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Animals
Animals are multicellular, eukaryotic organisms in the biological kingdom Animalia (). With few exceptions, animals consume organic material, breathe oxygen, have myocytes and are able to move, can reproduce sexually, and grow from a hollow sphere of cells, the blastula, during embryonic development. Animals form a clade, meaning that they arose from a single common ancestor. Over 1.5 million living animal species have been described, of which around 1.05 million are insects, over 85,000 are molluscs, and around 65,000 are vertebrates. It has been estimated there are as many as 7.77 million animal species on Earth. Animal body lengths range from to . They have complex ecologies and interactions with each other and their environments, forming intricate food webs. The scientific study of animals is known as zoology, and the study of animal behaviour is known as ethology. The animal kingdom is divided into five major clades, namely Porifera, Ctenophora, P ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Porifera
Sponges or sea sponges are primarily marine invertebrates of the animal phylum Porifera (; meaning 'pore bearer'), a Basal (phylogenetics) , basal clade and a sister taxon of the Eumetazoa , diploblasts. They are sessility (motility) , sessile filter feeders that are bound to the seabed, and are one of the most ancient members of macrobenthos, with many historical species being important sponge reef , reef-building organisms. Sponges are multicellular organisms consisting of jelly-like mesohyl sandwiched between two thin layers of cell (biology) , cells, and usually have tube-like bodies full of pores and channels that allow water to circulate through them. They have unspecialized cells that can cellular differentiation , transform into other types and that often migrate between the main cell layers and the mesohyl in the process. They do not have complex nervous system , nervous, digestive system , digestive or circulatory systems. Instead, most rely on maintaining a constant ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
