International Journal of Pure and Applied Zoology

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Opinion Article - International Journal of Pure and Applied Zoology (2023) Volume 11, Issue 1


James Shapiro*

Department of Biology, University of California, Santa Cruz, United States

Corresponding Author:
James Shapiro
Department of Biology
University of California, Santa Cruz
United States

Received: 30-Dec-2022, Manuscript No. IJPAZ-23-85931; Editor assigned: 02-Jan-2023, PreQC No. IJPAZ-23-85931(PQ); Reviewed: 16-Jan-2023, QC No. IJPAZ-23-85931; Revised: 18-Jan-2023, Manuscript No. IJPAZ-23-85931(R); Published: 25-Jan-2023, DOI: 10.35841/2320-9585-11.1.164

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Acorn worms are a hemichordate class of invertebrates that includes one order of the same name. Hemichordata is a phylum of triploblastic, enterocoelomate, and bilaterally symmetrical marine deuterostome organisms that is commonly regarded as the echinoderms' sister group, acorn worms are solitary wormlike creatures. They are generally burrow dwellers and deposit feeders, however some species are pharyngeal filter feeders, and the Torquaratoridae family are free-living detritivores. Many are well known for producing and accumulating halogenated phenols and pyrroles. Acorn worms have a worm-like body with an anterior proboscis, an intermediate collar, and a posterior trunk. The proboscis is a ciliated and muscular organ that aids in movement as well as the collecting and transport of food particles, the mouth is located between the proboscis and the collar.

Acorn worms are solitary worm-like creatures. They are burrow-dwelling deposit feeders, although some species are pharyngeal filter feeders, and the Torquaratoridae family are free-living detritivores. Many are well known for generating and accumulating halogenated pyrroles and phenols. Pterobranchs appear to be filter feeders that reside in a coenecium, which is a collagenous tube structure [1]. Acorn worms have three components to their body, an anterior proboscis, a middle collar, and a posterior trunk. The proboscis is a muscular, ciliated organ that assists animals in movement as well as gathering and transferring food particles [2]. The hemichordates, along with the Echinoderms, compose the Ambulacraria, the chordates' closest living evolutionary relatives. As a result, these sea worms are of significant importance in the study of chordate development. There are various hemichordate species, each with a moderately diverse embryological development. Hemichordates are known to evolve in two ways: directly and indirectly.

The lateral cilia that line the gill slits form a water circulation that enters from the mouth, moves through the buccal cavity, gill slits, pharynx, and branchial sacs, and leaves through the gill pores [3]. The excretory organ is the glomerulus or proboscis gland, which is positioned in front of the central sinus and projects into the proboscis coelom. Particles of brown or yellow colour are discharged. The nervous system is primitive, as seen in coelenterates and echinoderms. Because the sexes are dioecious, males and females live in separate tubes. External fertilisation occurs when gametes are shed into seawater and mix there. Tornaria larvae are planktonic ciliated larvae that develop in an indirect manner [4]. A dorsal, hollow nerve cord, a notochord, pharyngeal gill slits or pouches, and a coelom, the fluid-filled primary body cavity, distinguish the phylum Chordata. Acorn worms feature pharyngeal gill slits, a nerve cord, and a coelom, which makes them similar to chordates. A little structure in the anterior trunk was formerly assumed to be a notochord, but it has since been revealed to be an extension of the gut. The female lays a huge number of eggs trapped in a gelatinous mass of mucus, which are then externally fertilised by the male before being broken up and dispersed by water currents.

The skin is coated with cilia and mucus-secreting glands. Some species create a bromide molecule that has a therapeutic odour and may protect them from bacteria and predators. Acorn worms move slowly, relying on ciliary activity and proboscis peristalsis [5]. Debris feeders, acorn worms chew sand or mud and extract organic detritus. Others feed on organic material suspended in water that they may drag into their mouth with the cilia on their gill bars. Acorn worms have an open circulatory system in which blood flows through sinuses in the tissues. A dorsal blood artery in the mesentery above the gut transports blood to a sinus in the proboscis containing a muscular sac that functions as a heart. Unlike most other species' hearts, this organ is a closed fluid-filled vesicle with no direct connection to the blood system. Nonetheless, it pulsates on a regular basis, assisting in the passage of blood through the surrounding sinuses, sucking oxygenated water into their mouths, acorn worms breathe. The water subsequently comes out of the animal's trunk-mounted gills. As a result, the acorn worm breathes similarly to fish.


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