WA.4. Life Science
LS1. Structure and Function of Living Organisms
6-8.LS1. From Cells to Organisms: In prior grades students learned how structures in the body work together to respond to internal and external needs. In grades 6-8 students learn that all living systems are composed of cells which make up tissues, organs, and organ systems. At each level of organization, the structures enable specific functions required by the organism. Lifestyle choices and environmental conditions can affect parts of the human body, which may affect the health of the body as a whole. Understanding how organisms operate as systems helps students understand the commonalities among life forms, provides an introduction to further study of biology, and offers scientific insights into the ways that personal choices may affect health.
6-8.LS1A. Students know that all organisms are composed of cells, which carry on the many functions needed to sustain life.
6-8.LS1A.2. Students are expected to describe the functions performed by cells to sustain a living organism (e.g., division to produce more cells, taking in nutrients, releasing waste, using energy to do work, and producing materials the organism needs).
6-8.LS1B. Students know that one-celled organisms must contain parts to carry out all life functions.
6-8.LS1B.1. Students are expected to draw and describe observations made with a microscope showing that a single-celled organism (e.g., paramecium) contains parts used for all life functions.
6-8.LS1D. Students know that both plant and animal cells must carry on life functions, so they have parts in common, such as nuclei, cytoplasm, cell membranes, and mitochondria. But plants have specialized cell parts, such as chloroplasts for photosynthesis and cell walls, which provide plants their overall structure.
6-8.LS1D.1. Students are expected to use labeled diagrams or models to illustrate similarities and differences between plant and animal cell structures and describe their functions (e.g., both have nuclei, cytoplasm, cell membranes, and mitochondria, while only plants have chloroplasts and cell walls).
6-8.LS1E. Students know that in classifying organisms, scientists consider both internal and external structures and behaviors.
6-8.LS1E.1. Students are expected to use a classification key to identify organisms, noting use of both internal and external structures as well as behaviors.
6-8.LS2. Flow of Energy Through Ecosystems: In prior grades students learned how ecosystems change and how these changes affect the capacity of an ecosystem to support populations. In grades 6-8 students learn to apply key concepts about ecosystems to understand the interactions among organisms and the nonliving environment. Essential concepts include the process of photosynthesis used by plants to transform the energy of sunlight into food energy, which is used by other organisms, and possible causes of environmental change. Students also learn to investigate environmental issues and to use science to evaluate different solutions to problems. Knowledge of how energy flows through ecosystems is a critical aspect of students' understanding of how energy sustains life on the planet, including human life.
6-8.LS2B. Students know that energy flows through an ecosystem from producers (plants) to consumers to decomposers. These relationships can be shown for specific populations in a food web.
6-8.LS2B.1. Students are expected to analyze the flow of energy in a local ecosystem, and draw a labeled food web showing the relationships among all of the ecosystem's plant and animal populations.
6-8.LS2C. Students know that the major source of energy for ecosystems on Earth's surface is sunlight. Producers transform the energy of sunlight into the chemical energy of food through photosynthesis. This food energy is used by plants, and all other organisms to carry on life processes. Nearly all organisms on the surface of Earth depend on this energy source.
6-8.LS2C.1. Students are expected to explain how energy from the Sun is transformed through photosynthesis to produce chemical energy in food.
6-8.LS2C.2. Students are expected to explain that producers are the only organisms that make their own food. Animals cannot survive without producers because animals get food by eating producers or other animals that eat producers.
LS3. Biological Evolution
6-8.LS3. Inheritance, Variation, and Adaptation: In prior years, students learned that differences in inherited characteristics might help organisms survive and reproduce. In grades 6-8 students learn how the traits of organisms are passed on through the transfer of genetic information during reproduction and how inherited variations can become adaptations to a changing environment. Sexual reproduction produces variations because genes are inherited from two parents. Variations can be either physical or behavioral, and some have adaptive value in a changing environment. In the theory of biological evolution the processes of inheritance, variation, and adaptation explain both the diversity and unity of all life.
6-8.LS3A. Students know that the scientific theory of evolution underlies the study of biology and explains both the diversity of life on Earth and similarities of all organisms at the chemical, cellular, and molecular level. Evolution is supported by multiple forms of scientific evidence.
6-8.LS3A.1. Students are expected to explain and provide evidence of how biological evolution accounts for the diversity of species on Earth today.
6-8.LS3G. Students know that evidence for evolution includes similarities among anatomical and cell structures, and patterns of development make it possible to infer degree of relatedness among organisms.
6-8.LS3G.1. Students are expected to infer the degree of relatedness of two species, given diagrams of anatomical features of the two species (e.g., chicken wing, whale flipper, human hand, bee leg).