Highlighted Phenomena from High School Life Science/Biology
- Skin cells are constantly dying, but we do not really notice because the new ones look identical to the old ones.
- A person’s internal temperature varies by only a few degrees even as the temperature outside spans as much as 40°C.
- There are many more deer than mountain lions in an ecosystem.
- Adenine and thymine are present in equal amounts in cells.
- Skin cancer is more common in people with a specific gene on chromosome 9.
- Several other species of hominin existed, but our species, homo sapiens, is the only one that survived to today.
Introduction to High School Life Science/Biology
The framework’s high school life science/biology section articulates the level of depth and complexity that the CA NGSS expect in high school. Compared to the middle grades, high school adds relatively few new concepts but instead provides a richer and deeper understanding of the topics that builds on students’ existing knowledge and abilities in all three dimensions of the CA NGSS. The biggest progression is the addition of DNA (middle grades DCIs refer to “genetic information” stored on chromosomes but middle grades students are not expected to be familiar with DNA). In high school, students revisit many of the same DCIs from the middle grades and ask, How does DNA act as a mechanism in this process? High school also assumes deeper engagement with the language of chemistry (especially as students discuss the mechanisms of photosynthesis, respiration, and protein synthesis) and tools of mathematics (e.g., probability in genetics and statistics of populations). High school students are also ready to address stability and change at a new level of sophistication (homeostasis in organisms and carrying capacity within ecosystems). Several activities engage students in algorithmic thinking and computational models of population dynamics.
The framework also provides examples of how engineering fits into a biology curriculum. In an engineering connection in IS5 (Cycles of Matter and Energy Transfer in Ecosystems), students play the role of wastewater engineers to optimize conditions for bacteria to speed up wastewater treatment. They use sugars to represent organic waste, yeast to represent the waste-processing bacteria, and glucose test strips to measure the concentration of waste in the water. Is there an optimal amount of yeast to add? Does the treatment process speed up or slow down when students add air or seal the container? What techniques can they develop for efficiently adding air? This engineering task aids students’ understanding of HS-LS-2.B so that they can explain the flow of matter and energy in aerobic and anaerobic conditions (HS-LS2-3), but it also ties strongly to the EP&Cs. In another engineering connection in IS12 (Adaptation and Biodiversity), students play the role of conservation biologists. They design a captive breeding system for California condors, using a computer simulation to determine how many breeding pairs they will need to support and how quickly they expect the population to recover.
The life science/biology course is divided into 12 instructional segments grouped into four sections. In the first section, From Molecules to Organisms: Structures and Processes, students develop models of how molecules combine to build cells and organisms (IS1 [Structure and Function]; IS2 [Growth and Development of Organisms]; IS3 [Organization for Matter and Energy Flow in Organisms]). In the second section, Ecosystems: Interactions, Energy, and Dynamics, students zoom out to the macroscopic scale to show how organisms interact (IS4 [Interdependent Relationships in Ecosystems]; IS5 [Cycles of Matter and Energy Transfer in Ecosystems]; IS6 [Ecosystem Dynamics, Functioning, and Resilience]; IS7 [Social Interactions and Group Behavior]). Students return to the role that DNA plays in inheritance during the third section, Heredity: Inheritance and Variation of Traits (IS8 [Inheritance of Traits]; IS9 [Variation of Traits]). The class ends tying together interactions at all these scales by explaining evolution and natural selection in Biological Evolution: Unity and Diversity (IS10 [Evidence of Common Ancestry and Diversity]; IS11 [Natural Selection]; IS12 [Adaptation and Biodiversity]). A vignette in IS12 illustrates the level of three-dimensional understanding students are expected to exhibit as a capstone of the course.
from d’Alessio, Matthew A. (2018). Executive Summary: Science Framework for California Public Schools: Kindergarten Through Grade Twelve. Sacramento: Consortium for the Implementation of the Common Core State Standards.