Living Things and the Environment Seventh Grade Chapter 22-1

Ecosystems All the living and nonliving things that interact in a particular area make up an ecosystem. Some examples of ecosystems are mountains, oceans, desserts, and forests.

Habitats A habitat is a specific place in an ecosystem where an organism obtains food, water, shelter, and other things it needs to live, grow, and reproduce. A single ecosystem may contain many habitats.

Habitats cont. Some examples of habitats in a forest ecosystem are plants growing in the damp soil, bears on the forest floor, and birds in nests at the top of a tree. Organisms live in different habitats because they have different requirements for survival

Biotic and Abiotic Factors The living things of an ecosystem are called biotic factors. Examples: - grass, plants, hawks, badgers, worms, fungi, and bacteria that all live in the same ecosystem The nonliving things in an ecosystem are called abiotic factors. Examples: - water sunlight, oxygen, temperature, and soil.

Water Water is very important to all organisms. The human body is made up of about 65% water. Plants and algae use water, along with sunlight and carbon dioxide, to make food in a process called photosynthesis.

Sunlight and Oxygen Sunlight is necessary for photosynthesis which is important because without plants or algae to provide a source of food, few other organisms would live. Most living things require oxygen to carry out their life processes. Organisms on land obtain their oxygen from the air while fish and other water organisms obtain dissolved oxygen from the water.

Temperatures and Soil Temperatures that are typical of an area determine what can live there. Some animals alter their environments to overcome very hot or very cold temperatures. The type of soil in an area influences the kinds of plants that can grow there. Some organisms make their homes in the soil.

Population All the members of one species in a particular area are referred to as a population. Studying the population is hard to do without a specified area. Ex. (Charlotte County)

Community All the different populations that live together in an area make up a community. In a community the different populations must live close enough together to interact with one another. They interact by using the same resources, such as, food and shelter.

Levels of Organization The smallest unit of organization is a single organism, which belongs to a population of other members of its species. The population belongs to a community of different species. The community and abiotic factors together form an ecosystem.

Ecology The study of how living things interact with one another and with their environment is called ecology. Ecologists study how organisms react to changes in their environment.