Performance Expectation 

Each standard contains a performance expectation that details how students can perform to show what they’ve learned. It describes what students should be able to do, as opposed to what they understand.

With MS-LS2-1, the first thing we need to consider is that this standard asks students to analyze and interpret data to provide evidence for the effects of resource availability on populations. The clarification statement specifies that we need to focus on cause and effect relationships between resources and the growth of individual organisms AND the numbers of organisms during periods of abundance or scarcity. 

The Three-Dimensions

1. The SEP for this performance expectation is Analyzing and Interpreting Data, and more specifically, students are asked to use the data they’re given to provide evidence on resource availability on individual organisms and populations of organisms in an ecosystem.
2. There are three elements of the DCIs. Students must explain that organisms are dependent on their interactions with
   living and nonliving factors in their environment. They also need to understand that limited resources or similar resource needs may drive competition between organisms and populations. Finally, students need to understand that resource availability can limit growth of organisms and populations. For example, cactus and other organisms must be opportunistic about water availability in the desert, using different mechanisms for absorbing water and maintaining internal hydration over long periods of time. This same lens can be applied in this standard to the entire population of cactus in an area and how water availability impacts the larger population, not just an individual organism. 
3. Finally, the Cross-Cutting Concept in this PE is cause and effect. Students must make connections from the data they’re looking at to provide evidence for cause and effect relationships between resource availability and changes in an organism or populations of organisms. 

The Goals

By the end of a unit or lesson on this standard, students should achieve the following milestones: 

1. 1. Understand that organisms interact with different parts of their environment. 
   2. Be able to read data on population changes or see patterns in an organism’s growth. 
   3. Use data to find patterns in changes in resource availability and the changes in population growth or organism growth. 
   4. Finally, students need to be able to cite evidence from data to explain causal relationships between resource availability and the growth of populations. 

An important piece to instruction and assessment on MS-LS2-1 is the phenomena we use to give students an opportunity to makes sense of these concepts. Let’s take cane toads in Australia as an example:

1. Give students a map of cane toads spread over an area in Australia over time. Ask, ” What do you notice and wonder about the spread of cane toads? How do you think this changes the environment for the animals and plants that lived there before?”
2. Students can then look at a specific data set of resources impacted by cane toads, or a simple gif of toads eating different things. We can ask, “What other organisms eat these things? What happens if the cane toads eat all of them?”
3. Lastly, we can give students a more complicated graph of cane toad populations in an area and the changing populations of different organisms. We can ask students, “How does the availability of resources in the area impact the changes in each of these populations?”

Student Activity

Once students understand the concept that resource availability impact population growth, we can give them opportunities where they need to make sense of a novel phenomenon. For example, they examine the impacts of deforestation on jaguar population density, specifically in Paraguay. 

Looking at the data sets in the above research studies and giving students some context on jaguar feeding and behavior, we can ask students to answer the following questions: “What resources do jaguars need to survive and grow? When forests are cut down, how does this impact their ability to thrive?” 

The final task, after the above scaffolding, could be for students to: Write a CER statement, citing data from the above tables and graphs to answer this question: “How does the availability of resources impact jaguar populations?”

The novelty of the above phenomena is an essential element of the sensemaking process. Students need to be examining a completely novel phenomena, where they can apply their understandings of resource availability on changing populations. At this point in your lessons or unit, students should’ve seen other examples of phenomena related to this standard in instruction and the jaguar phenomena should be completely novel to them.