Bryozoa（Bryozoa）A phylum of the animal kingdomEucoeloma。Because the anal opening is outside the tentacle crownExternal anal phylumIt is called.About 20000 species have been described, of which about 1/5 are living species.
Bryozoa is a group that lives in a fixed way and looks like mosses, so it is named.Most live in temperate waters, and a few are freshwater.Each individual of the group is very small, less than 1mm.A horny or calcareous chamber secreted by the ectoderm;The head of the individual is not obvious, and the front body wall protrudes outward, forming a round or horseshoe shaped object around the mouth, on which there are tentacles with cilia. This is the tentacle crown, called the total pole, and it is a feeding organ.The anal opening is on the outside of the total load, so it is called Ectoprocta, an external anal animal.Hermaphrodite, usually withBudding reproduction。There are about 4000 existing species and 15000 fossil species.It can be divided into 2 classes: Perilabia and Nulabia.Marine bryozoans form specific biological communities on the bottom of ships and some facilities, causing varying degrees of harm, hindering the growth and development of cultured organisms, and reducing production
Habitat environment
Announce
edit
Most bryozoans live in the sea.Most of them live in the shallow sea of the continental shelf.Generally, they are fixed on the hard attachment foundation, and a few species are fixed in the sediment by attachment mechanism.Feeding on suspended substances in water.
Bryozoa feed on suspended solids in water.When the tentacle crown extends out of the body, the tentacle extends into the tentacle clock. Water containing food particles enters the tentacle clock from the upper part of the tentacle crown, then gathers in the upper part of the mouth, enters the elastic pharynx, and inhales into the stomach by the sudden expansion of the pharynx.
economic significance
Announce
edit
The calcareous skeleton of bryozoans is quite solid, and their fossils are of certain value in stratigraphic correlation analysis.Some species of living marine bryozoans living in intertidal and subtidal zones are one of the main components of fouling community.They are attached to the bottom of the ship, buoys, cables and other underwater facilities;Some species compete with cultured shellfish and algae for attachment base, affecting seedling collection and aquaculture production;Some fresh water and marine products often block water supply and drainage pipelines.
BryozoaBrachiopodaandBroomhophyllaAnimals are between protozoa and hind mouth animals. Studying their classification, morphology, function and evolution is helpful to clarifyinvertebratePhylogeny of groups.
structure
Announce
edit
The bryozoan group is the primary insect or individual insect formed by attachment and metamorphosis of the larva generated by sexual reproduction through asexual budding or germination of some dormant bud.According to the growth mode, it can be divided into two major categories: upright type and coated type. Most bryozoa belong to the latter category.These groups lie flat on various substrates, most of which are simple in shape, thin and crusty, most of which are single layers.Double or multi-layer groups have more diverse shapes.The vertical population has a large degree of freedom of growth, and the population shape is complex. The common shapes are block, network, chain, fan, branch, and bush.There is a common phenomenon of similarity in bryozoan groups, that is, the same group type (such as reticular group and branching group) can occur in parallel in different species, genera, even families and orders.Bryozoans have a high adaptability to living environment. Even the same species will change their population morphology due to different environmental conditions.
The body wall of each worm consists of epidermis, epithelium and peritoneal membrane.Epidermis is secreted by epithelium, chitin or colloid, or calcified into hard exoskeleton.
The tentacle crown, digestive tube and associated muscles are the main components of an insect, which are collectively called the insect body.The insect structures of various bryozoans are generally similar, usually pear shaped or bottle shaped.The digestive tube is curved into a "U" shape and consists of mouth, pharynx, stomach, rectum and anus.The anus is very close to the mouth due to the bending of the digestive tube, but the opening is outside the tentacle crown.The tentacle crown is the feeding organ of bryozoans. When feeding, the tentacle crown protrudes out of the body with the help of body wall deformation.
Bryozoans have neither respiratory, circulatory and excretory systems, nor vision andorgan of hearing。The only central mechanism controlling the activity of the worm is the spherical ganglion located at the top of the worm, between the mouth and the anus.
The bryozoan population is hermaphrodite, and most individual insects are also hermaphrodite.The testis is located on the stomach, and the ovary is usually on the body wall of the worm.The testis and ovary have no ducts. The germ cells enter the body cavity and escape from the body cavity.
BryozoanIt is a kind of aquatic community animals.In the early 1930s, these animals were namedSwarm（Polyzoa Thompson, 1930) andBryozoan（Bryozoa Ehrenberg，1931）。Although the latter name is later, the priority law is not strictly implemented in the names of taxa above family level, and most countries, especiallyEuropeMainland andU.S.AIt has been widely used by scholars for a long time.Most bryozoans live inOrdovicianTo the modern normal sea water, the benthic life is fixed.At present, there are at least 1300 genera, 15000 fossil species and 4000 living species.It belongs to microfossils and has certain ecological and stratigraphic significance.
Bryozoa should be associated withbryophyteIs different.
bryophyteBelongs to the plant kingdom,Bryophyta, usually divided into liverwort（Hepati-cae）And mosses（Musci）In recent years, many scholars have advocated thathornwort It is divided from the class of liverwort and is divided into the class of hornwort（Anthocerotae）, in parallel with bryozoa and mosses.There are about 23000 species in the world and about 2100 species in China.
Mosses do not have real roots, generally only have short stems and small thin leaves, and there is no conducting tissue in the stems and leaves. Most of them grow in damp environments, such as under forest soil surface, tree branches,swampThe belt, the water stream, the shady corner, etc., especially in the forest area, grow luxuriantly and often gather together into a piece.[1]
