Phylum Arthropoda (Arthropods)

Arthropods includes insects, arachnids, and crustaceans.


Body Structure


1235.jpg One part of the structure is the exoskeleton This provides support and protection in some invertebrate animals. It consists of proteins and chitin. They also have legs that are jointed. They usually have several legs. Some have 6, some have 8, and some even have 10. These include dragonflies and most insects such as butterflies. Their jointed legs are also fairly weak. They also have jointed limbs.They cannot bend because of their hard skeleton. Arthropods that live in water use gills to breathe. Some arthropods have tracheal air systems. These are air sacs leading into the body from pores called spiracles. Arthropods have an open circulatory system. This is an arrangement of transport inside the bodies of many mollusks and arthropods.

Obtaining Food


Some crustaceans obtain food by eating dead, decayed, or rotten plants and animals. They eat the remains of other predators prey. Other crustaceans like the pistol shrimp stun their prey and then eat it from their. Arthropods may even eat on parasitic animals too.



Reproduction


Most arthropods have male and females. Sperm are usually passed to the female in a sealed package called a spermatophore. Newly hatched juveniles are smaller than and often different from the parents in form, food, and habits. These juveniles become adults through metamorphosis. When they grow, they also molt out there exoskeleton.



Movement


There are different movements for different Arthropodas; some crawl, some fly, some slither, and some spin webs to move. Since exocuticle is absent from joints, arthropods can move appendages and flex one body segment on another. Arthropods movement is achieved by muscles attached in the skeleton. Most arthropods use their appendages for movement, for example, as paddles in aquatic species or as legs in terrestrial ones.

Adaptations


Arthropods have many adaptations that allow it to survive in their environment. The first adaptation is that the arthropods have an outer body covering called and exoskeleton. The exoskeleton is made of a special material called chitin. This material is hard and thick so it protects it from predators. It also helps the arthropods in the desert not to dry out. The exoskeleton also gives it support and connects joints and muscles inside the body. In other arthropods like shrimp, the exoskeleton works with the muscles to give it a locomotive force. Another adaptation arthropods have is that they have special mouth parts. A mosquito ( arthropod ) has a special mouth which allows it to break through humans skin and suck our blood. Other arthropods use there mouth for many different things like taking down prey and more. The next adaptation arthropods have are their jointed legs. These jointed legs help them so much. With them they can move really fast because their legs are flexible, or jointed, so they can get away from prey or catch prey. This adaptation really helps the arthropods survive. Another adaptation arthropods contain is that they have compound eyes. All arthropods including houseflies and mosquitoes have compound eyes. Instead of having one lens in each eye, arthropods have several lenses in each eye. These lenses give them a very wide angle of vision. They can pretty much see all the way behind them. All though they have this great vision they can’t see far distances. Their compound eyes actually help them detect movement. This helps them because they can be aware of prey and escape. The last adaptation arthropods have is that they have segmented bodies. These segmented bodies help them curl up into small spaces and move faster. This is helpful because it when they are getting chased by prey the arthropods can crawl into small spaces that their predators can’t reach. Also, the segments help their body to move more smoothly. These are all the adaptations arthropods contain. Some other things that arthropods can do like the snake is protect itself from predators. Things that the crocodiles can do is protect itself by going on land and sea.



Importance to Humans

Arthropods are some of the world most popular seafood including lobster, crab, and shrimp. These animals are all crustaceans. Honey, wax, and silk also are produced my insects. Even though we do love those arthropods others may not be as tasty as the crustaceans. All insects and arachnids are arthropods. Bees are in the insect category that is in the arthropod category. Bees pollinate flowers and the plant then reproduces and creates more plants that give humans oxygen through photosynthesis. Arthropods also play a big key on human disease like the West Nile virus and all viruses given by insects.


SubPhylums


giicrab.jpgCrustacea

They are a large group of arthropods. There are about 42,000 species of crustacean. Most of them live in fresh water or marine environments. The Crustacea can be divided into six major groups. Carcinology is the scientific study of crustaceans. A carcinologist is a scientist who works in carcinology. Many crustaceans are consumed by humans.
The head has 2 pairs of antennas, a pair of compound eyes, 2 mandibles and 2 pairs of maxillae. Appendages are biramous, and adapted for filter feeding, respiration, swimming, burrowing, brooding young and mating. The subphylum includes water fleas, copepods, barnacles, crabs, lobsters, crayfish, shrimps, etc.

Picture_2.pngMyriapoda

The myriapoda or "many-legged ones" includes millipedes, centipedes, and many others. The Myriada mosty lives in moist forests, grasslands, and deserts. Theses arthopods are all herbivores except for the centipedes. THere are four groups of myriapods. These four groups are The Symphyla, Pasuroda, Chilopoda, and Diplopoda. Some Myriapoda have a mandible that is either used for biting, cutting or holding.


Classes


grasshopper.gifInsecta

Insects are a major group of arthropods. Insects may be found in all different environments on the planet. Not that many can be found in the ocean. Crustaceans will kick them out. There are approximately 5,000 dragonfly species, 2,000 praying mantis, 20,000 grasshopper, 170,000 butterfly and moth, 120,000 fly, 82,000 true bug, 360,000 beetle, and 110,000 bee and wasp species to date. Estimates of the total number of current species range from two million to fifty million.


Picture_7.pngArachnida

They are a class of joint-legged invertebrate animals. Arachnidia comes from the Greek word spider. Arachnida has 4 pairs of legs. Arachnids can be distinguished by the fact they have no wings and no antennas. They are mostly carnivorous. They usually lay eggs. They have 2 kinds of eyes.



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