Search results
Results from the WOW.Com Content Network
However, cephalopods also have cells called iridophores, thin, layered protein cells that reflect light in ways that can produce colors chromatophores cannot. [45] The mechanism of iridophore control is unknown, but chromatophores are under the control of neural pathways, allowing the cephalopod to coordinate elaborate displays.
Diagram of a cephalopod's photophore, in vertical section. A photophore is a glandular organ that appears as luminous spots on marine animals, including fish and cephalopods. The organ can be simple, or as complex as the human eye, equipped with lenses, shutters, color filters, and reflectors; unlike an eye, however, it is optimized to produce ...
Diagram of ammonite soft tissue anatomy based on other cephalopods along with a cross section (right). Note that shape and length of tentacles are speculative. Although ammonites do occur in exceptional lagerstatten such as the Solnhofen Limestone, their soft-part record is surprisingly sparse. Beyond a tentative ink sac and possible digestive ...
Structure of a plant cell. Plant cells are the cells present in green plants, photosynthetic eukaryotes of the kingdom Plantae.Their distinctive features include primary cell walls containing cellulose, hemicelluloses and pectin, the presence of plastids with the capability to perform photosynthesis and store starch, a large vacuole that regulates turgor pressure, the absence of flagella or ...
Photosystems are found in the thylakoid membranes of plants, algae, and cyanobacteria. These membranes are located inside the chloroplasts of plants and algae, and in the cytoplasmic membrane of photosynthetic bacteria. There are two kinds of photosystems: PSI and PSII.
The hyponome or siphon is the organ used by cephalopods to expel water, a function that produces a locomotive force. The hyponome developed from the foot of the molluscan ancestor. [14] Water enters the mantle cavity around the sides of the funnel, and subsequent contraction of the hyponome expands and then contracts, expelling a jet of water.
The cephalopods were once thought to have evolved from a monoplacophoran-like ancestor [8] with a curved, tapering shell, [9] and to be closely related to the gastropods (snails). [10] The similarity of the early shelled cephalopod Plectronoceras to some gastropods was used to support this view.
The eyeballs were likely thicker, stronger, and more convex than in other cephalopods. [11] The mantle cavity of cephalopods serves to contain the gills, gonads, and other organs; also, water is siphoned into and expelled out of the mantle cavity via a tube opening near the arms of the animal, the hyponome, for jet propulsion.