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Classification of Living Things

10 min read

Kingdom Animalia

Animals are multicellular organisms that eat other organisms (heterotrophs), have no cell walls or chloroplasts, and usually move. The kingdom is divided into phyla. A big division is between invertebrates, animals without a backbone, and vertebrates, animals with a backbone.

The five kingdomsFive coloured boxes naming the five kingdoms of living things with an example of each: Monera such as bacteria, Protoctista such as amoeba and algae, Fungi such as mushrooms and yeast, Plantae such as maize, and Animalia such as fish, birds and humans.MonerabacteriaProtoctistaamoeba, algaeFungimushroom, yeastPlantaemaize, mango treeAnimaliafish, bird, humanLiving things are sorted into five kingdoms
PhylumMain featuresExamples
PoriferaBody with many pores, no organsSponges
CnidariaStinging cells, two cell layersJellyfish, sea anemone
PlatyhelminthesFlat body, no segmentsTapeworm, flatworm
NematodaRound, unsegmented wormsHookworm, roundworm
AnnelidaSegmented bodyEarthworm, leech
MolluscaSoft body, often a shellSnail, octopus
ArthropodaJointed legs, exoskeletonInsects, spiders, crabs
ChordataBackbone (vertebrates)Fish, birds, mammals

Arthropod classes

ClassLegsBody partsExample
Insecta63 (head, thorax, abdomen)Housefly, bee
Arachnida82Spider, scorpion
Crustacea10 or more2Crab, prawn
MyriapodaManyManyCentipede, millipede

The vertebrate classes

Classes of vertebratesFive tiles for the vertebrate classes. Fish have scales, gills and fins and lay eggs in water. Amphibians have moist skin and live in water and on land. Reptiles have dry scaly skin and lay leathery eggs. Birds have feathers, wings and lay hard-shelled eggs. Mammals have hair, make milk and most give birth to live young.Fishscalesgills, finscold-bloodedeggs in waterAmphibiansmoist skinlungs and skincold-bloodedeggs in waterReptilesdry scaleslungscold-bloodedleathery eggsBirdsfeatherswings, beakwarm-bloodedhard-shelled eggsMammalshair or furmammary glandswarm-bloodedlive young
Try itIs it an insect?

Choose the number of legs of an arthropod to find its class.

Check yourself How many legs has an insect?
Check yourself Which is a vertebrate with moist skin that lives on land and in water?
Check yourself Which phylum has jointed legs and an exoskeleton?

Key terms

Invertebrate
An animal without a backbone.
Vertebrate
An animal with a backbone.
Exoskeleton
A hard covering outside the body.
Phylum
A major group in the classification of animals.

Summary

  • Animals are multicellular heterotrophs without cell walls.
  • Invertebrate phyla include sponges, worms, molluscs and arthropods.
  • Insects have six legs and three body parts.
  • Vertebrate classes: fish, amphibians, reptiles, birds and mammals.
Genetics Evolution