Page 10 - Science Course 2 (Book 1)
P. 10
Mo1-L1a: How are Animals Classified?
Key Concept
How are Animals Classified? • Animals that do not have bilateral symmetry or radial
symmetry have asymmetry, meaning they cannot be
What characteristics are common to all animals? divided into any two parts that are nearly mirror
images.
Scientists use a system called taxonomy to
organize living things.
The biggest groups in taxonomy are called domains.
The next level consists of the kingdom taxons.
How do scientists group animals?
Life
One way to group animals is by their symmetry, or
how body parts are arranged.
Domain
• Some animals have bilateral symmetry, a body
plan in which an organism can be divided into two
part that are nearly mirror images of each other. Kingdom
Phylum
Class
Order
• An animal with radial symmetry can be divided
into two parts that are nearly mirror images of each
other anywhere through its central axis. Family
Genus
Species
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