Discuss the evolutionary adaptations that have enabled various groups of invertebrates to survive and thrive in extreme environments such as deep-sea hydrothermal vents, arid deserts, and polar regions. In your answer, include specific examples from at least three distinct invertebrate phyla. Describe the physiological, morphological, and behavioral adaptations that these organisms have developed. Additionally, explain how these adaptations contribute to their ecological roles and the stability of their respective ecosystems.