Living Things and the Environment
a. Organisms fulfill basic needs (food, water, shelter, and other life needs) from environment
b. One area may contain many habitats
c. Organisms live in different habitats because they have different requirements for survival
II. Biotic Factors
a. An organism interacts with both the living and nonliving parts of its habitat
b. The living parts of a habitat are called biotic factors
III. Abiotic Factors
1. All living things require water to carry out their life processes
2. Photosynthesis is the process by which plants make their own food using sunlight and water. Other animals depend on plants for food.
1. Sunlight is needed for photosynthesis
2. Most organisms cannot live in places without sunlight, as plants cannot grow there
1. Most living things require oxygen to carry out their life processes
2. Land organisms obtain oxygen from the air. Aquatic organisms obtain oxygen dissolved in water.
1. The temperatures that are typical of an area determine the types of organisms that can live there.
2. Some animals alter their environments so they can survive very hot or very cold temperatures.
1. Soil is a mixture of rock fragments, nutrients, air, water, and the decaying remains of living things.
2. The type of soil in an area influences the kinds of plants that can grow there.
IV. Levels of Organization
1. A species is a group of organisms that are physically similar and can mate with each other and produce offspring that can also mate and reproduce.
2. All the members of one species in a particular area are referred to as a population.
1. All the different populations that live together in an area make up a community.
2. To be considered a community, the different populations must live close enough together to interact.
1. The community of organisms that live in a particular area, along with their nonliving surroundings, make up an ecosystem.