Animals and Structures
This term describes animals that do NOT have a backbone
invertebrate
Symmetry where the body can be divided into equal halves along one plane (left and right).
bilateral symmetry
The group of animals that have jointed legs, segmented bodies, and an external skeleton.
arthropod
A major change in body form during an animal's life (example: caterpillar to butterfly).
metamorphosis
A group of marine animals with spiny skin and tube feet; many show radial symmetry as adults.
echinoderm
This term describes animals that HAVE a backbone
vertebrate
Symmetry where body parts are arranged around a central point, like a wheel.
radial symmetry
The hard outer covering that protects an arthropod and must be shed for the animal to grow.
exoskeleton
A worm group with segments in their bodies (example: earthworms).
annelids
Soft-bodied animals, often with a hard shell (examples: snails, clams, octopus).
mollusk
A small, hard support structure found in some sponges that helps keep them rigid.
spicule
An animal that feeds by straining tiny particles or organisms from water
filter feeder
To shed an old exoskeleton so the animal can grow a bigger one
molting
An animal that has six legs and three body sections (head, thorax, abdomen).
insect
Crustaceans like crabs and shrimp belong to this larger group with jointed legs.
arthropod
A stinging cell used by jellyfish and other cnidarians to capture prey
nematocyst
A living strategy where an animal lives independently, not relying on a host
free-living
A group of arthropods with two main body segments, eight legs, and no antennae
arachnid
An animal that lives by feeding on other organisms but does not necessarily live inside a host (contrast with parasite).
free-living
A hard external structure crustaceans use for protection; often must be shed for growth.
exoskeleton
An organism that lives on or in a host and may harm it while benefiting itself.
parasite
Tiny bristle-like structures on some worms that help them move or grip surfaces.
setae
A mainly aquatic group of arthropods that usually have gills and many limbs, like crabs and shrimp.
crustacean
What are the stages of complete and incomplete metamorphosis?
Complete: egg, larva, pupa, adult
Incomplete: egg, nymph, adult
Name two major differences between echinoderms and mollusks
(1) echinoderms usually have radial symmetry and tube feet, while mollusks often have bilateral symmetry and a muscular foot;
(2) echinoderms have spiny skin, mollusks often have shells?