Chapter 26: Sponges and Cnidaries / Chapter 27: Worms and Mollusks Flashcards
Animal that has a vertebral column, or backbone
Vertebrate
Animal that does not have a backbone, or vertebral column
Invertebrate
Innermost germ layer of most animals; develops into the linings of the digestive track and much of the respiratory system
Endoderm
Middle germ layer of most animals; gives rise to muscles and much of the circulatory, reproductive, and excretory systems
Mesoderm
Animal that relies on interactions with the environment to help it control body temperature
Ectoderm
Body plan in which body parts repeat around the center of the body; characteristic of sea anemones and sea stars
Radial Symmetry
Body plan in which only a single, imaginary line can divide the body into two equal halves; characteristic of worms, arthropods, and chordates
Bilateral Symmetry
Concentration of sense organs and nerve cells at the front of an animal’s body
Cephalization
Individual that has both male and female reproductive organs
Hermaphrodite
Head of an adult tapeworm; can contain suckers or hooks
Scolex
One of the segments that make up most of a tapeworms’s body
Proglottid
Band of thickened, specialized segments or annelids that secretes a mucous ring into which eggs and sperm are released
Clitellum
System in which blood is not always contained within a network of blood vessels
Open Circulatory System