Figure 2. Different members of Echinodermata include the (a) sea star of class Asteroidea, (b) the brittle star of class Ophiuroidea, (c) the sea urchins of class Echinoidea, (d) the sea lilies belonging to class Crinoidea, and (d) sea cucumbers, representing class Holothuroidea. Adapted from Holt Biology 2008 Chapter 17 Section 2: Genetic Change Key Vocabulary Terms . Adapted from Holt Biology 2008 Genetic Equilibrium A state in which the Biology 211 (2) Week 3!! Last of Chapter 30! VOCABULARY: !! KEY CONCEPTS:! 1. Describe the two generations in the Alteration of Generations. a. 1 diploid generation with sporophytes (2n) and spores, followed by 1 haploid generation with gametophytes (n) and gametes 2. Why is a plasmodial slime mold considered a coenocytic mass? What type of Start studying Biology Chapter 2. Learn vocabulary, terms, and more with flashcards, games, and other study tools.