Exploring Ecosystems

All around the world, living things interact with the environment around them. These interactions create what scientists call an ecosystem. An ecosystem includes all the organisms living in an area and the nonliving parts of the environment they depend on. Ecosystems can be large, like an ocean, or small, like a pond or a forest clearing. No matter the size, every ecosystem is made up of many parts that work together.

In a pond ecosystem, many biotic and abiotic factors interact. Trees, birds, insects, mushrooms, and deer are some of the biotic factors living near the pond. These organisms depend on the abiotic parts of the environment to survive. Sunlight provides energy for plants to grow. The soil contains nutrients that help plants develop strong roots. Water from rain supports both plants and animals, and the temperature of the air affects how organisms live and grow.

Because biotic and abiotic factors are connected, a change in one part of the ecosystem can affect many others. For example, if there is less rainfall in the forest, plants may not grow as well. This could reduce the food available for insects and animals that depend on those plants. When all of these parts interact and influence one another, they form a complex and balanced ecosystem.

Directions: Read the passage below and then answer the questions.

Animal Interactions

In different ecosystems, organisms interact with one another in many ways to survive. These interactions can involve gaining food, protecting resources, or working together as a group.

In a grassy field, a fox patrols a specific area where it hunts for food. When another fox enters this space, the first fox chases it away and defends the area.

On the open plains, a herd of mustang ponies gathers near a watering hole. Not all of the ponies drink at the same time. Instead, there is a clear order, where certain members drink first while others wait their turn.

In the ocean, a group of dolphins works together to catch food. They swim in a circle around a school of mackerel, trapping the fish tightly together into what is called a bait ball, making it easier to catch them.

On the savanna, a female lioness comes across a carcass that a pack of hyenas is trying to claim. The lioness fights off the hyenas in order to gain access to the food.

Nearby, a cheetah spots a young gazelle. It quietly stalks its target before sprinting forward in an attempt to catch it for a meal.

Use the graph below to answer the attached questions:

Mice in the Wild

In a large grassy meadow, a population of mice lives among the tall plants and scattered bushes. At certain times of the year, the mice have plenty of food, such as seeds and insects, and many baby mice are born. As the number of mice increases, they begin to use up more of the available food and space.

With more mice living in the same area, it becomes harder for each one to find enough to eat. Some mice may not survive because they cannot find food or safe shelter. In addition, predators such as owls and snakes hunt the mice, and diseases can spread more easily when many mice live close together.

Over time, these factors balance out the number of mice being born with the number of mice that die. Even though individual mice are constantly being born and dying, the overall population size tends to stay about the same.

Use the table below to answer the questions: