Invertebrates comprise between 95 and 99 percent of all animal species, so any list is bound to be no more than an overview of the group. Invertebrates are divided among eight separate phyla; it is almost impossible to generalize these phyla. Major phyla of invertebrates are Arthropoda, Cnidaria and Porifera.Know More
Arthropoda is the most common and diverse phylum in the animal kingdom. Almost 75 percent of the animal species on Earth are arthropods, including the almost 1 million species of insects. Spiders, scorpions, mites and ticks are all arachnids, which is the other major group of arthropods. Crustaceans are considered arthropods because of their jointed exoskeletons.
Cnidarians are a large, easily defined phylum that is identified by a single cell type unique to its members. All cnidarians have cnida, or stinging cells, and no other animal has them. Cnidaria includes jellyfish, sea anemones and comb jellies, among others.
Poriferans are among the most primitive, in the sense of resembling the common ancestor, of animals. The phylum Porifera includes all sea sponges. Unlike most animals, sponges live out their lives anchored to a single spot on the sea floor. They totally lack organs and other differentiated structures and are so simple they can be broken into their individual cells, left in a dish for several weeks and then reformed into a functioning sponge.Learn more about Zoology
Given that the Earth has experienced no fewer than six mass extinctions over the last 500 million years, the list of species that once lived but have gone extinct over the ages is vast. As of 2014, the Center for Biological Diversity (CBD) reports that Earth is undergoing its sixth mass extinction, and that the rate of species extinctions stands at between 1,000 and 10,000 times the historical norm.Full Answer >
Animals that live on land are called terrestrial animals. Animals such as cows, buffaloes, zebras, giraffes, lions, tigers and foxes are all terrestrial. Terrestrial animals are classified into mammals, reptiles, birds and insects; snakes and lizards are reptiles, while wolves, dogs and cats are mammals.Full Answer >
The Rainforest Action Network indicates that about half of the world's animal species live in the rain forest. Although rainforests cover only about 6 percent of the Earth's surface, they are home to many animal species. However, some species are still unidentified, which makes it difficult to estimate the number of species living in the rain forest, but one scientist places the number between 20 million and 40 million.Full Answer >
Invertebrates make up between 95 and 97 percent of all animal species on Earth. They play a number of hugely important roles in their ecosystems, such as food, pollination and decomposition. Invertebrates are the planet's biggest source of biodiversity and can be found on every level of the food chain.Full Answer >