Hobbies And Interests
General Characteristics
All invertebrates have certain traits in common, although there is a wide variety of species that exist. They do not have a complex skeletal system, which tends to inhibit their growth, but there are a few species of very large invertebrates despite this. Invertebrates can be found in virtually every climate zone on the planet, but the structures of individual species are very specific to their specific environment and they do not adapt well to different climates and locations.
Marine Invertebrates
The variety of marine invertebrates is vast, and includes both salt and freshwater habitats. The Porifera family includes stationary creatures like sponges. The Cnidaria family is made up of animals like jellyfish and coral, with bodies made up of a jellylike substance in layers or tubes. Mobile animals in the Mollusca category, which include squid, crabs and octopi, all have dorsal bodies and specialized nervous systems.
Worms
Worms are divided into two categories in the invertebrate family: Acanthocephala and Annelid. The first group are parasitic worms like tapeworm and flatworms that have a very sophisticated life cycle and use a variety of vertebrates as their hosts. There are about 1,150 different kinds of these worms. The second group is made up of animals like earthworms and leeches, which have segmented bodies and numerous replicated organs.
Arthropods
The arthropod invertebrates are animals with segmented bodies, numerous jointed appendages and exoskeletons. This huge family includes more than a million species of animals and makes up more than 80 percent of animal life on the planet. Arthropods can be found in every ecosystem in the world and includes spiders, insects, crustaceans and centipedes and millipedes. Each of these groups has unique characteristics that set them apart from other arthropods.