Content Vocabulary LESSON 1 Directions: Write the correct term in the boxes to the right of each clue. Then unscramble the letters in the shaded boxes to spell an eighth term. abiotic factor atmosphere biotic factor community ecosystem habitat population population density 1. all of the ants in a park, for example 2. 1 deer 2, for example 8,000 m 3. sunlight or water, for example 4. consists of multiple populations 5. made up of the main components of nitrogen, oxygen, and carbon dioxide 6. a tree or a dead organism, for example 7. includes all of the living and nonliving parts of the environment in an area 8. When unscrambled, the letters in the shaded boxes spell, which is the place where an organism lives. Interactions of Life 9
Lesson Outline LESSON 1 A. What is an ecosystem? 1. All the living things and nonliving things in a given area form a(n). 2. factors are the nonliving parts of an ecosystem; they provide that organisms need to survive and reproduce. a. Sunlight is an important factor because it supplies production of. b. Sunlight also provides warmth affecting an ecosystem s. for photosynthesis; this process results in the c. The atmosphere includes that living things need, including dioxide., oxygen, and d. is an abiotic factor that is essential for all life processes that take place in cells, such as photosynthesis and respiration. e. Soil is a(n) factor that includes a biotic part called animals; soil that is, which is made up of decayed remains of plants and usually has a high humus content. 3. factors are the living or once-living things in an ecosystem. B. Habitats 1. The place within an ecosystem that provides food, water, shelter, and other biotic and abiotic factors an organism needs to survive and reproduce is the organism s. 2. Animals have a variety of depending on time of day, season, or availability of specific resources. 3. Plants have habitats that depend on factors, such as amount of water or sunlight that is usually available. 10 Interactions of Life
Lesson Outline continued 4. can disappear if there is a significant change in biotic or abiotic in an ecosystem; wildfires,, and flooding are examples of changes that can habitats. C. Populations 1. The group that includes all the organisms of the same species that live in the same area at the same time is known as a(n) all the grass in a vacant lot forms a plant. ; for example, 2. A(n) is made up of all the populations living in the same area at the same time; for example, dandelions, and grasses are part of a vacant-lot community. 3. Overcrowding affects the size of a population because it leads to and. of pigeons, a. The size of a population compared to the amount of space available is called the where the population lives. ; it is calculated by dividing the number of in the population by unit area or volume of space b. If a place has a(n) population density, organisms often live so close together that they aren t able to get all the they need to survive; this also allows to spread more easily, decreasing organisms survival. 4. Populations increase when the number of is larger than the number of. 5. Changes in the biotic and abiotic factors in an ecosystem can force organisms to die out or to. Interactions of Life 11
Content Practice A LESSON 1 Directions: Complete the crossword puzzle with the correct terms from the word bank. abiotic factor biotic factor community ecosystem habitat population density 3 2 1 4 5 Across 3. all the living and nonliving things in the environment in a given area 4. the area within an ecosystem that provides food, water, shelter, and other biotic and abiotic factors an organism needs to survive and reproduce 6. a nonliving part of an ecosystem 6 Down 1. all the populations living in an ecosystem at the same time 2. the size of a population compared to the amount of space available 5. a living or once-living thing in an ecosystem Interactions of Life 13
Content Practice B LESSON 1 Directions: Answer each question in the space provided. Question Answer 1. How does a population differ from a community? 2. What is population density? 3. What formula is used to calculate population density? 4. An area measuring 5 m 2 contains 50 earthworms. What is the population density of the earthworms? 5. How does high population density affect resource availability? 6. How does high population density affect the health of organisms? 14 Interactions of Life
Quick Vocabulary Lesson 1 Lesson 2 abiotic factor nonliving part of an ecosystem atmosphere the whole mass of air surrounding Earth biotic factor living or once-living things in an ecosystem community all the populations living in the same area at the same time ecosystem all the living things and nonliving things in a given area habitat place within an ecosystem that provides food, water, shelter, and other biotic and abiotic factors an organism needs to survive and reproduce population all the organisms of the same species that live in the same area at the same time population density size of a population compared to the amount of space available commensalism symbiotic relationship in which one organism benefits but the other neither benefits nor is harmed competition demand for resources, such as food, water, and shelter, in short supply in a community mutualism symbiotic relationship in which both organisms benefit niche way a species interacts with abiotic and biotic factors to obtain food, find shelter, and fulfill other needs overpopulation when a population becomes so large that it causes damage to the environment parasitism symbiotic relationship in which one organism benefits while the other is harmed predation act of one organism, a predator, feeding on another organism, its prey symbiosis close, long-term relationship between two species that usually involves an exchange of food or energy Interactions of Life 3