- Organisms are classified into groups based on how closely related they are to one another.
- All living thing are divided into five kingdoms
- Fungi are saprophytes (they feed of dead organisms and decaying material). They are multicellular and have a cell wall but don't have a chlorophyll.
- Animals are heterotrophs. They are multicellular but they don't have a cell wall or chlorophyll.
- Protocists e.g. algae
- Protocists are unicellular and have a nucleus.
- Plants contain chlorophyll and are autotrophs. They are multicellular and have rigid cell walls.
- Prokaryotes e.g. bacteria
- Prokaryotes are unicellular but they don't have a nucleus.
- Scientists divide vertebrates into these classes based on three things:
- 2. How they reproduce - external (e.g. fish) or internal fertilisation. Also whether they are oviparous (lay eggs e.g. reptiles), or viviparous (give birth to live young e.g. mammals)
- 1. How they absorb oxygen - through lungs (e.g. mammals), gills (e.g. fish) or skin (e.g. amphibians)
- 3. How they regulate their body temperature - homotherms (body temperature is regulatied by homeostatis e.g. mammals) or pokilotherms (body temperature changes with external temperature e.g. reptiles)
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