What are Phylum and Subphylum in Animal Kingdom with Key Characteristics and Examples
All creatures are members of the Kingdom Animalia, also called Metazoa. This Kingdom doesn't contain prokaryotes (Kingdom Monera, which includes bacteria, blue-green algae) or protists (Kingdom Protista, which includes unicellular eukaryotic organisms). All members of Animalia are multicellular, and all are heterotrophs (that is, they calculate directly or laterally on other organisms for their ailment). Most ingest food and digest it in an internal depression.
It's estimated that around 9 or 10 million species of creatures inhabit the earth; the exact number isn't known and all estimates are rough. Creatures range in size from no further than many cells to organisms importing numerous tons, similar to blue jumbos and giant squid. By far most species of creatures are insects, with groups similar as molluscs, crustaceans, and nematodes also being especially different. By this measure, our own group, the invertebrates, is fairly inconsequential from a diversity perspective.
R.H. Whittaker organized organisms into five kingdoms. He classified organisms supported cell structure, mode, source of nutrition and body design. The five kingdoms proposed by Whittaker are Monera, Protista, Fungi, Plantae, and Animalia. Let us learn about the animal kingdom, i.e., Kingdom Animalia.
Kingdom Animalia
Kingdom Animalia constitutes all animals. Amongst the five kingdoms, the most important kingdom is Animalia. Animals are multicellular eukaryotes. However, like plants, they do not possess chlorophyll or a cell membrane. Therefore, members of the Animalia exhibit a heterotrophic mode of nutrition. Kingdom Animalia has been classified into ten different subphyla supported their body design or differentiation.
The different phylum of the Animalia are as follows:
Porifera
Coelenterata (Cnidaria)
Platyhelminthes
Nematoda
Annelida
Arthropoda
Mollusca
Echinodermata
Hemichordata
Chordata
Phylum Porifera
Porifera means organisms with holes. They are commonly known as Sponges. Features of the Porifera are:
Non-motile, multicellular organisms with a hard outer skeleton.
Have a porous body.
Pores on the bodies create a canal system that helps in the circulation of drugs.
Their body does not include a typical head and tail; well-developed organs or organ systems are absent.
Include marine habitat.
Example of phylum Porifera includes- Spongilla, Sycon.
Phylum Coelenterata (Cnidaria)
The term Coelenteratais derived from the Greek word “kilos” which suggests hollow-bellied. Their features are:
Have a hollow body cavity.
The body is differentiated into two ends.
Includes all aquatic animals.
The body is formed of two layers of cells: inner and outer linings.
They are either found solitarily (Sea anemone) or in colonies (corals).
Example of phylum Coelenterata includes – Hydra, Jellyfish.
Phylum Platyhelminthes
Platyhelminthes are commonly known as flatworms. Their features are:
Dorsoventrally flattened body.
Complex and have differentiated body structure.
They are triploblastic, i.e. tissue is differentiated from three distinct cell layers.
Do not have a real internal cavity or coelom.
Have bilateral symmetry.
Either free-living (Planaria) or parasitic (liver flukes).
Example of phylum Platyhelminthes includes -Tapeworm, Planaria.
Phylum Nematoda
Phylum Nematoda consists of nematodes or roundworms. Their features are:
Nematodes have a cylindrical body.
Bilaterally symmetrical and triploblastic.
Have pseudocolour, a false body cavity.
Parasitic and causes diseases such as elephantiasis, ascariasis.
Example of phylum Nematoda includes – Ascaris, Wuchereria.
Phylum Annelida
Annelids are commonly referred to as segmented or ringed worms. They have the following features:
Have a segmented cylindrical body.
The body is differentiated into the head and tail.
Bilaterally symmetrical and triploblastic.
Have a true body cavity.
Habitat: marine, freshwater, and land.
Example of phylum Annelida includes – Earthworm, Leech.
Phylum Arthropoda
Arthropod means jointed legs. Animals that have jointed appendages belong to the present phylum. This is the most important phylum within the Animalia. Other features are:
They are bilaterally symmetrical.
Have jointed appendages, exoskeleton, and a segmented body.
Have a well-differentiated organ and organ system.
Have an open cardiovascular system, but don't have differentiated blood vessels.
Examples include – butterflies, spiders and mosquitoes.
Phylum Mollusca
Phylum Mollusca consists of an outsized group of animals. Features are:
Bilaterally symmetrical and triploblastic.
Less segmented body.
Well-developed organ and organ system.
Typically, an open circulatory system is present.
Limbs are present.
Example of phylum Mollusca includes- Snails and octopus.
Phylum Echinodermata
The term Echinodermata springs from the Greek words, ‘echinos’ meaning hedgehog and derma meaning skin. Thus, echinoderms are spiny-skinned animals.
Radial symmetry and triploblastic.
Have true coelom.
Have a hard calcium carbonate skeleton structure.
Free-living marine animals.
Example of phylum Echinodermata includes- Sea urchins, starfish.
Phylum Hemichordata
The characteristics of the phylum Hemichordata are as follows:
Soft and fragile body divided into a proboscis.
The epidermis is single-layered.
Includes marine animals (worm-like) with an organ-system organization level.
They have an open circulatory system.
They respire through gills since they are marine.
Sexes are separate and fertilization is external.
Development is direct.
Phylum Chordata
The Chordates possess the following characteristics:
Body bilaterally symmetrical, with an organ-system organisation level and are triploblastic.
They possess a notochord and a nerve cord.
The circulatory system is closed type.
Phylum Chordata is often divided into the subsequent sub-phyla:
Urochordata
Cephalochordata
Vertebrata
Hence Animalia is the largest kingdom amongst the five kingdoms consisting of all animals. Animals are multicellular eukaryotes; don't possess a cell membrane or chlorophyll like plants, and share an equivalent mode of nutrition, that is, the heterotrophic mode. Among the other prominent characteristics of this kingdom include body symmetry, cell arrangement, extent of organization, presence/absence of notochord, etc.
FAQs on Animal Kingdom Animalia Classification into Phylum and Subphylum
1. What is Animal Kingdom Animalia?
The Animal Kingdom (Kingdom Animalia) is a major biological kingdom that includes all multicellular, eukaryotic, heterotrophic organisms commonly known as animals.
Key characteristics of Animalia include:
- Cells lack a cell wall
- Body made of many specialized cells
- Heterotrophic mode of nutrition (ingest food)
- Usually capable of movement at some life stage
- Mostly reproduce sexually
2. What are the main characteristics of Kingdom Animalia?
The main characteristics of Kingdom Animalia are multicellularity, heterotrophic nutrition, and absence of cell walls.
Important features include:
- Cells are eukaryotic with a true nucleus
- Nutrition is holozoic (food is ingested and internally digested)
- Presence of specialized tissues like muscle and nerve tissue (in higher animals)
- Body shows definite symmetry (asymmetrical, radial, or bilateral)
- Reproduction mainly by sexual reproduction
3. What is a phylum in the Animal Kingdom?
A phylum is a major taxonomic category below kingdom that groups animals based on a common body plan and fundamental structural features.
In Animalia, organisms in the same phylum share:
- Basic body organization
- Similar embryonic development patterns
- Common structural characteristics
4. What is a subphylum in biological classification?
A subphylum is a taxonomic rank below phylum and above class that further divides a phylum into more specific groups.
It is used when a phylum is large and diverse. For example, in Phylum Chordata, the subphyla are:
- Urochordata
- Cephalochordata
- Vertebrata
5. What are the major phyla of the Animal Kingdom?
The major phyla of the Animal Kingdom are groups of animals classified by body structure and organization.
Important animal phyla include:
- Porifera – sponges
- Cnidaria – jellyfish, corals
- Platyhelminthes – flatworms
- Nematoda – roundworms
- Annelida – segmented worms
- Mollusca – snails, octopus
- Arthropoda – insects, crabs, spiders
- Echinodermata – starfish
- Chordata – animals with a notochord
6. What is the difference between phylum and subphylum?
The main difference between phylum and subphylum is that a phylum is a broader taxonomic group, while a subphylum is a subdivision within a phylum.
Comparison:
- Phylum: Groups organisms with a common basic body plan (e.g., Chordata)
- Subphylum: Further divides a phylum based on detailed differences (e.g., Vertebrata under Chordata)
7. What is Phylum Chordata and why is it important?
Phylum Chordata includes animals that possess a notochord at some stage of their life cycle.
Key characteristics of Chordata are:
- Presence of a notochord
- Dorsal hollow nerve cord
- Pharyngeal gill slits
- Post-anal tail
8. How are animals classified into different phyla?
Animals are classified into different phyla based on their body organization, symmetry, germ layers, and presence of body cavity.
Main criteria used in classification include:
- Level of organization (cellular, tissue, organ-system)
- Type of symmetry (radial or bilateral)
- Number of germ layers (diploblastic or triploblastic)
- Type of coelom (acoelomate, pseudocoelomate, coelomate)
- Segmentation and presence of a notochord
9. Which is the largest phylum in the Animal Kingdom?
The largest phylum in the Animal Kingdom is Arthropoda.
Characteristics of Arthropoda include:
- Jointed appendages
- Segmented body
- Hard chitinous exoskeleton
- Open circulatory system
10. What are examples of subphyla in Chordata?
The main subphyla of Phylum Chordata are Urochordata, Cephalochordata, and Vertebrata.
Examples include:
- Urochordata – Sea squirts (e.g., Herdmania)
- Cephalochordata – Lancelet (e.g., Branchiostoma)
- Vertebrata – Animals with a vertebral column (e.g., fishes, birds, mammals)
