Sponges can contract specific body parts, such as to close their osculum (see above image), and their entire bodies, dramatically shrinking their size in the process, in response to certain stimuli. General body structure of a sponge and the cells that make up the ‘body’. These do not include nerve cells, yet many species appear to overcome this limitation and perform behaviours only achievable through cell to cell coordination. mouth, muscles, heart), instead functioning through the individual actions of specialised cell types. Water flows in through the pores, where specialised feeding cells, choanocytes, filter out particles of food, and then back out through a collective opening, the osculum, along with any waste. Sponges, so called for the pores around their bodies, consist of two cell layers with a middle gelatinous layer which may contain ‘loose’ cells and pieces of carbonate, spongin (protein fibres), or silica (glass), depending on the class of sponge, for structural support. A collection of sponges with the yellow tube sponge (Aplysina fistularis) taking centre stage. Some animals groups achieve coordinated movements with very simple nervous systems, but one group, the sponges (Porifera) has no ‘true’ nervous system at all. Most animals achieve this through a system of nerves, which transmit information as electrical signals, and a ‘central processor’ (e.g. For any multicellular organism many of these movements need to be coordinated to benefit the organism. The ability to move through one’s environment is key the existence of virtually all life on earth.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |