Arthropods, such as insects, shrimps, spiders, centipedes, crayfish, scorpions and millipedes, are the most diverse group of animals in the world. They can be seen on land, in the air and in the sea and are classified under the phylum Arthropoda. Many arthropods remain undiscovered, and the number of species in the largest arthropod class, insects, is assumed to be in the tens of millions.Know More
Arthropods are invertebrate animals which have a hard skeleton, or exoskeleton, outside of their bodies. The exoskeleton is composed of segments and jointed appendages. Arthropods also have multiple pairs of limbs and bodies. Most arthropods possess these characteristics. They range in size from microscopic insects to large forms that grow up to several meters in size.
Arthropods are considered a major group of disease carriers and transmitters of infectious diseases. The most common are mosquitoes, flies, lice, ticks, fleas and bugs. Many species of arthropods are agricultural and forest pests and are responsible for some of the most devastating plagues and famine in the world. Bees and butterflies, however, greatly contribute to the human food supply through pollination. Bees also produce honey, which is the source of a growing industry and international trade.Learn more about Worms
Freshwater leeches live everywhere in the world except Antarctica, and marine leeches live in all the oceans. Most leeches are found in fresh water, such as streams, rivers, ponds and marshes, but some species thrive in salt water. Some live on land in moist, muddy areas.Full Answer >
Annelids live all over the world in all types of ecosystems, preferring to burrow in soil, sand or sediment both on land and in the ocean. An estimated 17,000 species of annelids are known to exist worldwide.Full Answer >
More than 15,000 species of annelids exist, including earthworms, leeches and polychaetes, which include fireworms, clam worms, lugworms and bristleworms. Earthworms are probably the most commonly known type of annelids; there are more than 2,700 species of earthworms, with the longest species capable of growing up to 22 feet long.Full Answer >
According to Encyclopædia Britannica, flatworms are mostly parasitic, soft-bodied invertebrates that include tape worms, flukes and planarians. Lacking circulatory, respiratory and skeletal systems, flatworms feature unsegmented bodies and spongy connective tissue that provide structure and fill the spaces between organs.Full Answer >