Classification of Living Organisms (Animalia)

Introduction

These include all living organisms that are multicellular eukaryotes without cell walls. They are heterotrophs and mostly mobile. They are further classified based on the extent and type of body design differences.

Porifera:

• The word Porifera means organisms with holes
• These are immobile animals that attach to a solid support. There are openings or ‘pores’ all around the body
• These openings lead to the trench framework, which courses water all through the body to bring food and oxygen
• Hard outer layer animals are hard and are also called skeletons
• Body design involves very little differentiation and tissue division
• These are called sponges and are found in marine habitats
• Examples: Euplectella, Sycon Spongilla

Coelenterata (cnidaria):

• These are animals living in the water
• They show more body design differentiation. The cavity is present In their body
• The body is made up of two layers of cells: one that forms the outer cells of the body, and the other that forms the inner lining of the body
• Some of these species live in colonies (Corals), while others have solitary (Hydra)
• Examples: Jellyfish and sea anemones

Platyhelminthes:

• Their body is smooth in two ways: the design of the left and right parts of the body is the same
• In any case, there is no evident inward body hole or coelom, in which very much created organs can be obliged
• The body is dorsoventrally flattened (ie from top to bottom), which is why these animals are called flatworms
• Examples: Planarians, or parasitic animals like liver flukes

Nematoda:

• Their bodies are also bilaterally symmetrical and triploblastic. However, the body is cylindrical rather than flat
• There are tissues, yet no genuine organs, albeit a kind of body depression or a pseudocolour, is available
• These parasites are well known as insects that cause diseases, such as elephantiasis (filarial worms) or intestinal worms (roundworms or pinworms)
• Examples: Ascaris, Wuchereria

Annelida:

• These are also bilaterally symmetrical and triploblastic, but in addition, they have a true body cavity. There is, thus, extensive organ differentiation
• This distinction is made in a segmented manner, the parts of which are lined up one after the other from head to tail
• These creatures are found in an assortment of environments – new water, marine water just as land
• Examples: Earthworms and leeches

Arthropoda:

• This is likely the biggest gathering of creatures
• Arthropods are bilaterally symmetrical and segmented
• There is an open circulatory framework: blood doesn’t stream in obvious veins
• The coelomic cavity is blood-filled
• Examples: houseflies, spiders, scorpions, prawns, butterflies, and crabs

Mollusca:

• In the creatures of this gathering, there is respective evenness. The coelomic cavity is reduced. There is little segmentation
• These types have an open circulatory system. There is afoot that is used for walking
• Examples: Snails and mussels

Echinodermata:

• In Greek, Aquinas means hedgehog, and derma means skin. As such, they are fleshy-skinned creatures
• These are exclusively free-living marine animals
• These are triploblastic and they have a coelomic cavity inside
• They also have a special water-powered tube system that they use to move around
• They have strong calcium carbonate structures which they use as skeletons
• Examples: Sea-stars and sea urchins

Protochordate:

• These animals are bilaterally symmetrical, triploblastic, and coelom
• In addition, they show a new feature of body design, namely a nocturnal, at least in some stages of their lives
• A notochord is a long rod-like support structure (chord = string) that separates the animal’s back as well as the nerve tissue from the gut
• It provides space for muscle contraction to facilitate movement
• They may not have a proper notochord present at all stages in their lives or for the entire length of the animal
• Protochordate is marine animals
• Examples: Balanoglossus, Herdmania, and Amphioxus

Vertebrata:

• These animals have a real vertebral column and an internal skeleton, which can be used to move a very different distribution of muscle joints
• Phrases are bilaterally symmetrical, triploblastic, colloquial, and segmented, with complex distinctions of body tissues and organs
• All chordates have the following characteristics: (i) a notochord (ii) a dorsal nerve bone (iii) are triploblastic (iv) paired flower pouches (v) are colloidal
Vertebrates are further grouped into six classes:

Cyclostomata:

• Cyclostomes are jawless vertebrates. They are characterized by a long elliptical body, circular mouth, thin skin, and no scales
• They are borders of ectoparasites or other vertebrates
• Petromyzon (Lamprey) and Myxine (Hagfish) are examples

Pisces:

• These are fish. These are exclusively aquatic animals. Their skin is covered with scales/plates. They obtain oxygen with the help of gills
• The body is smooth, and a muscular tail is used for movement
• They are cold-blooded and have only two rooms in their hearts as opposed to four human beings. They lay eggs
• Some have skeletons made entirely of cartilage, such as sharks, and some have skeletons made of both bone and cartilage

Amphibia:

• These animals are different from fish because of their lack of scales, mucus glands in the skin, and three-chambered hearts
• Respiration is through either gills or lungs
• They lay eggs
• Found in water and as well as on land
• Examples: Frogs, toads, and salamanders

Reptilia:

• These cold-blooded animals have skulls and the ability to breathe through their lungs
• While most of these hearts have three chambers, crocodiles have four chambers
• They can give eggs with tough coverings
• Examples: Snakes, turtles, lizards, and crocodiles

Aves:

• These are warm-blooded creatures and have a four-chambered heart. They lay eggs
• There is an external covering of quills, and two forelimbs are adjusted for flight
• They inhale through their lungs
• All birds fall in this classification

Mammalia:

• Well evolved creatures are warm-blooded creatures with four-chambered hearts
• They have mammary organs to create milk to sustain their young
• Their skin has hairs comparably sweat and oil organs
• Most warm-blooded animals natural to us produce live youthful ones
• Few mammals like the platypus and the echidna lay eggs and some like kangaroos give birth to very poorly developed young ones
• Examples: Cat, Rat, Bat, and Human

Conclusion

Animalia is the last kingdom given in the classification by Whittaker. His classification is based on the cell structure, mode, and source of nutrition, as well as the body’s structure. Animalia is an important part of the classification of living organisms.