STRUCTURE AND FUNCTIONS OF INVERTEBRATES

Introduction CORAL REEFS AND THEIR TYPES: Coral reefs are some of the most diverse and vibrant ecosystems on the planet. Often referred to as the "rainforests of the sea," they provide essential habitats for a wide array of marine life, including fish, invertebrates, and other marine organisms. Beyond their biodiversity,…

Introduction METAGENESIS IN CNIDARIANS: Metagenesis, also known as the alternation of generations, is a biological process in which an organism alternates between two distinct forms during its lifecycle. This phenomenon is particularly common in certain groups of invertebrates, including cnidarians, a diverse group of animals that includes jellyfish, corals, and…

Introduction ANATOMY AND PHYSIOLOGY OF JELLYFISH: Jellyfish are captivating and ancient marine animals that have been around for over 500 million years. Despite their simplicity, they exhibit remarkable adaptations that allow them to thrive in various marine environments. Known for their gelatinous bodies and mesmerizing movement, jellyfish are members of…

Introduction Anatomy and Physiology of Ascaris lumbricoides: Ascaris lumbricoides is one of the most well-known parasitic nematodes (roundworms) that infects humans. It is responsible for the disease known as ascariasis, which affects millions of people worldwide, particularly in regions with poor sanitation. To understand how this parasite works, it is…

Introduction ANATOMY AND PHYSIOLOGY OF LEECHES: Leeches are a fascinating group of segmented worms belonging to the class Hirudinea within the phylum Annelida. These organisms are known for their specialized adaptations and unique lifestyle, ranging from freshwater species to parasitic forms found in a variety of hosts. Although they are…

Introduction Invertebrate taxonomy is a crucial subdiscipline within the field of zoology that focuses on the classification and identification of invertebrate animals—those without a backbone. As the largest group of animals on Earth, invertebrates make up approximately 95% of all known animal species. These organisms range from microscopic entities like…

Introduction DISEASES CAUSED BY HELMINTHS: Helminths are parasitic worms that cause a range of diseases in humans. These worms are multicellular organisms, and they belong to various classifications such as nematodes (roundworms), cestodes (tapeworms), and trematodes (flukes). Helminthic infections are common in tropical and subtropical regions, especially where sanitation is…

INTRODUCTION Filariasis and its vector: Filariasis is a serious parasitic disease that affects millions of people worldwide, especially in tropical and subtropical regions. The disease is caused by thread-like worms that live in the lymphatic system, leading to a condition known as lymphatic filariasis. It is primarily transmitted through the…

INTRODUCTION Screenshot The circulatory system of amphibians, a class of vertebrates that includes frogs, toads, salamanders, and newts, is adapted for their unique dual life in both aquatic and terrestrial environments. This system ensures efficient transport of oxygen, nutrients, and waste products throughout their bodies, allowing them to thrive in…

Introduction Fish culture, commonly known as fish farming or aquaculture, is a practice as old as human civilization itself. Today, it stands at the forefront of efforts to meet the world's growing demand for seafood while conserving our natural fisheries. In this comprehensive exploration, we dive into the fascinating world…

INTRODUCTION Nutrition in Protozoa involves various modes of feeding. Protozoa are a diverse group of single-celled eukaryotic microorganisms that play significant ecological roles and exhibit diverse nutritional strategies. They can be found in various environments, including freshwater, marine habitats, and soil. Understanding the nutritional requirements and mechanisms of nutrient acquisition…

INTRODUCTION Phylum Platyhelminthes, commonly known as flatworms, is a diverse group of invertebrates that exhibit unique characteristics and adaptations. This phylum consists of various species, including parasitic and free-living flatworms. In this article, we will explore the characteristics of Phylum Platyhelminthes, their classification, adaptations, ecological roles, and provide examples of…

INTRODUCTION Phylum Cnidaria encompasses a diverse group of marine organisms, including jellyfish, corals, sea anemones, and hydroids. These organisms share several characteristic features that define the phylum. In this article, we will explore the characteristics of Phylum Cnidaria, its classification, unique adaptations, ecological significance, and provide examples of organisms within…

LARVAL FORMS OF ECHINODERMS :- Echinoderm larva is strikingly bilaterally symmetrical in marked contrast to radially symmetrical adult. It swims about by means of a ciliated band, which may be complicated by a number of short or long slender projection or arms from the body wall. Based upon the nature and position of the arms or their absence, lame of different classes of Echinodermata may distinguished.

LARVAL FORMS OF MOLLUSCA :- Molluscan life histories do not perfectly correspond with taxonomy, but in general it is true that the archaeogastropods and the bivalves begin life as a trochophore and rapidly pass on to a veliger. There are different types of molluscan larvae according to the importance of the pelegic phase and amount of planktonic food taken. G. Thorson (1950) recognised three ecological types of larvae in Mollusca.

LARVAL FORMS OF CRUSTACEA :- Crustaceans show both direct and indirect development. In direct development (e.g„ Palaemon, crayfish), the adult is attained by progressive growth and differentiation of the embryo, so that the newly hatched young resembles the parents in general structure.

LARVAL FORMS OF TREMATODA, CESTODA AND ANNELIDA :- The trematods or flukes are either external or internal parasites, the cestodes or tap worms are internal parasites. The termatoda class includes three order . The fasciola hepatica which is an example of order digenea have mainly 5 larval forms (i) miracidium (ii) sporocyst (ii) redia (iv) Cercaria (v) metacercaria.

Nervous system in mollusca has a well developed nervous system. It also bears paired ganglia, nerves and connectives. One important aspect is there that a Circumentric ring is formed by ganglia. A pair of cerebral ganglia (masses of nerve cell bodies) innervate the head, mouth, and associated sense organs. NERVOUS SYSTEM IN MOLLUSCA​

NERVOUS SYSTEM IN ARTHROPODA​ is as advance as in Annelida. There is dorsal brain again connected with nerve ring to ventrae nerve cord. The arthropod nervous system consists of a dorsal brain and a ventral, ganglionated longitudinal nerve cord (primitively paired) from which lateral nerves extend in each segment.

The advanced nervous system in annelids is generally compare with coelenterates. The well developed nervous system can be seen here in form of a pair of cerebral ganglia (brain) and a double ventral nerve cord. This ventral nerve cord bears ganglia and lateral nerve in each segment as annelids are true segmented animals.

NERVOUS SYSTEM OF COELENTERATE AND ECHINODERM is not complex.  Hydra and jelly fish possesses diffused nervous system, diffused nervous system is most primitive form of nervous system. Nerve cells are distributed beneath the outer epidermis. Brain is absent though there can be concentrated neuron present locally and ganglia are present.

Regulation of osmotic pressure of an organism body fluid is refer to as osmoregulation. It allow to maintain balance of water content, fluid content and electrolytes. Hence due to osmoregulation body neither become too dilute nor become too concentrated. Right concentration of solute and amount of water must be maintain by any aquatic [fresh or marine] and terrestrial organisms. It can be mostly achieved by excretion.

EXCRETION IN HIGHER TERRESTRIAL INVERTEBRATES :- Excretory system regulates the amount of nitrogenous material, inorganic salts and water content in the blood. Both cockroach and earthworm are terrestrial in habitat their excretion is discuss in detail.

EXCRETION IN HIGHER AQUATIC INVERTEBRATES :- Process by which nitrogenous waste produce during metabolism is removed is known as excretion. Some animals such hydra, echinoderms and other may not posses proper excretory organs the reason is quite clear that they are aquatic and it is supposed that nitrogenous material may be diffuse out of there body through their body surface.

EXCRETION IN LOWER INVERTEBRATES :- Every organism possess different mechanisms, organs and different excretory product. For example porifera and hydra can perform excretion through body surface where as platyhelminthes possess a specialised cells known as flame cells.

ORGANS AND MECHANISM OF RESPIRATION IN HIGHER INVERTEBRATES :- There are generally three common ways through which invertebrates can perform the process  of respiration. These are cutaneous respiration which is mainly performed by lower invertebrates and annelids other is respiration through trachea and gills.

ORGANS AND MECHANISM OF RESPIRATION IN LOWER INVERTEBRATES :- In terms of biochemistry respiration is chemical reaction which occur in all living cell that provides energy after breakdown of glucose. Now respiration can be divided into two categories first aerobic respiration and other is anaerobic respiration.

PATTERN OF FEEDING AND DIGESTION IN HIGEHER INVERTEBRATES :- There are various mechanism for capturing and feeding over prey or food these are as follow Leeches generally feed over the fluid and soft tissue by piercing and then sucking from their host and simply absorbs the blood from the prey or host

PATTERN OF FEEDING AND DIGESTION IN LOWER INVERTEBRATES :- Every organism needs energy to perform its basic metabolic function. This energy can be obtain from food and sun. As sun is a universal source of energy but only autotrophic organism can obtain energy from sun.

The Ectoprocta are minute, sessile, colonial, unsegmented coelomate animals. Provided by the circular or cresentic lophophore, a u-shaped alimentary canal with anus opening near the mouth but outside of lophophore. Usually posses free swimming larva but without nephridia or circulatory system.

The Entoprocta or Endoprocta are group of small sessile aquatic animals. In which the body cavity is believed to be pseudocoel. They were formerly include in the phylum Bryozoa which however are true coelomate animals.

The Phoronida, brachiopod and Ectoprocta are collectively called as lophophorates coelomates because they all posses lophophore.

The word Rotifera is derived from latin meaning wheel barrier. They are commonly known as “wheel animalcules” as they are rotating wheel like structures

Hydrostatic movement occur when dominantly muscles are involved in their movement many organism show such kind of movement including Hydra, Earthworm, Leeches and Echinoderms.

LOCOMOTION IN PROTOZOA :- Moving ones body is an essential need of any organism. Some organism are sessile while other moves at very high speed. Some organisms moves very slowly such as amoeba or euglena where as other can move fastest example leopard.

The word coelom describes the body cavity that is internal space. But there can be difference in coelom true coelom will always be fluid filled lying between outer bodywall and inner digestive tube. It arises between two layers of embryonic mesoderm and consist of most of the visceral organs.

Metazoans can be define as multicellular organisms or as cellular animal or more accurately simply as animals.They are holozoic multicellular organisms.