Lecture Notes in Invertebrate Zoology

Content Module 1. Introduction. Major Invertebrate Taxa: Sarcomastigophora, Apicomplexa, Microsporidia, Microsporidia.

Lecture Topic 1. Introduction. Major Invertebrate Taxa: Sarcomastigophora, Apicomplexa, Microsporidia, Microsporidia

Zoology as a system of biological knowledge about animals. The history of zoology from Aristotle to the present day. The Significance of the works of C. Linnaeus, J.-B. Lamarck, and C. Darwin in animal Classification. Artificial and natural systems. Basic principles of modern systematics, taxonomic units, binomial nomenclature of species, and scientific language. The division of the animal world into invertebrates and Chordates. The Role of invertebrates in nature, human life, and The Development of aquaculture. The significance of A. Leeuwenhoek's work in discovering the microworld. Systems of Protozoans. Structure/97.html">Definitions and General characteristics. Comparison of animals and plants at various Levels of biological Organization. CHARACTERISTICS OF THE phylum Sarcodina and Flagellata. Structural Features of Representatives of the Class Sarcodina: rhizopods, heliozoans, and radiolarians. The Diversity of life forms within the Class Flagellata. Pigmented (plant-like) and non-pigmented (animal-like) flagellates. Main representatives of the phylum and their practical significance. The role of flagellates as producers and parasites. Colonial flagellates. The role of foraminiferans and radiolarians in The formation of bottom sediments. Pathogenic amoebae.

Protozoans are distributed globally. They inhabit aquatic environments and soils. They include both free-living and parasitic species. Over 30,000 species have been described to date, though it is believed that the majority of protozoans remain unknown to science. Protozoans play a crucial role in the Formation of the Earth's crust. Aquatic protozoans serve as an essential component in the food web for many hydrobionts, particularly fish larvae. Parasitic species cause dangerous diseases in humans and domestic animals, although some show promise for developing biological pest control Methods. Protozoans are eukaryotic organisms at THE CELLULAR LEVEL of organization, morphologically and physiologically complete. They include unicellular and colonial organisms, multinucleated plasmodia, and multicellular forms. The term "protozoa" does not reflect their complex structure; however, this complexity pertains to intracellular structures rather than the tissue-level systems found in Multicellular Organisms (Metazoa). The size of protozoans ranges from 2 µm to 5 cm (averaging 5–250 µm). The smallest species is the intracellular cattle parasite Babesia bovis, whose size does not exceed 2–2.5 µm. Conversely, colonies of radiolarians can reach up to 25 cm in length. Protozoans exhibit a variety of Symmetry forms, including spherical, radial, and bilateral symmetry. A significant number of protozoans are asymmetrical. The most diverse forms of symmetry occur in planktonic marine radiolarians, which possess a mineral Skeleton that often forms complex, regular geometric shapes. Fast-swimming flagellates and Ciliates possess a specialized type of symmetry known as helical. Like any Introduction/5.html">Eukaryotic Cell, a protozoan cell contains general cellular Organelles such as the membrane, Nucleus, Mitochondria (absent in Microspora and some flagellates), Ribosomes, Endoplasmic reticulum, Golgi apparatus, Lysosomes, etc. However, because a protozoan cell Functions as a complete Organism, it also possesses specific organelles that vary among different protozoan groups. The protozoan cell is enclosed by a membrane, or Plasmalemma, which features the mosaic structure typical of Biomembranes. The cytoplasmic membrane is externally coated with a glycocalyx composed of mucopolysaccharides. This layer is linked to The Cell's signaling system and contains specialized receptor molecules. Through the glycocalyx, Cells can selectively accumulate various substances from the surrounding environment for subsequent uptake. In addition to the glycocalyx, many protozoans form various extracellular surface structures, such as scales, cell walls, or shells (tests). In most protozoans, supportive structures form beneath the membrane to maintain a stable cell shape.

Sarcodines predominantly inhabit marine plankton or benthos, and many representatives of this subphylum are also widespread in freshwater habitats and soils, with a small number being parasitic. Over 10,000 species have been described. The life cycle of sarcodines is dominated by the amoeboid form, which is capable of producing pseudopodia. The number, shape, and Fine Structure of pseudopodia vary among representatives of different taxa. Broad, lobe-like pseudopodia are called lobopodia; thread-like, branched pseudopodia capable of interconnecting (anastomosing) are filopodia; and straight, unbranched pseudopodia containing internal rows of microtubules are axopodia. The subphylum comprises the superclasses Rhizopoda and Actinopoda. In rhizopods, the organelles of locomotion and food capture are lobopodia and filopodia. The superclass Rhizopoda encompasses seven classes, some of which remain poorly studied. True amoebae are predominantly freshwater benthic organisms, occasionally parasitic, bearing lobopodia, most commonly uninucleate, either naked or testate. The class of True Amoebae includes the subclasses Gymnamoebia and Testacealobosea.