Biology basics & diversity of life · Topic 2 of 17

Classification & the Kingdoms of Life

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Biology · classification

Life is sorted from domain down to species, named with a two-part Genus species name, and split into three domains and six kingdoms.

01 · RanksDomain → kingdom → phylum … genus → species

02 · NamingGenus species: Genus capitalized, italic

03 · Domains3 domains: Bacteria, Archaea, Eukarya

3 domains: Bacteria, Archaea (prokaryotes) and Eukarya (cells with a nucleus) must know

Lower ranks hold fewer organisms that are more closely related

Carl Linnaeus built the ranked system and the two-part name

6 kingdoms: archaebacteria, eubacteria, protists, fungi, plants, animals

Classification now uses DNA/RNA comparisons, not just appearance

Species = organisms that can interbreed and have viable offspring

Bacteria: single-celled prokaryotes with peptidoglycan cell walls

Archaea: prokaryotes without peptidoglycan; many live in extreme places

Protists: mostly single-celled eukaryotes — the catch-all kingdom

Fungi: chitin cell walls; digest food outside, absorb it; decomposers

Plants: multicellular photosynthesizers with cellulose cell walls

Animals: multicellular, ingest food, no cell walls, mostly mobile

Domain → kingdom → phylum → class → order → family → genus → species

Binomial name = Genus species: genus capitalized, species lowercase, both italic must know

Commonly confused

	Fungi	Plants
Food	Heterotroph: absorbs digested food	Autotroph: photosynthesis
Cell wall	Chitin	Cellulose
Chloroplasts	None	Yes
Body	Single-celled yeasts to mushrooms	Multicellular

Fungi are not plants: no photosynthesis, chitin walls, closer kin to animals

"(Dear) King Philip Came Over For Great Spaghetti" = (D)-K-P-C-O-F-G-S

Show 3 more facts

Shortened form after first use: E. coli

Taxon = the named group at any rank

Viruses belong to no domain (not considered alive)

Pearl

Dear King Philip Came Over For Great Spaghetti: domain, kingdom, phylum, class, order, family, genus, species.

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