Earth is home to countless organisms that look and live in different ways.
We sort them into five kingdoms—animals, plants, fungi, protists, and bacteria—and ranks narrow from kingdom to species.
Vertebrates split into fish, amphibians, reptiles, birds, and mammals, with traits like body-temperature control.
Tap the kingdom buttons and follow the ranks and vertebrate table to organize biodiversity.
How Are Organisms Classified?
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Five-kingdom system — life sorted into five major groups
💡 Five Kingdoms
①Animalia: moves on its own, eats other organisms
②Plantae: makes food via photosynthesis
③Fungi: reproduces by spores, acts as decomposer (mushrooms, molds)
④Protista: single-celled or simple multicellular (amoeba)
⑤Monera: single-celled organisms without a nucleus (prokaryotes)
Levels of Classification
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Kingdom → Phylum → Class → Order → Family → Genus → Species
Classification Levels
Kingdom → Phylum → Class → Order → Family → Genus → Species
③Species criterion: can interbreed and produce fertile offspring
④Cold- vs warm-blooded: body-temperature regulation
⑤Why preserve biodiversity: ecosystem stability, medicine and food resources
Examples and Unit Test
Example 1
Among the five kingdoms, which group makes its own food by photosynthesis, and which group reproduces by spores as a decomposer like mushrooms and molds?
1
The five kingdoms are Animalia, Plantae, Fungi, Protista, and Bacteria (prokaryotes).
2
The group that makes food by photosynthesis is Plantae, and the group that reproduces by spores and acts as a decomposer is Fungi.
▸ Plantae / Fungi
The five kingdoms are divided by observable features such as photosynthesis, movement, and cell traits.
Example 2
In the classification ranks kingdom → phylum → class → order → family → genus → species, which rank is the broadest and which is the narrowest?
1
The ranks are broader toward the top and group more similar organisms in a narrower range toward the bottom.
2
So the broadest rank is kingdom and the narrowest is species.
▸ Broadest = kingdom / narrowest = species
Kingdom is broadest and species is narrowest; toward the bottom, organisms with more similar features are grouped.
Unit-test style
Which statement about classifying organisms is correct?
①Plantae gets its food by eating other organisms
②In the ranks, species is a narrower range than kingdom
③Fungi make food by photosynthesis
④Bacteria are made of cells that have a nucleus
⑤In the ranks, species is the broadest range
▸ ② In the ranks, species is a narrower range than kingdom
1
Kingdom is the broadest rank and species the narrowest, so species is a narrower range than kingdom.
2
Plantae makes food by photosynthesis (①), Fungi are decomposers, not photosynthetic (③), bacteria are prokaryotes without a nucleus (④), and kingdom is the broadest rank (⑤).