An ecosystem consists of all the living and nonliving things in an area, connected as a dynamic and complex whole. Think about the types of plants that grow in calcium-rich soils on a shady slope or insects that we find living on the bottom of a slow moving stream. An ecosystem can be as vast as an ocean or as small as an isolated vernal pool. Studying an ecosystem means looking at how energy flows and matter recycles in the system.
For living things to survive, the environment in which they live, their habitat, needs to provide food, water, protection from enemies and weather, and places to raise young. Each species has its own particular needs and can live in some places but not in others.
We'll compare a variety of different ecosystems, consider the interactions we observe, and examine the animals and plants inhabiting each as we explore the out of doors. Throughout the year, students will examine the characteristics of organisms and consider the interconnections among living and non-living systems in the Earth's environments.
Descriptions of Topics
Signs of Leaf Eaters
By summer’s end, nearly every leaf bears some signs of feeding by plant-eaters small or large. Some make holes, some scallop the edges, and some roll the leaves into tubes. When we look closely, we may get to watch a leaf-eater feeding on a leaf – or being eaten by a predator – a real life look at the flow of energy from sun to plant to plant-eater to meat-eater. Here is evidence of a food chain, a component of every ecosystem. We'll learn what an ecosystem is, how the parts relate, and best of all, we'll take a minute to quietly sit and become part of this busy, buzzy world.
Life in the Dirt
Life abounds right under our feet, from plant roots to earthworms to moles and millipedes. All these dirt-dwelling organisms play important roles in the flow of energy and matter through an ecosystem. Many soil critters act as decomposers, breaking down plant and animal material and returning them as nutrients to the soil where other living things may use them again. We’ll get to know some dirt dwellers, and dig in to discover the amazing variety and complexity of life in the dirt.
Under the deep forest canopy, the forest floor hosts a wide variety of plants and animals that together form a complex food web and an efficient recycling system. Think about how deep the pile of leaves in a forest would be if it weren't for the important work of the decomposers. These busy organisms recycle nutrients, putting them back into the system for other living things to use to grow and thrive. We'll lie down and smell the leaf litter, look for decaying leaves, fungi, and insects, and imagine what it would be like to spend our lives on the forest floor.
Snags and Rotting Logs
The death of a tree opens up a whole new set of interactions in a forest. The standing snag serves as a home for a variety of fungi, lichen, insects, and other animals – birds nest in the branches, raccoons den in the rotting trunk. Once the snag topples over, the process of decomposition speeds up. A rotting log serves as a habitat for a parade of plants and animals, which change over time according to the log's stage of decomposition.
Amazing acrobats of the tree tops and phone wires, squirrels entertain us with their often nutty behavior. We’ll meet three kinds of squirrels - gray, red and flying squirrels - all of which occupy the forests of the northeast, often competing for the same foods and shelters. We’ll see how they each have a special niche – particular habits and habitat preferences – that helps them to live side by side. We’ll experience the nature of competition when we hide away nuts, and compare our success rate to squirrels when we attempt to retrieve our hidden caches.
Ecosystems are very different places in the winter, with less solar energy, shorter days, and little or no food-production by plants. And yet, many small, warm-blooded critters stay active throughout this coldest of seasons. How do active animals meet their energy needs in winter? Do fur, fat, and feathers help them retain heat? Can a blanket of icy snow provide protection as well? We'll compare the insulating properties of different materials as we consider how animals conserve energy to stay alive in winter.
White-tailed deer are among the largest herbivores in our forest ecosystems. We’ll consider their connections to the other plants and animals – the role deer play in the forest food web – and learn how living in a herd helps deer, even though group members may compete for food. We’ll examine the deer’s physical features – skull, legs, hoofs, fur – and think about how these help deer to find food and avoid predators. Finding sign of deer – tracks, browse, rubbings – may be the only way we know that this elusive creature lives in our neighborhood.
Water in a stream rushes, splashes, tumbles and flows smoothly, creating different conditions and homes for a variety of organisms. How do stream animals find food and shelter, and keep from getting swept away, in an ever-changing environment? What roles do they play in the stream ecosystem? Our stream study will include plenty of time to explore a stream and to examine the different animals that call this watery world their home.
More than just a collection of trees, a forest ecosystem is a complex interaction of sunlight and shadow, rain and wind, leafy canopy and shady under-story. Why do so many kinds of birds make forests their home in the summer, and how are they important to its health? We'll look at the different layers of plants in a forest and see how birds avoid competition by nesting and feeding in these different strata. We’ll learn how to recognize at a glance some of the illusive but vocal birds that make their homes in each.
Ponds contain a variety of different habitats: the surface film, the shoreline, the lake bottom and the open water. As we explore a pond we’ll meet a great variety of plants and animals living in these different zones. We’ll consider how they meet the challenges of life in still waters – finding food and hiding places, and, for those that live underwater, getting oxygen. With nets and buckets we’ll enjoy the sights and sounds of pond life as we get our feet wet and take a look.