Today is

By: Ikedi Ani-okoye.

What is an arachnid?

Arachnids

Which include spiders, Scorpions, ticks, and mites, differ from insects essentially in that their bodies are divided into two rather than three segments. Their ancestors were marine, scorpion-like creatures, which flourished during the Silurian Period (435-400 million years ago); some of these were more than 1m ~39in) long. marine species died out about 250 million years ago, but their descendants have been highly successful on land.

The parts of an arachnid

arachnid's body is divided into two parts. The head and thorax are fused together, forming a cephalothorax, or prosoma, which is joined to the abdomen, or opisthosoma. In some, the abdomen is segmented and may have a call-like extension; spiders' abdomens contain silk glands. An arachnid's cephalothorax has six pairs of appendages.

The first pair (chelicerae) may be pincer- or fang-like, and are used mainly for feeding. The second pair (pedipalps) have several functions, including capturing prey and fertilizing the female, and may be leglike or enlarged with terminal claws. The other four pairs are walking legs, althougih the first pair may also carry sensory organs. Gases are exchanged through the trachea or special respiratory organs called book lungs. Close arachnids digest their food outside the body using enzymes, which are pumped into or poured over food. The resulting liquid is then sucked up.

Types of arachnid

Arachnids are a largo and diverse group. They are divided into 11 orders, each of which has characteristic fearures. Sun-spiders, for exanipic, have massive, forward-facing chelicerae. Roipions are recognizable by their long abdominal "tails", bearing stings, their large, claw-like pedipalps. Whip-scorpions also have large pedipalps, but they are not claw-like,-and the long, whip-like tail is without a sting. Perhaps the biggest variation in appearance is seen in the spiders and the mites.

Spiders way front tiny money spiders with turreted, eye-bearing extensions on the cephalothorax to huge, hairy species, known as tarantulas. The huge number of species that make up the mites and ticks vary from gall-foaming Wides, which are probably the smallest arthropcds in the world at less than 0.1mm (under one 28th) long, to blood- feeding ticks, which can be more than 30mm (1%in) long. Some Hsvc blinder or fastened Bodies that allow them to fit inside a human hair follicle or burrow Through skin layers.

Inside an arachnid

The cephdlothorax houses the brain and sensory organs, as well the sucking stomach the venom gland. The abdomen is concerned digestion, gaseous exchange, reproduction and - in spiders pseadoscorpions, and some mites - the production of silk.

Parental care

Many arachnids, including some harvestmen and ticks, show parental care by guarding their eggs from Predators. Scorpions, whip-spiders, whip-scorpions, and some spiders carry their young around on thieir backs for a while after they emerge from the egg sac or brood chamber:

Spiders' webs

Spiders produce silk to wrap their eggs in, and for lining burrow's and making shelters, bud the most well-known use is capturing prey. knot all spiders catch prey using silk; some simply rely on good eyesight and stealth. Web-making spiders have evolved various ingenious prey-capturing techniques.