Invertebrates: General Characteristics and Classification PDF

Invertbratse A.T.Ranem mohammed General characteristics of inertebrates 1. Single-celled animals, some of which are colonial, live in aquatic environments.or on land 2. most of it is microscopic. 3. There are no organs or tissues, but there are speciali...

Invertbratse A.T.Ranem mohammed General characteristics of inertebrates 1. Single-celled animals, some of which are colonial, live in aquatic environments.or on land 2. most of it is microscopic. 3. There are no organs or tissues, but there are specialized organelles. 4. Free living ,symbiotic,mutualistic, commensalistic, ,parasiric 5. Movement is achieved by pseudopodia, flagella, or cilia. 6. Some are equipped with a simple internal or external structure, but some of them are naked 7. Its nutrition can be either autotrophic, heterotrophic, or saprozoic. 8. It reproduces asexually by fission or budding, and sexually by conjugation or syngamy. The organisms that do not possess a skeleton or a backbone are called )invertebrates( Invertebrates are characterized by having an external skeleton, a dorsally located heart, and a ventrally located nerve cord Invertebrates include all organisms ranging from single-celled organisms to echinoderms, and they exhibit diverse characteristics nvertebrates have significant importance, including:  Their use in biological control.  Many of them are considered good food for fish, such as shrimp and shellfish.  They help in pollinating plants, like insects  Some of them have the ability to produce beneficial substances for humans, such as bees and silkworms The harms of invertebrates include:  Some of them cause diseases in humans, such as the malaria parasite and tapeworms and roundworms  Some of them accumulate on the surfaces of ships, causing damage.  Some of them serve as disease vectors, such as mosquitoes There are several classifications of invertebrates, most of which belong to the kingdom Protista, while some consider them a single phylum, the Invertbratse A.T.Ranem mohammed protozoa, because they consist of a single cell. Others divide them into four phyla: mastigophra ,sarcodina ,sporozoa,ciliata Classification of protozoa The nucleus is surrounded by a membrane that connects its internal components to the cytoplasm through small pores. It contains genetic material (DNA) on chromosomes within the nucleus. There is also one or more nucleoli within the nucleus. The central areas of the cytoplasm can sometimes be distinguished as ectoplasm and endoplasm. The endoplasm appears more granular and contains the nucleus and cytoplasmic organelles, while the ectoplasm appears more transparent under the light microscope and contains the bases of cilia and flagella. It is often more solid. The primary means of movement for protozoa are cilia, flagella, and pseudopodia Cilia are composed of( 2-9)microtubules called the axoneme. It is covered by a membrane that is continuous with the cell membrane that surrounds the rest of the organism Pseudopodia It refers to temporary or semi-permanent extensions or protrusions of protoplasm that appear especially in the class of amoebas The pseudopodia are classified into four types based on their structure and shapes: A. Lobopodia B. Filopodia C. Rhizopodia D. Axopodia Invertbratse A.T.Ranem mohammed FEEDING Protozoa can be classified into autotrophic FEEDING and heterotrophic FEEDING based on their ability to synthesize their organic components from inorganic materials or their necessity to obtain organic molecules produced by other organisms. Food Vacuoles The food vacuole is located in the cytoplasm and contains food particles along with a small amount of liquid or the aqueous medium surrounding the protozoan. In most flagellates and amoebas, the food vacuoles take on the shape of the food particles contained within them In ciliates, the food particles are usually small, so the vacuoles in this case are typically spherical. TYPE OF FEEDING IN PROTOZOA 1. Holozoic When complex organic materials are engulfed or ingested into the organism, they are surrounded by a membrane, forming a food vacuole that moves within the endoplasm. Enzymes are added to this vacuole, and digestion occurs, after which the beneficial nutrients are absorbed. Invertbratse A.T.Ranem mohammed 2. Autotrophic or Holophytic The organisms that contain chlorophyll inside them produce their own food through the process of photosynthesis. 3. Saprozoic The saprophytic FEEDING occurs through cellular drinking (pinocytosis) or by the direct transfer of dissolved substances. This transfer can occur directly across the cell membrane via diffusion, facilitated transport, or active transport. 4. Mixotrophic It can feed in more than one way as mentioned above, depending on the surrounding environment. For example, Euglena can feed saprophytically, but at the same time, it has the ability to produce its own food Respiration (BREATHING) 1. Aerobic 2. Anaerobic Excretion he removal of water-soluble metabolic waste products occurs through diffusion across the cell membrane, and it may also be expelled via contractile vacuoles. As for insoluble substances, they are expelled through food vacuoles via the cell membrane and through a temporary outlet known as the cytopyge.