Unit Overview

The big picture stuff: Throughout elementary grades, students learned about external characteristics and adaptations of plants and animals as fundamental principles of physiology. In grade 5, they were introduced to particular chemical reactions, such as photosynthesis and cellular respiration, drive the physiological processes of living cells. In grade 6, they now start to put the pieces together to understand that organisms are key players in larger systems that interact and influence each other. Not only do individuals obtain and use matter and energy, but this same matter and energy moves through an ecosystem. Students can formulate an answer to the question, “How do organisms interact with other organisms in the physical environment to obtain matter and energy? Students can understand that organisms and populations of organisms are dependent on their environmental interactions both with other organisms and with nonliving factors. They also understand the limits of resources influence the growth of organisms and populations, which may result in competition for those limited resources.

Next Generation Science Standards – Middle School (NGSS-MS):

LS2-1. Analyze and interpret data to provide evidence for the effects of resource availability on organisms and populations of organisms in an ecosystem.

Emphasize: cause and effect relationships between resources and growth of individual organisms and the numbers of organisms in ecosystems during periods of abundant and scarce resources.

Core ideas: Ecosystems are dynamic in nature; their characteristics can vary over time. Disruptions to any physical or biological component of an ecosystem can lead to shifts in all its populations. Organisms, and populations of organisms, are dependent on their environmental interactions both with other living things and with nonliving factors. In any ecosystem, organisms and populations with similar requirements for food, water, oxygen, or other resources may compete with each other for limited resources, access to which consequently constrains their growth and reproduction. Growth of organisms and population increases are limited by access to resources.

LS2-2. Construct an explanation that predicts patterns of interactions among organisms across multiple ecosystems.

Emphasize: predicting consistent patterns of interactions in different ecosystems in terms of the relationships among and between organisms and abiotic components of ecosystems. Examples of types of interactions could include competitive, predatory, and mutually beneficial.

Core ideas: Predatory interactions may reduce the number of organisms or eliminate whole populations of organisms. Mutually beneficial interactions, in contrast, may become so interdependent that each organism requires the other for survival. Although the species involved in these competitive, predatory, and mutually beneficial interactions vary across ecosystems, the patterns of interactions of organisms with their environments, both living and nonliving, are shared.

LS2-3. Develop a model to describe the cycling of matter and flow of energy among living and nonliving parts of an ecosystem.

Emphasize: describing the conservation of matter and flow of energy into and out of various ecosystems, and on defining the boundaries of the system, not the use of chemical reactions to describe the processes.

Core ideas: Food webs are models that demonstrate how matter and energy is transferred between producers, consumers, and decomposers as the three groups interact within an ecosystem. Transfers of matter into and out of the physical environment occur at every level. Decomposers recycle nutrients from dead plant or animal matter back to the soil in terrestrial environments or to the water in aquatic environments. The atoms that make up the organisms in an ecosystem are cycled repeatedly between the living and nonliving parts of the ecosystem.

LS2-4. Construct an argument supported by empirical evidence that changes to physical or biological components of an ecosystem affect populations.

Emphasize: recognizing patterns in data and making warranted inferences about changes in populations, and on evaluating empirical evidence supporting arguments about changes to ecosystems.

LS2-5. Evaluate competing design solutions for maintaining biodiversity and ecosystem services.

Examples: water purification, nutrient recycling, and prevention of soil erosion. Design solution constraints could include scientific, economic, and social considerations.

Core ideas: Biodiversity describes the variety of species found in Earth’s terrestrial and oceanic ecosystems. The completeness or integrity of an ecosystem’s biodiversity is often used as a measure of its health. Changes in biodiversity can influence humans’ resources, such as food, energy, and medicines, as well as ecosystem services that humans rely on—for example, water purification and recycling.

ETS1-2: There are systematic processes for evaluating solutions with respect to how well they meet the criteria and constraints of the problem.

Science and Engineering:

• Construct an oral and written argument supported by empirical evidence and scientific reasoning to support or refute an explanation or a model for a phenomenon or a solution to a problem.
• Science disciplines share common rules of obtaining and evaluating empirical evidence.
• Develop a model to describe phenomena.
• Analyze and interpret data to provide evidence for phenomena.
• Construct an explanation that includes qualitative or quantitative relationships between variables that predict phenomena.
• Evaluate competing design solutions based on jointly developed and agreed-upon design criteria.

Crosscutting concepts:

• Cause and effect relationships may be used to predict phenomena in natural or designed systems.
• The transfer of energy can be tracked as energy flows through a natural system.
• Small changes in one part of a system might cause large changes in another part.
• Science assumes that objects and events in natural systems occur in consistent patterns that are understandable through measurement and observation.
• Patterns can be used to identify cause and effect relationships.
• Small changes in one part of a system might cause large changes in another part.
• The use of technologies and any limitations on their use are driven by individual or societal needs, desires, and values; by the findings of scientific research; and by differences in such factors as climate, natural resources, and economic conditions. Thus technology use varies from region to region and over time.
• Scientific knowledge can describes consequence of actions but does not make the decisions that society takes.

California Science Standards:

Life Science Standards:

5a. Students know energy entering ecosystems as sunlight is transferred by producers into chemical energy through photosynthesis and then from organism to organism through food webs.

5b. Students know matter is transferred over time from one organism to others in the food web and between organisms and the physical environment.

5c. Students know populations of organisms can be categorized by the functions they serve in an ecosystem.

5d. Students know different kinds of organisms may play similar ecological roles in similar biomes.

5e. Students know the number and types of organisms an ecosystem can support depends on the resources available and on abiotic factors, such as quantities of light and water, a range of temperatures, and soil composition.

Investigation and Experimentation Standards:

7a. Develop a hypothesis.

7b. Select and use appropriate tools and technology (including calculators, computers, balances, spring scales, microscopes, and binoculars) to perform tests, collect data, and display data.

7c. Construct appropriate graphs from data and develop qualitative statements about the relationships between variables.

7e. Recognize whether evidence is consistent with a proposed explanation.

7h. Identify changes in natural phenomena over time without manipulating the phenomena (e.g., a tree limb, a grove of trees, a stream, a hillslope).