Symmetry in biology
Videos
Symmetry in biology refers to the symmetry observed in organisms, including plants, animals, fungi, and bacteria. External symmetry can be easily seen by just looking at an organism. For example, the
A selection of animals showing a range of possible body symmetries, including asymmetry, radial, and bilateral body plans
Illustration depicting the difference between bilateral (Drosophila), radial (actinomorphic flowers) and spherical (coccus bacteria) symmetry
Lilium bulbiferum displays hexamerism with repeated parts arranged around the axis of the flower.
Apple cut horizontally showing that pentamerism also occurs in fruit
Echinoderm
Videos
An echinoderm is any animal of the phylum Echinodermata, which includes starfish, brittle stars, sea urchins, sand dollars and sea cucumbers, as well as the sessile sea lilies or "stone lilies". While
Symmetry in biology
…extending from the center of the oral surface, which contains the mouth, to the center of the opposite (aboral) end. Animals in the phyla Cnidaria and Echinodermata generally show radial symmetry, although many sea anemones and some corals within the Cnidaria have bilateral symmetry defined by a single structure…
Echinoderm collage 2
A brittle star, Ophionereis reticulata
A sea cucumber, Stichopus chloronotus, from Malaysia
Starfish of varied colours