Classification of Animals with Examples for NEET By Vedantu
NEET question paper has three sections- Biology, Chemistry, and Physics, each carrying 45 marks. Biology is further divided into Botany and Zoology (45 marks each). To score well, students must be strong in both sections. For Zoology, referring to Animal Kingdom Class 11 notes is helpful. Zoology is the branch of biology that studies animals and their importance.
Kingdom Animalia
All living organisms, past and present, are classified into five kingdoms
Animalia
Plantae
Monera
Fungi
Protista.
The Animal Kingdom is highly diverse, with differences in body structure, genetics, and morphology. However, all animals share common features that set them apart from other kingdoms. Understanding these differences is essential for NEET Biology preparation.
Some of These Features are Discussed Below –
Animals are eukaryotes and multicellular. They have specially evolved tissue structure that enables them to perform an array of functions.
All animals are heterotrophs. It means that they cannot make their food like autotrophs. Instead, they meet their nutrition requirements by consuming organisms that sit lower than them on the food chain.
Based on nutrition intake, animals are divided into herbivores, carnivores, and omnivores. Animal kingdom class 11 notes for NEET pdf explains in detail the difference between animals based on their diet choice.
Unlike plants, animals are motile or capable of movement as they need to gather their food from external sources. Additionally, animals have specially evolved organs which facilitate them to catch or avoid their prey.
Most members of kingdom Animalia carry out sexual reproduction. During fertilization, the sperm and egg fuse to form a zygote. Fertilization may be internal or external. You can refer to animal kingdom class 11 notes for NEET to learn more about the different modes of reproduction.
In some animals such as mammals, the offspring resembles the adult. Other animals like insects and amphibians pass through several larval stages.
Classification of Kingdom Animalia
Kingdom Animalia is further classified into subgroups based on the following points. Go through animal kingdom class 11 notes for NEET to gain more clarity on these classifications.
Cellular arrangement in animals.
Tissue or organ system organization.
Based on symmetry.
Absence or presence of body cavity.
Based on segmentation.
Presence and absence of Notochord.
According to the above classification, members of kingdom Animalia falls into the following categories -
Phylum Porifera- Asymmetrical animals such as sponges belong to this category. Most of them are marine animals. These organisms have a cellular level of organization. They have pores in their body through which they absorb water, dispose of bodily waste, and carry out respiratory exchanges. Moreover, these animals don’t have any separate sexes, so asexual reproduction takes place. A skeleton made up of spongin fibers can be seen in members of this phylum.
Phylum Cnidaria- The members of this group are mostly aquatic, common in marine habitats. They are symmetrical animals with tissue-level organisation, a gastro-vascular cavity, and mouth on hypostome.
Cnidarians mainly have two body types – polyp and medusa. Digestion in these animals takes place both intracellular and extracellular. Some animals belonging to this phylum are Physalia, Adamsia, pennatula etc.
Phylum Ctenophora- Members of this species are most often referred to as sea walnuts or comb jellies. They are radially symmetrical, diploblastic with tissue level organisms. They have external ciliated comb plates which facilitate locomotion. One of the main features of this group of animals is bioluminescence. Examples are ctenoplana, Pleurobrachia, etc.
Phylum Platyhelminthes- Animals belonging to this phylum are called flatworms because of their dorso-ventrally flattened physical structure. They can be found in other animals and human beings as well. They have organ level organization, are bilaterally symmetrical, triploblastic and acoelomate. Specialized cells for osmoregulation and excretion are present in these animals. Some members of this group take their nutrition from a host animal. Examples are Taenia, Fasciola.
Phylum Aschelminthes- Because of the circular structure, members of this group are called roundworms. They can be a free-living, parasitic, or aquatic and terrestrial animal. Like tapeworms, they have organ level organization, are bilaterally symmetrical, triploblastic and pseudocoelomate. Additionally, they have a Muscular pharynx, excretory tube and separate sexes. Some examples are Ascaris, Ancylostoma etc.
Phylum Annelida- Members of this group such as Nereis, Pheretima show organ level organization, are triploblastic, metamerically segmented and coelomate. They have longitudinal and circular muscles that help them to move. Animals of phylum Annelida have a closed circulatory system, neural system and organs that help in osmoregulation and excretion. You will gain a better understanding of the organ system of Phylum Annelida with animal kingdom class 11 notes for NEET.
Phylum Arthropoda- This group includes insects and is one of the largest groups. Members of this group share the following features –
Exoskeleton.
Head.
Thorax.
Abdomen.
Jointed appendages.
Respiratory organs such as gills, tracheal system, etc.
Open circulatory system.
Sensory organs like antennae, eyes, etc.
Malpighian tubes through which excretion takes place.
Examples are apis, bombyx, cockroach, etc.
Phylum Mollusca- Animals of this group are terrestrial or aquatic organisms with organ system organization who are dioecious and oviparous. Their body is separated into a head, muscular foot and visceral hump. The anterior head contains sensory organs, and the mouth has a file-like rasping organ, feathery gills.
Phylum Echinodermata- The members are all marine animals with organ-level organization. Adults are radially symmetrical whereas larvae are bilaterally symmetrical. Other organs include – fully formed digestive system, mouth and anus. These animals also have a water vascular system which facilitates locomotion, transport of food and respiration.
Phylum Hemichordata- Worm-like marine animals fall under this phylum. They have a cylindrically shaped body which has an anterior proboscis, trunk, and collar. Animals of this phylum have open circulation and carry out external circulation. Some examples are Balanoglossus and Saccoglossus.
Phylum Chordata- Members of this group share some characteristic features. These are – notochord, dorsal hollow nerve, paired pharyngeal gill slits. They also have a post-anal tail and closed circulatory system. This group is further divided into – Vertebrata, cephalochordate, and Urochordata. Furthermore, Vertebrata is further subdivided into Cyclostomata, Chondrichthyes, Osteichthyes, amphibia, reptilia, aves, and Mammalia.
Class I – Cyclostomata (Jawless Fishes)
Characterised by a circular, sucking mouth without jaws
Functions as ectoparasites on fishes
Possess 6-15 pairs of gill slits
Lack of scales and fins
Have a cartilaginous vertebral column and cranium
The circulatory system is of a closed type
Found in marine environments but migrate to freshwater for reproduction; adults die post-spawning, while larvae return to the ocean after metamorphosis
Examples- Petromyzon (Lamprey), Myxine (Hagfish)
Class II – Chondrichthyes (Cartilaginous Fishes)
The endoskeleton is made of cartilage, with a ventrally located mouth
Gills are exposed as they lack an operculum
Notochord remains throughout life
Have placoid scales, making their skin rough and tough
Must keep swimming to prevent sinking as air bladders are absent
Have a two-chambered heart and are cold-blooded (poikilotherms)
Exhibit separate sexes, internal fertilisation, and many are viviparous
Males have claspers on the pelvic fin
Some species possess electric organs (Torpedo), while others have venomous stings (Trygon)
Examples- Scoliodon (Dogfish), Trygon (Stingray), Pristis (Sawfish), Carcharodon (Great White Shark)
Class III – Osteichthyes (Bony Fishes)
Possesses a streamlined body with a bony endoskeleton
Have four pairs of gills covered by an operculum
Skin is covered with cycloid scales
Have a two-chambered heart and an air bladder for buoyancy
Cold-blooded (poikilotherms)
Separate sexes, oviparous, external fertilization, and direct development
Examples-
Marine- Hippocampus (Seahorse), Exocoetus (Flying Fish)
Freshwater- Labeo (Rohu), Clarias (Magur), Catla (Katla)
Aquarium Species- Betta (Fighting Fish), Pterophyllum (Angelfish)
Super Class - Tetrapoda
A well-devised preparation strategy will go a long way towards helping you to revise each topic efficiently and ultimately help you ace NEET. Thus, while strategising your study plan, make sure to dedicate equal time to each topic. Focus on the weak points by referring to study guides like Animal Kingdom Class 11 notes for NEET.
Essential Study Materials for NEET UG Success
Additionally, you can also consider going through biomentor notes for more systematic NEET preparation.
FAQs on The Animal Kingdom - Important Notes for NEET Biology
1. What are the features of vertebrates?
Vertebrates have a bilaterally symmetrical body along with the fully developed head, trunk and tail. They also have two pairs of appendages. In vertebrates, there are several basic features. First, they have a complex central nervous system. The central nervous system includes a well-developed brain and a spinal cord that is enclosed in the vertebral column. They also have a closed circulatory system. The blood of vertebrates circulates in blood vessels. Vertebrates also have hair, feathers, or scales covering their skin. These cells develop into nerve cells and cells that form facial structures. In addition to these basic characteristics, there are five key characteristics that are common to all vertebrates. These are:
Vertebral column: The vertebral column is a series of small bones that make up the backbone.
Skull: Vertebrates have a skull, which protects the delicate, well-developed brain.
Endoskeleton: Vertebrates have a highly developed endoskeleton, which is their internal skeleton.
Bilateral Symmetry: These organisms are bilaterally symmetrical, meaning they have mirror-image right and left hemispheres.
2. How Many Species Fall Under Phylum Arthropoda?
Arthropods include a wide variety of animals with hard exoskeletons and jointed appendages, including insects, spiders, scorpions, centipedes, and millipedes on land; crabs, crayfish, shrimp, lobsters, and barnacles in the water. Over 85 percent of all animal species are arthropods. They inhabit the greatest variety of habitats and consume the greatest variety of food.
Around 750,000 known species can be categorised under phylum Arthropoda. You can learn more about the species in Animal Kingdom class 11 notes for NEET from here.
3. What are some of the specialised tissues found in animals?
The main specialised tissues in animals are nervous, epithelial, connective and muscle. Unlike plants, animals don't have cell walls; their cells may be embedded in extracellular matrices and possess unique structures for intercellular communication.
There are nerves and muscles in animals that provide coordination and movement; these are absent in plants and fungi. Animals also possess epithelial tissues, such as the epidermis, which function in secretion and protection. Animals are divided into two groups, the Parazoa (spines), which lack specialised tissues, and the Eumetazoa (all other animals).
4. In the event that animal classification is not based on common characteristics, what challenges would you encounter?
According to the known classification scheme of animals, they are grouped according to common characteristics, such as cell arrangement, body symmetry, type of coelom, digestive tract, circulatory system, or reproductive system. Therefore, if common features are not taken into account, classification would be difficult to
Analyse how various animals are connected
Tracing the interdependence between them
Identifying new animal species
In order to classify these animals, we must consider the various common fundamental characteristics. If this is not the case, it is impossible to deal with every living form separately at an individual level. Thus, it is necessary to base the classification on the same fundamental characteristics in order to study diversity properly.
5. Distinguish between intracellular and extracellular digestion?
Intracellular digestion
1. The digestive process occurs within food vacuoles within cells.
2. It is the food vacuole that secretes lysosomal enzymes
3. Products of digestion are diffused into the cytoplasm through the vacuolar membrane.
4. Ingestion occurs through pinocytic vesicles, like those found in protozoans, sponges, and coelenterates.
Extracellular Digestion
The digestive process occurs outside of cells in the alimentary canal.
Salivary, gastric pancreatic, and intestinal enzymes are secreted into the digestive cavity.
Digested food material is absorbed into the blood through gut epithelia.
6. What are the 12 main groups (phyla) of animals in the animal kingdom?
The animal kingdom is divided into different groups based on their body structure and features. The main phyla include Porifera (sponges), Cnidaria (jellyfish, corals), Platyhelminthes (flatworms), Nematoda (roundworms), Annelida (earthworms, leeches), Arthropoda (insects, crabs), Mollusca (snails, octopuses), and Echinodermata (starfish, sea urchins). Each group has unique characteristics that make them different from others.
7. Which is the biggest group of animals?
The largest group of animals is Arthropoda. It is the biggest phylum in the animal kingdom, making up about 84% of all known animal species. This group includes insects, spiders, crabs, and many more. Arthropods have jointed legs, a hard outer covering (exoskeleton), and segmented bodies.
8. How many types of animal groups (phyla) are there?
There are 36 known animal phyla, which are major groups used to classify animals. However, most living species belong to just nine main phyla, including Mollusca, Porifera, Cnidaria, Platyhelminthes, Nematoda, Annelida, Arthropoda, Echinodermata, and Chordata. These groups include everything from sponges and worms to insects, fish, and mammals.
9. Which is the rarest animal group (phylum)?
The rarest animal group is Phylum Loricifera. These tiny creatures were discovered in 1983 and are so rare that they don’t even have a common name. Unlike most animal groups named in the 18th and 19th centuries, Loriciferans were identified much later. They are found in deep-sea environments and remain one of the least studied animals.
10. What are the seven groups of living organisms?
Living organisms are classified into seven major groups based on their characteristics. These groups are-
Archaebacteria - Ancient bacteria found in extreme conditions.
Eubacteria - Common bacteria found everywhere.
Protista - Single-celled organisms like amoeba.
Chromista - Algae and other plant-like microorganisms.
Fungi - Mushrooms, moulds, and yeasts.
Plantae - All types of plants.
Animalia - All animals, from insects to humans.
