million years ago) - All spiders can spin silk at all stages of their life, it is
a fibrous protein - There are approximately 40,000 species of known spiders -Mesothelae Anatomy
External Anatomy - Spiders have a hard cuticle or body shell,
called an exoskeleton. - The cuticle covers the cephalothorax and legs and
prevents the spider from losing moisture and drying out.
- Spiders have two body segments. - The
front segment is called the Cephalothorax. The spider’s eyes, mouth fangs,
stomach, brain and the glands that make the poison are on this part of the
body. The legs are connected to this part, as well. - The second part of the body is called
the Abdomen. The back end of the abdomen is where the spinnerets and the silk
producing glands are. - Spiders have 48 knees. Eight legs with six joints on each - The exoskeleton
provides the spider with structural support. - Unlike insects, spiders have no antennae. They do, however, have two appendages near their mouths that are often confused with insect antennas. These structures, called pedipalps, are used by spiders to manipulate their prey while feeding. - Spiders must molt their exoskeleton when they are growing as it does not stretch. Internal Anatomy - Spiders have different types of respiratory systems. Some
have book lungs, some have tubular tracheae, and others have both tracheae and
book lungs. - Book lungs are located by two hairless patches on the underside of the spider's abdomen. Each lung has an open slit for air intact and a stack of leaflet like, blood filled structures called lamellae. As air passes into the spider's body, blood passes through the lamellae is oxygenated. - Spiders have seven leg segments, and their movements are controlled by muscles and by pressure changes in the body's circulatory fluid. Spiders use muscles to retract their legs, but they lack extension muscles. Spiders extend their legs by changes in body-fluid pressure.- Spiders have an open circulatory system. The heart pumps blood through a series of vessels and arteries. Blood seeps between the spider's tissues, collects in little pockets on the underside of the body, and flows back to the heart. -Spiders have a very narrow digestive tract and cannot consume solids, they inject enzymes into their pray and consume them as a liquid Reproduction - The male transfers sperm to the female using specially modified appendages near the mouth, called pedipalps. Because of this, it is easy to tell what sex a spider is: Female spiders have pedipalps which look like short legs, whereas male pedipalps look like "boxing gloves".- Spiders will lay between 2 and 1000 eggs, depending on the species. Almost all female spiders protect their eggs by making a silk ‘bed’ and then covering them with a silk ’blanket’. She then wraps them in more silk to make the egg sac.  Life and Habits - Generally terrestrial, although some species live under water - Some spiders spin webs of their silk to capture prey while others are ambush predators. Funnel Web
Sheet Web Filmy Dome Web
Orb Webs
- Most spiders are very specific to one environment |
