Ecosystems

Discovering Connections in the Natural World

Living things are connected to each other and to their environment in many fascinating ways. In a sunny field, grasses, clover, and goldenrod capture sunlight to make food by photosynthesis. Rabbits and grasshoppers feed on leaves and shoots, and foxes feed on rabbits and grasshoppers. The wind scatters grass pollen and milkweed seeds, rainfall brings water, and worms turn dead leaves into soil underfoot. These are examples of the many interactions between plants and animals, sunlight, water, and air that go on in a field. Every different environment – field or forest, pond or stream – functions as an ecological system, or “ecosystem.” An ecosystem consists of all the living and nonliving things in a particular place and the ways they are connected. All the organisms in an ecosystem depend on everything else – both living and nonliving – for food and other needs. When we study ecosystems, we’ll consider how energy flows from sun to plants to animals, how plants and animals are linked in a food web, and how matter cycles through organisms and back into the soil.

In these units we’ll meet some animals and plants that are part of different ecosystems and consider the interactions we observe as we explore the out-of-doors. In doing so, we’ll learn about various ecological concepts. Signs of Leaf-eaters introduces the idea of a food web and the energy flow from sun to plants to animals. In Leaf Litter and Life in the Dirt we’ll learn about decomposition, how nutrients are returned to the soil where they can be used again by other living things. Snags and Logs explores the many roles of dead or dying wood in a forest and the concept of ecological succession, how plant and animal communities change over time.

Comparing the habits of the different kinds of squirrels that live in our forests, Squirrel Tales introduces the idea of a “niche” – how each squirrel has its particular food and habitat preferences, which helps reduce competition. Staying Warm looks at how energy flow slows down in winter when plants aren’t producing food. Animals must conserve energy or live on stored energy, whether they hibernate or stay active all winter long. White-tailed Deer considers the balance between the resources in a place and the number of animals it can support. We look at how deer play many roles in the forest ecosystem, and how predator and prey interactions affect how each evolves over time. In Forest Birds we wonder why so many birds come to our Northern forests to breed. We learn about the bountiful insects that provide them an energy-rich diet, how birds divide up the resources by occupying different layers of the forest, and how they enhance the health of a forest by keeping the many leaf-eating insects in check.

Stream Life and Pond Life look at how the varied physical conditions along a stream (riffle, pool, run, shaded, sunny, gravelly, sandy) or in a pond (shoreline, surface, open water, littoral zone) provide habitats for a great variety of small creatures. We learn about how aquatic organisms meet the challenges of finding food, avoiding predators, and breathing – all in and under the water. Here we look closely at the links between the living and the nonliving as we consider how a pond or stream ecosystem works.

As we explore the world outside the classroom doors, we’ll examine the characteristics of organisms and consider the interconnections among living and nonliving systems in the Earth’s environments, recognizing our own role as part of the ecosystem as well.

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Next Generation Science Standards and Common Core State Standards

The units and activities in Ecosystems support the three Dimensions of the Next Generation Science Standards.  Together the lessons in this concept give children opportunities to engage in the Science and Engineering Practices (Dimension I) and to reflect on the Cross-cutting Concepts (Dimension II) as identified in the Next Generation Science Standards. The monthly topics also address Disciplinary Core Ideas (Dimension III) in Physical Sciences (PS3: Energy), Life Sciences (LS1: From Molecules to Organisms: Structures and Processes, LS2: Ecosystems: Interactions, Energy, and Dynamics, LS3: Heredity: Inheritance and Variation of Traits, and LS4: Biological Evolution: Unity and Diversity) and Earth and Space Sciences (ESS2: Earth’s Systems). The specific Disciplinary Core Ideas that each lesson addresses are outlined in detail on the “Teacher Resources” page and the “Unit Summary” that accompany each unit.

In addition, each lesson supports aspects of both the English Language Arts and Math Common Core State Standards, including Reading for Informational Texts, Speaking and Listening, and Writing, as well as Counting, Operations, Measurement, and Data.