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Arachnids What are Arachnids?.

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Presentation on theme: "Arachnids What are Arachnids?."— Presentation transcript:

1 Arachnids What are Arachnids?

2 Arachnids Arachnids are spiders, scorpions, mites, and ticks. What they all have in common, and what distinguishes them from insects, are four pairs of legs and no antennae.

3 Focusing on Spiders What are Spiders?

4 Spiders are small eight legged creatures that are best known for spinning silk webs.
Fishing Spider Jumping Spider

5 There are more than 30,000 kinds of spiders.
JEWELLED SPIDERS LYNX SPIDERS

6 Golden Silk Orb Weaver Black House Spider

7 Spider Life A spider’s life span ranges from one season to 20 years depending on the type of spider. Spiders can live anywhere they can find food like fields, woods, swamps, caves and deserts. Bullet 2: One kind of spider spends most of its life underwater. Another kind lives near the top of Mount Everest, the world's highest mountain. Some live in houses, barns, and other buildings. Others live on the outside of buildings, on walls, windscreens and corners of doors and windows.

8 Spider Bodies A spider's body has two main parts.
Spiders come in different shapes and sizes. Spiders come in different colors. A spider has no bones and its tough skin serves as a protective outer skeleton. Two main parts: the cephalothorax, which consists of the head joined to the thorax (chest); and the abdomen. Shape : short and fat, long and thin, flat, one looks like a stick Their legs can be short and stubby, or long and thin. Most females are larger and stronger than the males and occasionally they eat males. Colors: grey, brown and black some are colorful, (so small have to look through a microscope to see their color) Bullet 4: Hairs, humps, and spines (bristles of skin) cover the bodies of most spiders.

9 Spider Legs Spiders have four pairs of legs.
When a spider walks, the first and third leg on one side of its body move with the second and fourth leg on the other side Spider legs: Each leg has seven segments. Tip of the last segment has two or three claws. Surrounding the claws is a pad of hairs called the scopula. (what makes the spiders stick to smooth surfaces, walls ceilings)

10 Spider Eyes A spider's eyes are on top and near the front of its head.
Most species have eight eyes, arranged in two rows of four each. Some spiders can see better than others. Opening of slide: Different species have different numbers of eyes and the size and position also varies. Bullet 2: Other kinds have six, four, or two eyes Bullet 3: Hunting spiders have good eyesight at short distances and their eyesight allows them to form images of their prey and mates. Web-building spiders have poor eyesight and their eyes are used for detecting changes in light. Some species of spiders that live in caves or other dark places have no eyes at all

11 Spider Webs Not all spiders spin webs.
Wherever a spider goes, it spins a silk thread behind itself. Spiders use their webs or draglines to catch prey, for shelter, and for a quick get away! More on how spiders spin webs: Spinnerets are short, fingerlike organs with which the spider spins silk. They are attached to the rear of the abdomen. Most kinds of spiders have six spinnerets, but some may have four or two. The tip of a spinneret is called the spinning field and the surface of each spinning field is covered by as many as a hundred spinning tubes. Liquid silk flows through these tubes from silk glands in the spider's abdomen to the outside of its body and the silk then hardens into a thread. Bullet 2: This thread is called a dragline. The dragline is sometimes called the spider's "lifeline" because the animal often uses it to escape from enemies

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14 Spider Food Below the spider's eyes is its mouth opening.
The spider can only eat  some of the solid tissue of its prey by predigesting it. A large tarantula can reduce a mouse to a small pile of hair and bones in about 36 hours by predigestion and sucking. Bullet 2: Around the mouth are various appendages which form a short "straw" through which the spider sucks the body fluid of its victim. The spider sprays digestive juices on the tissue and the powerful juices dissolve the tissue eat flies and mosquitoes which carry diseases, other spiders,  bees butterflies, insects – it depends on the type of spider.

15 Helpful vs. Harmful Spiders
Spiders are helpful to people because they eat harmful insects which destroy crops. A few kinds of spiders are harmful to human beings. Bullet 2: In North America, six kinds of spiders harm people, they are - the Brown Recluse, Sac, Black Widow, Brown Widow, Red-legged Widow and the Varied Widow. Four of the Widow females are known to bite humans. The bites of these six spiders often cause mild reactions. Usually a person irritates a spider several times for it to bite you.

16 Black Widow

17 LYNX SPIDERS Venusta Orchard Spider  SPINED MICARATHENA


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