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On the other hand, some 1990s analyses also revived the idea that animals' nearest evolutionary relatives are choanoflagellates, single-celled organisms very similar to sponges' choanocytes – which would imply that most Metazoa evolved from very sponge-like ancestors and therefore that sponges may not be monophyletic, as the same sponge-like ...
The circulation of water brings in food particles and sperm, both of which are collected by choanocytes. In addition to the pinacocyte and choanocyte layers, sponges also have a non-living mesohyl layer that is located between the two living layers. Despite being made up of non-living material, the mesohyl contains living cells called archaeocytes.
Some sponges live to great ages; there is evidence of the deep-sea glass sponge Monorhaphis chuni living about 11,000 years. [ 213 ] [ 214 ] While most of the approximately 5,000–10,000 known species feed on bacteria and other food particles in the water, some host photosynthesizing micro-organisms as endosymbionts and these alliances often ...
Many sponge species live long, and as they grow they record the conditions of the environment around them in their skeletons. Scientists have long used sponges along with other proxies — tree ...
All sponges in this class are strictly marine, and, while they are distributed worldwide, most are found in shallow tropical waters. Like nearly all other sponges, they are sedentary filter feeders. All three sponge body plans (asconoid, syconoid, and leuconoid) can be found within the class Calcarea. Typically, calcareous sponges are small ...
About 311 million years ago, in the Late Carboniferous, the order Spongillida split from the marine sponges, and is the only sponges to live in freshwater environments. [8] Some species are brightly colored, with great variety in body shape; the largest species are over 1 m (3.3 ft) across. [ 6 ]
Non-bilaterians include sponges (centre) and corals (background). Sponges are physically very distinct from other animals, and were long thought to have diverged first, representing the oldest animal phylum and forming a sister clade to all other animals. [ 118 ]
Sponges, known scientifically as Porifera, are the oldest metazoans and are used to elucidate the basics of multicellular evolution. [2] These living fossils are ideal for studying the principal features of metazoans, such as extracellular matrix interactions, signal-receptor systems, nervous or sensory systems, and primitive immune systems.