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While also known as the "boring sponge", Cliona celata is the only species of sponge without microscleres. [citation needed] Cliona celata is a distinctive sponge known for its unique morphology and characteristics. In its 'raphyrus' or massive stage, it forms large lobose structures with rounded ridges, reaching sizes of up to 40 cm across and ...
Demosponges (Demospongiae) are the most diverse class in the phylum Porifera. They include greater than 90% of all species of sponges with nearly 8,800 species worldwide (World Porifera Database). [5] They are sponges with a soft body that covers a hard, often massive skeleton made of calcium carbonate, either aragonite or calcite [citation ...
Cultural economics is the branch of economics that studies the relation of culture to economic outcomes. Here, 'culture' is defined by shared beliefs and preferences of respective groups. Programmatic issues include whether and how much culture matters as to economic outcomes and what its relation is to institutions. [1]
Social scientists such as V. Gordon Childe have named a number of traits that distinguish a civilization from other kinds of society. [24] [25] Civilizations have been distinguished by their means of subsistence, types of livelihood, settlement patterns, forms of government, social stratification, economic systems, literacy and other cultural ...
The earliest known hexactinellids are from the earliest Cambrian or late Neoproterozoic eras; Helicolocellus is a possible hexactinellid relative from the late Ediacaran. [23] They are fairly common relative to demosponges as fossils, but this is thought to be, at least in part, because their spicules are sturdier than spongin and fossilize better.
The history of life on Earth traces the processes by which living and extinct organisms evolved, from the earliest emergence of life to the present day. Earth formed about 4.5 billion years ago (abbreviated as Ga, for gigaannum) and evidence suggests that life emerged prior to 3.7 Ga. [1] [2] [3] The similarities among all known present-day species indicate that they have diverged through the ...
A life history strategy is the "age- and stage-specific patterns" [2] and timing of events that make up an organism's life, such as birth, weaning, maturation, death, etc. [3] These events, notably juvenile development, age of sexual maturity, first reproduction, number of offspring and level of parental investment, senescence and death, depend ...
Little is known regarding their reproduction habits, however fluid dynamics of their body structure likely influence reproduction and it is hypothesized that they may be hermaphroditic. [ 4 ] Collected specimen of Euplectella aspergillum