Summary
Animals show radial, bilateral or no symmetry, which relates to their lifestyle and movement.
In depth
Radial symmetry (cnidarians, adult echinoderms) suits sessile or drifting animals sensing from all sides; bilateral symmetry allows cephalisation (concentrated head and sensory organs) and directed movement. Asymmetry is seen in sponges.
Bilateral symmetry allows directional movement and head development. Radial symmetry suits sessile life. Spherical symmetry occurs in some protozoa.
Example: starfish adults are radial, larvae bilateral.
Frequently asked questions
What is Animal Symmetry?
Animals show radial, bilateral or no symmetry, which relates to their lifestyle and movement.
Which area of biology covers Animal Symmetry, and how advanced is it?
Animal Symmetry is one of the 53 topics in Zoology & Animal Diversity. It is rated Intermediate, so it suits learners who already know the core vocabulary. Related topics in this area include Echinoderms, Animal Kingdom, Germ Layers.
Can you give an example of Animal Symmetry?
Flatfish larvae are bilateral but adults become asymmetric.
What should I learn before Animal Symmetry?
Work through the Beginner topics in Zoology & Animal Diversity first, such as Animal Kingdom, Vertebrates and Invertebrates, Sponges, then return to Animal Symmetry. Intermediate topics assume the Beginner vocabulary.
What topics are related to Animal Symmetry?
The closest topics to Animal Symmetry are Echinoderms, Animal Kingdom, Germ Layers, Protostomes and Deuterostomes. Comparing them side by side is a good way to see how the ideas connect.
How can I check that I understand Animal Symmetry?
Read the summary and the in-depth section, then use the quick check on the interactive lesson for Animal Symmetry. To practise the whole of Zoology & Animal Diversity, use the Zoology & Animal Diversity quiz.
How is Animal Symmetry different from Echinoderms?
Animal Symmetry: Animals show radial, bilateral or no symmetry, which relates to their lifestyle and movement. Echinoderms: Marine animals with radial symmetry as adults and a water vascular system, like starfish. Read both side by side and note what each one explains.
How should I study Animal Symmetry step by step?
First, read the summary and write the definition in your own words. Second, read the in-depth section and note any example. Third, compare it with Echinoderms and explain the difference aloud. Finally, take the Zoology & Animal Diversity quiz and come back to this page for any question you miss.