what are the basic anatomy of a brachiopod.
All brachiopods are suspension feeders, and extract food from the water around them using a structure known as a lophophore. The soft tissues of a brachiopod are enclosed by two valves, which can be opened and closed by muscles. All are sessile, and most are attached permanently to the substrate via a fleshy appendage known as a pedicle. Brachiopods superficially resemble bivalves, which are much more common today. Both are suspension feeders and possess shells composed of two valves. The two taxa are however, anatomically very different. Bivalves use a muscle to close their shells and an elastic ligament to open them again. A brachiopod uses muscles to both open and close the shell. Another way of telling the two apart is by a quick inspection of the two valves. In a brachiopod, the valves are different sizes, whereas the valves of a bivalve are usually identical to one another; mirror images. In the bivalves, the line of symmetry runs between the two valves. Also unique to the brachiopods is the lophophore, an organ utilised in both feeding and respiration.
The picture above outlines the main internal morphological features of a brachiopod. The brachiopod featured is Magellania, an articulate brachiopod. Nevertheless, the basic features remain the same. The brachiopod remains attached to the substrate via the stalk-like pedicle. The pedicle valve, ventral in this species, is the valve from which the pedicle exits. The adductor and diductor muscles work to close and open the valves respectively. The lophopore, not indicated in this diagram, is supported by the brachium. Many fossil brachiopods had a calcified support structure for the lophophore. In extant brachiopods, the lophophore is supported purely by hydrostatic pressure. Water is drawn into the valve and food particles are filtered out by the lophophore.
External brachiopod morphology, by Muriel Gottrop.
The above drawing illustrates some of the external features of a brachiopod shell, showing the line of symmetry and the dissimilarity between the two valves. As already mentioned, the line of symmetry in bivalves runs between the two valves.
If you had provided the link to that answer, which is
http://palaeo.gly.bris.ac.uk/Palaeofiles/Fossilgroups/Inarticulate/Characters%20and%20Anatomy.html ,
the figures would also be visible.
The basic anatomy of a brachiopod consists of several key features:
1. Shell: Brachiopods have a bivalve shell, meaning it is composed of two halves, known as valves, that are hinged together. The shell is made of calcium carbonate and provides protection for the animal's soft tissues.
2. Pedicle: Brachiopods have a muscular stalk called a pedicle, which allows them to attach themselves to the substrate (such as rocks or the ocean floor).
3. Lophophore: Inside the shell, a brachiopod has a lophophore, which is a specialized feeding organ. It consists of a circle of tentacles that surround the mouth and are used for filter-feeding.
4. Mantle: The mantle is a thin layer of tissue that lines the inner surface of the brachiopod's shell. It secretes the shell and also helps with respiration and excretion.
5. Digestive System: Brachiopods have a complete digestive system, with a mouth, stomach, and intestine. They consume microscopic organisms and organic particles from the water using their lophophore.
6. Nervous System: Brachiopods possess a simple nervous system with a nerve ring around the mouth area and several pairs of nerve cords that extend along the body.
Understanding the basic anatomy of a brachiopod requires studying their external and internal structures. You can find detailed diagrams and descriptions in biology textbooks, zoology references, or online resources focused on invertebrate anatomy. Additionally, scientific articles and research papers on brachiopods may provide more detailed information about their anatomy and internal systems.