© William C. Ratcliff 2013 Alignment of our curriculum to NGSS standards “From viruses and bacteria to plants to fungi to animals, the diversity of the millions of life forms on Earth is astonishing. Without unifying principles, it would be difficult to make sense of the living world and apply those understandings to solving problems. A core principle of the life sciences is that all organisms are related by evolution and that evolutionary processes have led to the tremendous diversity of the biosphere. There is diversity within species as well as between species. Yet what is learned about the function of a gene or a cell or a process in one organism is relevant to other organisms because of their ecological interactions and evolutionary relatedness. Evolution and its underlying genetic mechanisms of inheritance and variability are key to understanding both the unity and the diversity of life on Earth.” Quinn et al, 2011 Our labs are aligned with the Next Generation Science Standards, a set of cutting-edge standards developed by 26 states. This lab is ideally suited for implementation in an NGSS-aligned curriculum. The NGSS standards are based on three key dimensions: practices, cross-cutting concepts, and disciplinary core ideas. These lab integrate these three dimensions. By generating hypotheses and testing them experimentally through inquiry-based approaches, students are immersed in the practice of science. Cross- cutting concepts (e.g., using logic to make inference, cause and effect) are utilized throughout the labs. Perhaps more importantly, the lab teaches students key concepts from all four core ideas in the life sciences (see below). Core idea LS1 The first core idea, LS1: From Molecules to Organisms: Structures and Processes, addresses how individual organisms are configured and how these structures function to support life, growth, behavior, and reproduction. The first core idea hinges on the unifying principle that cells are the basic unit of life.1 Lab applications That cells are the “basic unit of life” is one of the core lessons of this lab. By evolving multicellular individuals from unicellular ancestors and thinking deeply about the nature of biological individuality, students are given many opportunities to absorb the importance of cells to life as we know it. Further, the lab has students think about the evolutionary origins of cellular division of labor, both in terms of process (multilevel selection and the transition to multicellularity) and ecology (benefits/costs). Core idea LS2 The second core idea, LS2: Ecosystems: Interactions, Energy, and Dynamics, explores organisms’ interactions with each other and their physical environment. This includes how organisms obtain resources, how they change their environment, how changing environmental factors affect organisms and ecosystems, how social interactions and group behavior play out within and between species, and how these factors all combine to determine ecosystem functioning.1 Lab applications Students will examine how ecology and evolution interact. Specifically, they will examine how selection for rapid settling through liquid media can result in the evolution of multicellularity. Next, they will measure the strength of selection by rotifer predators on yeast body size. Multicellularity is an inherently social activity- formerly autonomous cells (organisms in their own right) band together and form a new, higher-level organism. This creates many new among-cell social interactions, and the potential for the evolution of new cooperative behaviors (e.g., cellular division of labor). Core idea LS3 The third core idea, LS3: Heredity: Inheritance and Variation of Traits across generations, focuses on the flow of genetic information between generations. This idea explains the mechanisms of genetic inheritance and describes the environmental and genetic causes of gene mutation and the alteration of gene expression.1 Lab applications Students will examine the reproductive mode of both unicellular and multicellular yeast. Inheritance and transmission of cluster-level traits is a central part of this lab. While examining the genetic basis of variation in snowflake yeast life history traits is beyond the scope of this lab, the Ratcliff and Travisano labs are pursuing genetic lines of inquiry, and motivated students can read these scientific papers. Core idea LS4 “The fourth core idea, LS4: Biological Evolution: Unity and Diversity, explores changes in the traits of populations of organisms over time and the factors that account for species’ unity and diversity alike. The section begins with a discussion of the converging evidence for shared ancestry that has emerged from a variety of sources (e.g., comparative anatomy and embryology, molecular biology and genetics). It describes how variation of genetically determined traits in a population may give some members a reproductive advantage in a given environment. This natural selection can lead to adaptation, that is, to a distribution of traits in the population that is matched to and can change with environmental conditions. Such adaptations can eventually lead to the development of separate species in separated populations. Finally, the idea describes the factors, including human activity, that affect biodiversity in an ecosystem, and the value of biodiversity in ecosystem resilience.1 Lab applications Students will examine the process of both micro and macroevolution. The evolution of multicellularity, a macroevolutionary step, results directly from straightforward microevolutionary processes (e.g., formation of snowflake yeast by daughter cell adhesion to mother cells). This lab examines the evolution of multicellularity through a multilevel selection lens. During the transition to multicellularity, selection shifts from single cells to whole clusters. If clusters possess heritable variation for cluster level traits that affect fitness, then selection among clusters will result in cluster-level adaptation. This is the standard Darwinian process, but applied at a higher level in the biological hierarchy. All quotes above are are taken from: 1. Quinn, Helen, Heidi Schweingruber, and Thomas Keller, eds. A framework for K-12 science education: Practices, crosscutting concepts, and core ideas. National Academies Press, 2011.   Standards Alignment Next Generation Science Standards