3. Chapter: Interactions of Living Things Table of Contents Section 3: Matter and EnergyMatter and Energy Section 1: The Environment Section 2: Interactions Among Living OrganismsInteractions Among Living Organisms

4. Ecology is the study of the interactions among organisms and their environment. Ecologists are scientists who study these relationships. Ecology The Environment 1 1

5. Ecologists organize the environmental factors that influence organisms into two groups—nonliving and living or once-living. Abiotic (ay bi AH tihk) factors are the non- living parts of the environment. Ecology The Environment 1 1 Living or once-living organisms in the environment are called biotic (bi AH tihk) factors.

6. In any environment, birds, insects, and other living things, including humans, depend on one another for food and shelter. They also depend on the abiotic factors that surround them, such as water, sunlight, temperature, air, and soil. Abiotic Factors The Environment 1 1

7. All living organisms need water to survive. Water is an important part of the cytoplasm in cells and the fluid that surrounds cells. Water The Environment 1 1 Respiration, photosynthesis, digestion, and other important life processes can only occur in the presence of water.

8. Salt water accounts for 97 percent of the water on Earth. It is found in the seas and oceans. Water The Environment 1 1

9. The availability of sunlight is a major factor in determining where green plants and other photosynthetic organisms live. Light and Temperature The Environment 1 1 By the process of photosynthesis, energy from the Sun is changed into chemical energy that is used for life process.

10. Some areas of the world have a fairly consistent temperature year round, but other areas have seasons during which temperatures vary. Light and Temperature The Environment 1 1 Water environments throughout the world also have widely varied temperatures.

11. Air is composed of a mixture of gases including nitrogen, oxygen, and carbon dioxide. Air The Environment 1 1 Polluted air can cause the species in an area to change, move, or die off. Most plants and animals depend on the gases in air for respiration.

12. Clouds and weather occur in the bottom 8 km to 16 km of the atmosphere. Air The Environment 1 1 All species are affected by the weather in the area where they live. Higher altitudes have less air pressure. Few organisms live at extreme air pressures.

13. Soil type is determined by the amount of sand, silt, and clay it contains. Soil The Environment 1 1 Click image to view movie.

14. Different plants need different kinds of soil. Soil The Environment 1 1 Because the types of plants in an area help determine which other organisms can survive in that area, soil affects every organism in an environment.

15. Organisms depend on other organisms for food, shelter, protection, and reproduction. Biotic Factors The Environment 1 1 How organisms interact with one another and with abiotic factors can be described in an organized way.

16. The living world is highly organized. Atoms are arranged into molecules, which in turn might be organized into cells. Levels of Organization The Environment 1 1 Cells form tissues, tissues form organs, and organs form organ systems. Together, organ systems form organisms. Click image to view movie.

17. The living world is organized in levels. Levels of Organization The Environment 1 1 An organism is one individual from a population.

18. All of the individuals of one species that live in the same area at the same time make up a population. Levels of Organization The Environment 1 1

19. The populations of different species that interact in some way are called a community. Levels of Organization The Environment 1 1

20. All of the communities in an area and the abiotic factors they interact with make up an ecosystem. Levels of Organization The Environment 1 1

21. A biome is a large region with plants and animals well adapted to the soil and climate of the region. Levels of Organization The Environment 1 1

22. The level of biological organization that is made up of all the ecosystems on Earth is the biosphere. Levels of Organization The Environment 1 1

23. The biosphere (BI uh sfihr) includes the top part of Earth’s crust, all the waters that cover Earth’s surface, the surrounding atmosphere, and all biomes. Levels of Organization The Environment 1 1

24. 1 1 Section Check Question 1 Water, sunlight, temperature, air, and soil are _______ factors? A. abiotic B. biotic C. biome D. biosphere

25. 1 1 Section Check Answer The answer is A. Abiotic factors are the non- living parts of the environment. Abiotic factors are important in determining which organisms are able to live in a particular environment.

26. 1 1 Section Check Question 2 The _______ is the part of Earth and its surrounding atmosphere that supports life.

27. 1 1 Section Check Answer The answer is biosphere. The biosphere includes the top part of Earth’s crust, all the waters that cover Earth’s surface, the surrounding atmosphere, and all biomes.

28. 1 1 Section Check Question 3 97 percent of Earth’s total water supply is _______ and only 3 percent is _______. NC: 3.02

29. 1 1 Section Check Answer 97% of Earth’s total water is salt water and 3% is fresh water. Water is essential for the survival of all living organisms. NC: 3.02

30. Characteristics of Population— Population Size The number of individuals in the population is the population’s size. If a population is small and made up of organisms that do not move, the size can be determined by counting the individuals. Usually individuals are too widespread or move around too much to be counted. The population size then is estimated. Interactions Among Living Organisms 2 2

31. Characteristics of Population— Population Size The size of human population is increasing each year. Interactions Among Living Organisms 2 2 The size of a population is always changing. The rate of change in population size varies from population to population.

32. Population Density The number of individuals in a population that occupy a definite area is called population density. When more individuals live in a given amount of space the population is more dense. Interactions Among Living Organisms 2 2

33. Population Spacing Another characteristic of populations is spacing, or how the organisms are arranged in a given area. They can be evenly spaced, randomly spaced, or clumped together. Interactions Among Living Organisms 2 2

34. Limiting Factors All ecosystems have a limited amount of food, water, living space, mates, nesting sites, and other resources. A limiting factor is any biotic or abiotic factor that limits the number of individuals in a population. Interactions Among Living Organisms 2 2

35. Limiting Factors Competition is the struggle among organisms to obtain the same resources needed to survive and reproduce. As population density increases, so does competition among individuals for the resources in their environment. Interactions Among Living Organisms 2 2

36. Carrying Capacity Carrying capacity is the largest number of individuals of a species that an environment can support and maintain for a long period of time. If a population gets bigger than the carrying capacity of the environment, some individuals are left without adequate resources. Interactions Among Living Organisms 2 2

37. Biotic Potential The maximum rate at which a population increases when plenty of food and water are available, the weather is ideal, and no diseases or enemies exist, is its biotic potential. Most populations never reach their biotic potential, or they do so for only a short period of time. Interactions Among Living Organisms 2 2 Eventually, the carrying capacity of the environment is reached and the population stops increasing.

38. Symbiosis and Other Interactions Symbiosis (sihm bee OH sus) is any close interaction between two or more different species. Mutualism is a symbiotic relationship in which two different species of organisms cooperate and both benefit. Interactions Among Living Organisms 2 2

39. Symbiosis and Other Interactions Commensalism is a form of symbiosis that benefits one organism without affecting the other organism. Parasitism is a symbiotic relationship between two species in which one species benefits and the other species is harmed. Interactions Among Living Organisms 2 2

40. Predation Predation is the act of one organism hunting, killing, and feeding on another organism. Owls are predators of mice. Interactions Among Living Organisms 2 2 Mice are their prey.

41. Predation Predators are biotic factors that limit the size of the prey population. Availability of prey is a biotic factor that can limit the size of the predator population. Interactions Among Living Organisms 2 2

42. Habitats and Niches The role, or job, of an organism in the ecosystem is called its niche (NICH). What a species eats, how it gets its food, and how it interacts with other organisms are all parts of its niche. Interactions Among Living Organisms 2 2 The place where an organism lives is called its habitat.

43. 2 2 Section Check Question 1 Three characteristics of populations are _______, _______ and _______.

44. 2 2 Section Check Answer Three characteristics of populations are size, density and spacing. Population size is the number of individuals in a population. Population density is the number of individuals in a population occupying a defined area. Population spacing describes how organisms are arranged in a given area.

45. 2 2 Section Check Question 2 The role, or job, of an organism in an ecosystem is called its _______. A. carrying capacity B. career C. habitat D. niche

46. 2 2 Section Check Answer The answer is D. The manner in which a species interacts with other organisms, how it obtains food, and what it eats are all aspects of its niche.

47. 2 2 Section Check Question 3 This graph is illustrating human population _______. A. density B. habitats C. size D. spacing

48. 2 2 Section Check Answer The answer is C. Population size is the number of individuals in a population. The size of a population is always changing.

49. Energy Flow Through Ecosystems Food contains nutrients and energy needed for survival. Matter and Energy 3 3 When one organism is food for another organism, some of the energy in the first organism (the food) is transferred to the second organism (the eater).

50. Energy Flow Through Ecosystems Producers are organisms that take in and use energy from the Sun or some other source to produce food. Consumers are organisms that take in energy when they feed on producers or other consumers. Matter and Energy 3 3 When organisms die, other organisms called decomposers take in energy as they break down the remains of organisms.

51. Food Chains A food chain is a model, a simple way of showing how energy, in the form of food, passes from one organism to another. When drawing a food chain, arrows between organisms indicate the direction of energy transfer. Matter and Energy 3 3

52. Food Chains Food chains usually have only three or four links. This is because the available energy decreases from one link to the next link. In a food chain, the amount of energy left for the last link is only a small portion of the energy in the first link. Matter and Energy 3 3

53. Food Webs A food web is a series of overlapping food chains that exist in an ecosystem. A food web provides a more complete model of the way energy moves through an ecosystem. Matter and Energy 3 3

54. Food Webs Matter and Energy 3 3

55. Ecological Pyramids Most of the energy in the biosphere comes from the Sun. Producers take in and transform only a small part of the energy that reaches Earth’s surface. Matter and Energy 3 3

56. Ecological Pyramids An ecological pyramid models the number of organisms at each level of a food chain. The bottom of an ecological pyramid represents the producers of an ecosystem. Matter and Energy 3 3 The rest of the levels represent successive consumers.

57. Energy Pyramid An energy pyramid compares the energy available at each level of the food chain in an ecosystem. A pyramid of energy usually has three or four levels. Matter and Energy 3 3 Only about ten percent of the energy at each level of the pyramid is available to the next level.

58. The Cycles of Matter The law of conservation of mass states that matter on Earth is never lost or gained. It is used over and over again. The carbon atoms in your body might have been on Earth since the planet formed billions of years ago. They have been recycled billions of times. Matter and Energy 3 3

59. Water Cycle The water cycle involves the process of evaporation, condensation, and precipitation. Heat from the Sun causes water on Earth’s surface to evaporate, or change from a liquid to a gas, and rise into the atmosphere as water vapor. Matter and Energy 3 3

60. Water Cycle Eventually, the water vapor changes back into tiny droplets of water. It condenses, or changes from a gas to a liquid. Matter and Energy 3 3 When the droplets become large and heavy enough, they fall back to Earth as rain or other precipitation.

61. Other Cycles in Nature Matter and Energy 3 3 The movement of carbon through Earth’s biosphere is called the carbon cycle.

62. Other Cycles in Nature The nitrogen cycle begins with the transfer of nitrogen from the atmosphere to producers then to consumers. Matter and Energy 3 3 The nitrogen then moves back to the atmosphere or directly into producers again. Phosphorus, sulfur, and other elements needed by living organisms also are used and returned to the environment.

63. 3 3 Section Check Question 1 Most of the energy in the biosphere comes from _______. A. Earth B. lava C. the Sun D. water

64. 3 3 Section Check Answer The correct answer is C. The Sun directly or indirectly provides the energy for all organisms.

65. 3 3 Section Check Question 2 Which describes grass? A. carnivore B. consumer C. decomposer D. producer

66. 3 3 Section Check Answer The answer is D. Grass takes in energy from the Sun for photosynthesis which produces carbohydrates that provide energy for the consumers that feed on the grass.

67. 3 3 Section Check Question 3 Which correctly correlates with the numbered illustration of the water cycle? NC: 3.02

68. 3 3 Section Check A. Precipitation, Evaporation and Condensation B. Condensation, Evaporation and Precipitation NC: 3.02

69. 3 3 Section Check C. Evaporation, Condensation and Precipitation D. Evaporation, Precipitation and Condensation NC: 3.02

70. 3 3 Section Check Answer The answer is C. During the water cycle, water from Earth’s surface evaporates into the atmosphere, condenses to form clouds then falls back to Earth in the form of precipitation. NC: 3.02

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