Jessi and Squeaks are learning more about the redwoods, and all the different animals that live in the different layers! Second Grade Next Generation Science Standards Disciplinary Core Idea: LS4.D: Biodiversity and Humans - There are many different kinds of living things in any area, and they exist in different places on land and in water (2-LS4-1). Performance Expectation: 2-LS4-1. Make observations of plants and animals to compare the diversity of life in different habitats.