Menu
Home
People
Places
Arts
History
Plants & Animals
Science
Life & Culture
Technology
Reference.org
Sponge
open-in-new
<p>Sponges or sea sponges are primarily <a href="/facts/Marine_invertebrates/Dt72Kb7s">marine invertebrates</a> of the <a href="/facts/Metazoan/4b8J33nd">metazoan</a> <a href="/facts/Phylum/ELT3Jyax">phylum</a> Porifera , a <a href="/facts/Basal_animal/TF5MGzFb">basal animal</a> <a href="/facts/Clade/XefyYmWn">clade</a> and a <a href="/facts/Sister_taxon/pNNuVex4">sister taxon</a> of the <a href="/facts/Eumetazoa/aTu1J8mo">diploblasts</a>. They are <a href="/facts/Sessility_(motility)/f0xV4VV1">sessile</a> <a href="/facts/Filter_feeder/hmVLwWB5">filter feeders</a> that are bound to the <a href="/facts/Seabed/VvxuEWJu">seabed</a>, and are one of the most ancient members of <a href="/facts/Macrobenthos/Ao3qULvB">macrobenthos</a>, with many historical species being important <a href="/facts/Sponge_reef/EBIj4ATy">reef</a>-building organisms. </p><p>Sponges are <a href="/facts/Multicellular_organism/rk8QBF7o">multicellular organisms</a> consisting of jelly-like <a href="/facts/Mesohyl/JMfBVKcd">mesohyl</a> sandwiched between two thin layers of <a href="/facts/Cell_(biology)/bLM9UQvy">cells</a>, and usually have tube-like bodies full of pores and channels that allow water to circulate through them. They have unspecialized cells that can <a href="/facts/Cellular_differentiation/bCVqUG7w">transform into other types</a> and that often migrate between the main cell layers and the mesohyl in the process. They do not have complex <a href="/facts/Nervous_system/CDxRKU2U">nervous</a>, <a href="/facts/Digestive_system/SdpF0sWq">digestive</a> or <a href="/facts/Circulatory_system/WXwudzzc">circulatory systems</a>. Instead, most rely on maintaining a constant water flow through their bodies to obtain food and oxygen and to remove wastes, usually via <a href="/facts/Flagella/nvQRcbgJ">flagella</a> movements of the so-called "<a href="/facts/Collar_cell/KlA8Bp9M">collar cells</a>". </p><p> Sponges are believed to have been the first <a href="/facts/Outgroup_(cladistics)/XnAuxXsV">outgroup</a> to branch off the <a href="/facts/Evolutionary_tree/f5vVEpeY">evolutionary tree</a> from the <a href="/facts/Urmetazoan/vCsrWmdC">last common ancestor of all animals</a>, with fossil evidence of primitive sponges such as <i><a href="/facts/Otavia/Qsq041rK">Otavia</a></i> from as early as the <a href="/facts/Tonian/qkGE6hCf">Tonian</a> <a href="/facts/Geologic_period/6LBR11yQ">period</a> (around 800 <a href="/facts/Million_years_ago/DXcnXuAw">Mya</a>). The branch of <a href="/facts/Zoology/6Kj13mBt">zoology</a> that studies sponges is spongiology.</p>