Animal

The diversified world around us, with millions of biotic and abiotic components that contribute to the formation of our ecosystem, is nothing short of a wonder. There are two primary kinds of organisms that make up the biotic or living community. The first is plants and the second is animal life. In this topic, we will look at the kingdom animalia and the numerous phyla that it contains, as well as the characteristics that distinguish them.

Animal Cell Diagram

Chordates make up only 5% of the animal kingdom, with invertebrates accounting for the vast majority of the remaining 95%. Vertebrates are a subphylum of chordates, and they are distinguished by the existence of a vertebral column or backbone in their bodies. With the exception of sponges, all animal cells are organised into tissues, and in the vast majority of cases, the tissues organise to create well-defined organs and organ systems that perform vital duties for the body. In nature, the vast majority of animals are likewise diploid, and they reproduce sexually through the creation of gametes.The primary phyla that make up the animal world, as well as the characteristics that distinguish them from one another, are listed in the following list.

Porifera 

• Species such as sponges, which are multicellular, primitive animals with cellular grade organisation, represent the Porifera phylum.

• They are aquatic life forms that are free-living and do not have a set body shape or plane of symmetry. Even a few disconnected cells from a pre-existing sponge can be used to regenerate a new sponge.

These organisms are primarily found in marine environments, and they are distinguished by a body wall that is composed of two layers of loosely distributed cells with a mesenchyme between them. A vast cavity (spongocoel) exists within the body wall, 

which is mostly of a multitude of small canals that transport oxygen and food to the cells and remove poisonous waste materials from the body.

As an illustration, consider the word Spongilla (freshwater sponge)

Cnidaria 

• The coelenterates, which are members of the phylum Cnidaria, are radially symmetrical and have a tissue-level organisational system (their tissues do not form organs).

• The polyp and the medusa are the two most common types of bodies found on the organisms. The former has a fixed structure and is cylindrical in shape, whereas the latter is freely swimming and has an umbrella-shaped shape. This type of polymorphism can be found in a variety of forms among the members of this phylum, and it can occur in several varieties. The majority of the time, when both forms are seen in the same organism, they alternate in the life cycle, a phenomenon known as alternation of generation.

As an illustration, Adamsia (sea anemone) and Meandrina (Brain coral)

Platyhelminthes 

• The members of the phylum Platyhelminthes are bilaterally symmetrical animals with organ-system level of organisation, as opposed to the rest of the animal kingdom.

• Flatworms, which are members of the phylum Platyhelminthes, are characterised by the absence of body cavities (acoelomate) as well as the absence of functional circulatory and respiratory functions. The flatworms’ bodies are packed with organs, which are held together by parenchyma, a form of connective tissue.

However, the creatures do not have anus, but they do have a mouth.

• Internal reproduction is the mode of reproduction. Because the animals are hermaphroditic in nature, extensive efforts are made to guarantee that the incidence of self-fertilization is kept to a bare minimum.

As an illustration, Fasciola (liver fluke)

Aschelminthes

• They are likewise triploblastic organisms, with a pseudocoelom separating the stomach from the rest of the organism’s structure. Because the cavity is not lined with mesodermal epithelium, the members of the aschelminthes family are categorised as pseudocoelomates, or organisms that lack a real body cavity, despite the fact that they do exist.

• In order to build the body wall, three layers are required: a hard, resistant cuticle, a muscle layer, and an epidermis. The latter can take on both cellular and syncytial characteristics.

• Different creatures have reproductive organs that are diametrically opposed to one another, and fertilisation occurs within. Sexual reproduction is the mode of reproduction.

• Nematodes are the most important of the phylum’s diverse members, and they are the most numerous. They may live in both aquatic and terrestrial environments and are parasitic in their natural environment.

As an illustration, Wuchereria bancrofti (filarial worm)

Annelida 

• Members of the phylum Annelida are triploblastic, which means that they emerge from a three-layer germ layer arrangement and have bodies that are bilaterally symmetrical. A real coelom or body cavity is also present, which is bordered by a layer of mesodermal epithelium, indicating that they are living organisms.

• The body is elongated, flattened, or cylindrical in shape, and ring-like grooves, known as annuli (from which the phylum’s name is derived), split the body into segments. The phylum is named after the ring-like grooves that divide the body into segments.

• The animals in this phylum also have a properly functioning closed circulatory system as well.

For instance, Hirudinaria (leech) and Pheretima (earthworm)

Arthropoda 

• The arthropods, the largest phylum in the animal kingdom and the most complex in terms of organ-system organisation, have bodies that are bilaterally symmetrical and triploblastic. They also have a real bodily cavity, known as a coelom (coelomates).

• All members of this phylum are distinguished by the presence of an exoskeleton consisting of chitinous cuticles, which distinguishes them from one another. The cuticle sheds and is replaced by a new one on a regular basis in order to keep up with the growth of the organism.

• The body of an arthropod is divided into four sections: the head, the thorax, the abdomen, and the jointed appendages.

• They have an open circulatory system that connects to a bodily cavity known as the haemocoel, which allows them to breathe freely. The respiratory and excretory organs of different creatures are different from one another.

For instance, Apis (honey bee) and Periplaneta are both species of Apis (cockroach)

Mollusca 

• Mollusca, the second-largest phylum in the biological kingdom, includes familiar aquatic species such as snails, slugs, octopuses, oysters, and other similar creatures.

• They have organ-level order in their systems, and their bodies are bilaterally symmetrical, triploblastic (made up of three germ layers), and coelomate (with three germ layers) (containing true body cavity, lined by mesodermal epithelium). Calcareous shells cover most of the creature’s body, which is divided into three sections: the head region, the visceral hump, and the muscular feet.

• The nephridium serves as an excretory organ, removing waste products from the body as needed. The open circulatory system is present in all mollusks, with the exception of cephalopods.

Examples are the Pila (apple snail) and the Dentalium (tusk shell)

Echinodermata 

• Triploblastic, coelomate animals belonging to the phylum Echinodermata are found in the ocean’s depths and are found on the seafloor (banthoic). The mature organisms are radially symmetrical, whereas the larval species demonstrate bilateral symmetry during their development.

• The presence of a water circulatory system in the bodies of the phylum Echinodermata is the most distinguishing characteristic of this group of organisms. Swimming is not a problem for them, and their tube feet are contractile appendages that provide a variety of purposes like movement, breathing, and food capture, as well as maintaining the body’s attachment to the substrate.

• The mode of reproduction is sexual, and fertilisation takes place outside of the body.

Antedon (sea urchin), Echinoidea (sea urchin), and others.

Protochordate 

• Known as protochordates or hemichordates, protochordates are exclusively marine organisms that are organised at the organ system level of organisation.

• Their bodies are bilaterally symmetrical, triploblastic, and comprise a genuine body cavity, known as the coelom, within which they live. An anterior proboscis, a lengthy trunk, and a collar are the main components of the body’s cylindrical shape and structure. The notochord is hollow and develops from the endodermal germ layer of the embryonic stem cell layer.

• The mode of reproduction is sexual, and fertilisation takes place outside of the female reproductive system. The circulatory system is fully functional.

Ptychodera and Balanoglossus are two examples (tongue worm)

Chordata 

• Triploblastic animals, such as those belonging to the phylum Chordata, exhibit bilateral symmetry and organ system level of organization, in addition to having a genuine coelom. The existence of a notochord, a dorsal, hollow nerve cord, and paired pharyngeal slits are the most distinguishing characteristics of this phylum of animals.

• Subphylum Vertebrata is included within this phylum; the animals that belong to this group have a backbone or vertebral column, which is where the name “vertebral column” comes from. The subphylum urochordata and cephalochordata are the other two subphylums of Chordata.

These animals are classified into four groups: birds (Aves), reptiles (Reptilia), amphibians (Amphibia), fishes, and mammals (Mammalia).For instance, Scoliodon (dog fish), Betta (fighter fish), Bufo (toad), and Draco are all fish. (flying lizards), Corvus (crow), Panthera leo (lion), and Homo sapiens are some of the species represented (Human).

Conclusion

In ecology, a habitat is described as a natural environment that can support the survival and reproduction of a specific species throughout the year, or for shorter periods of time during specific seasons. Such habitats are made up of biotic and abiotic components, as well as other resources that are necessary for the survival of life.

In ecology, a microhabitat is a tiny environment that differs only slightly from the surrounding habitat. These habitats contain species that are not found in the larger habitat and are therefore considered to be unique. A microhabitat can be anything from a small pool of water to the underside of a rock to a decomposing log, to name a few examples.