Content Vocabulary LESSON 2 Directions: Each of the sentences below is false. Make the sentence true by replacing the underlined word with a term from the list below. Write your changes on the lines provided. NOTE: You may need to change a term to its plural form. commensalism competition mutualism niche overpopulation parasitism predation symbiosis 1. Overpopulation occurs when two or more organisms interact to obtain the same biotic or abiotic factor at the same time. 2. Parasitism occurs when one organism kills and eats another organism. 3. When moss grows on tree bark, the moss benefits; the tree does not benefit and is not harmed. This is an example of mutualism. 4. Although two or more species can share the same habitat, they do not share the same symbiosis. 5. Mutualism, commensalism, and parasitism are types of predation. 6. Commensalism is a symbiotic relationship in which one organism benefits while the other is harmed. 7. When mutualism occurs, disease can spread rapidly and the environment can be damaged. 8. A symbiotic relationship in which both organisms benefit is called a(n) niche. Interactions of Life 29
Lesson Outline LESSON 2 A. Niches 1. A(n) is the part of an ecosystem that provides an organism with things it needs to live. 2. Usually many different share a habitat. 3. The way a species interacts with abiotic and biotic factors to obtain food, find shelter, and fulfill other needs is the of that species. 4. Although two species might share a(n), no two species ever share the same. B. Competition 1. The demand for resources such as food, water, and shelter that are in short supply in a community describes. a. Members of the same or different can compete for the same resources such as food, water, or shelter. b. limits the size of a(n), sometimes forcing members to leave an area if they are to survive. 2. When a population becomes so large that it causes damage to the environment, occurs. a. Individual organisms in an environment for limited resources, such as food. b. If organisms facing limitations in their resources cannot move elsewhere, they might be forced to live too close together, causing the environment to become. c. Overpopulation is because organisms eventually move away,, or die of ; then the population C. Competing with Humans return to their normal levels., and the resources in the 1. Humans compete with other organisms for biotic and abiotic factors such as, living, and water. 30 Interactions of Life
Lesson Outline continued 2. One example of human with other species is diverting D. Predation to irrigate crops; another example is cutting down that serve as shelter for migrating monarch butterflies. 1. An organism that hunts and kills other organisms for food is a(n) organism is. ; an organism that is hunted and eaten by another 2. The act of one organism, a predator, feeding on another organism, its prey, is called. 3. A close, long-term relationship between two species that usually involves an exchange of food or energy is called. a. is a symbiotic relationship in which both organisms benefit. b. is a symbiotic relationship in which one organism benefits but the other neither benefits nor is harmed. c. is a symbiotic relationship in which one organism benefits while the other is harmed. Interactions of Life 31
Content Practice A LESSON 2 Directions: On the line before each definition, write the letter of the term that matches it correctly. Each term is used only once. 1. the way a species interacts with abiotic and biotic factors to obtain food, find shelter, and fulfill other needs 2. describes interactions between two or more organisms that need the same abiotic or biotic factor at the same time 3. occurs when a population becomes so large that it causes damage to the environment 4. the act of one organism, a predator, feeding on another organism, its prey A. commensalism B. competition C. mutualism D. niche E. overpopulation F. parasitism G. predation H. symbiosis 5. a close, long-term relationship between two species that usually involves obtaining food or energy 6. a symbiotic relationship in which both organisms benefit 7. a symbiotic relationship in which one organism benefits and the other does not benefit and is not harmed 8. a symbiotic relationship in which one organism benefits while the other is harmed Interactions of Life 33
Key Concept Builder LESSON 2 Key Concept How does a niche differ from a habitat? Directions: On the line before each statement, write the letter of the correct answer. 1. An area within an ecosystem that provides an organism with the resources it needs for life is a(n) A. niche. B. habitat. C. abiotic factor. 2. A habitat is usually A. shared by many species. B. inhabited by only one species. C. shared by no more than two species. 3. The way a species interacts with abiotic and biotic factors to obtain food, find shelter, and fulfill other needs is its A. niche. B. habitat. C. ecosystem. 4. Each species that shares a habitat has a A. shared niche. B. separate niche. C. separate ecosystem. 5. A coral reef is an example of a A. niche. B. habitat. C. parasite. 6. A filefish scraping algae from the coral to eat is an example of a A. niche. B. habitat. C. parasite. 36 Interactions of Life
Key Concept Builder LESSON 2 Key Concept How does a niche differ from a habitat? Directions: Answer each question or respond to each statement on the lines provided. 1. What is a habitat? 2. What is a niche? 3. Are habitats and niches shared among species? Explain. 4. Give an example of a habitat and a niche in your area. Directions: Draw a habitat for an organism of your choice in the space provided. Show the organism s niche. Write a caption that describes your drawing. Interactions of Life 37
Key Concept Builder LESSON 2 Key Concept In what ways can organisms interact in an ecosystem? Directions: Complete the concept map by placing the letter for the correct term, phrase, or statement from the word bank in the space provided. Each term, phrase, or statement is used only once. A. a close, long-term relationship between two species that usually involves obtaining food and energy B. Both organisms benefit. C. commensalism D. competition E. One organism benefits but the other does not benefit and is not harmed. F. parasitism G. predation Types of interactions Organisms need the same abiotic or biotic factor at the same time. symbiosis mutualism A predator feeds on a prey. One organism benefits while the other is harmed. 38 Interactions of Life
Key Concept Builder LESSON 2 Key Concept In what ways can organisms interact in an ecosystem? Directions: Label the type of symbiosis shown in each illustration. Then write a caption explaining the relationship between the organisms shown in each illustration. Type of symbiosis: Caption: Type of symbiosis: Caption: Type of symbiosis: Caption: Interactions of Life 39
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
Lesson Quiz A LESSON 2 True or False Directions: On the line before each statement, write T if the statement is true or F if the statement is false. If the statement is false, change the underlined word to make it true. Write your changes on the lines provided. 1. Species share the same habitat, but not the same niche. 2. When overpopulation occurs, it causes damage to the environment. 3. Symbiosis is a close relationship between two communities. Matching Directions: On the line before each definition, write the letter of the term that matches it correctly. Each term is used only once. 4. a relationship between two organisms in which both organisms benefit 5. an interaction between two or more organisms that need the same resources 6. a relationship between two organisms in which one organism benefits and the other organism is not helped or harmed 7. a relationship between two organisms in which one organism benefits and the other organism is harmed 8. the act of one organism feeding on another organism A. commensalism B. competition C. mutualism D. parasitism E. predation 42 Interactions of Life