Big Idea 17 Interdependence SC.7.L.17.1 Explain and illustrate the roles of and relationships among producers, consumers, and decomposers in the process of energy transfer in a food web. SC.7.L.17.2 Compare and contrast the relationship among organisms such as mutualism, predation, parasitism, competition, and commensalism. SC.7.L.17.3 Describe and investigate various limiting factors in the local ecosystem and their impact on native populations, including food, shelter, water, space, disease, parasitism, predation, and nesting sites. E? What is Ecology? Ecology is the scientific study of interactions among organisms and between organisms and their physical environment. Biosphere: consists of all life on Earth and all parts of the Earth in which life exists, including land, water, and the atmosphere. E? What are biotic and abiotic factors? The biological influences on organisms are called biotic factors. The physical components of an ecosystem are called abiotic factors. Biotic Factors: any living part of the environment with which an organism might interact, including animals, plants, mushrooms, and bacteria. Abiotic Factors: any nonliving part of the environment, such as sunlight, heat, precipitation, humidity, wind or water currents, soil type, and so on. FCAT 2.0 Benchmark Review Big Idea 17 - Interdependence Page 1
E? What methods are used in ecological studies? Regardless of their tools, modern ecologists use three methods in their work: observation, experimentation, and modeling. Each of these approaches relies on scientific methodology to guide inquiry. E? What are primary producers? Primary producers (A.K.A. autotrophs) are the first producers of energy-rich compounds that are later used by other organism. Primary producers are, therefore, essential to the flow of energy through the biosphere. Autotrophs: organism that is able to capture energy from sunlight or chemicals and use it to produce its own food from inorganic compounds; also called a primary producer because they store energy in forms that make it available to other organisms. Most primary producers harness solar energy through the process of photosynthesis. Photosynthesis: process used by plants and other autotrophs to capture light energy and use it to power chemical reactions that convert carbon dioxide and water into oxygen and energy-rich carbohydrates such as sugars and starches. E? How do consumers obtain energy and nutrients? Organisms that rely on other organisms for energy and nutrients are called consumers (A.K.A. heterotrophs). Heterotrophs: organisms that obtain food by eating other organism, also called a consumer. Consumers: another name for heterotrophs, they rely on other organism for their energy and food supply. Autotrophs = Primary Producers Heterotrophs =Consumers FCAT 2.0 Benchmark Review Big Idea 17 - Interdependence Page 2
Types of Consumers Carnivore: consumers that kill and eat other animals. Herbivore: consumers that only eat plants (leaves, seeds, roots, fruit, etc.). Omnivore: consumers that eat both plants and animals. Scavenger: consumers that feast on the dead carcasses of animals that have been killed by predators or have dies of other causes. Detritivores*: feed on detritus particles often chewing or grinding them into even finer particles, they also commonly digest decomposers that live on, and in, detritus particles. Decomposer: feed by chemically breaking down organic matter. *Detrius Particles: small pieces of dead and decaying plant and animal remains. E? How is an ecosystem organized? The smallest level of organization in an ecosystem is a single organism, which belongs to a population that includes other members of its species. The population belongs to a community of different species. The community and abiotic factors together form an ecosystem. Species: a group of similar organisms that can mate with each other and produce offspring that can also mate and reproduce Population: all the members of one species living in the same area Community: all the different populations that live together in a particular area Ecosystem: the community of organisms that live in a particular area, along with their nonliving environment FCAT 2.0 Benchmark Review Big Idea 17 - Interdependence Page 3
E? How does energy flow in an ecosystem? Energy flows in an ecosystem in a one-way stream, from primary producers to various consumers. Food Chain: a series of steps in an ecosystem in which organisms transfer energy by eating and being eaten. The arrows on a food chain point in the direction in which energy flows in an ecosystem. Food Web: network of complex interactions formed by the feeding relationships among the various organisms in an ecosystem. FCAT 2.0 Benchmark Review Big Idea 17 - Interdependence Page 4
Energy Pyramid: a diagram that shows the amount of energy that moves from one feeding level to another in a food web. The most energy is available at the producer level of the pyramid. As energy moves up the pyramid, each level has less energy available than the level below. E? How do adaptation help an organism survive? Every organism has a variety of adaptations that are suited to its specific living conditions and help it survive. Natural Selection: the process by which organisms that are best adapted to their environment are most likely to survive and reproduce. Adaptations: an inherited behavior or physical characteristic that helps an organism survive and reproduce in its environment. Niche: how an organism makes its living and interacts with the biotic and abiotic factors in its habitat. E? What are competition and predation? Two major types of interactions among organisms are competition and predation. Competition: the struggle between organisms to survive as they attempt to use the same limited resources in the same place at the same time. Predation: an interaction in which one organism kills another for food or nutrients. Predator: the organism that does the killing in a predation interaction. Prey: an organism that is killed and eaten by another organism in a predation interaction. FCAT 2.0 Benchmark Review Big Idea 17 - Interdependence Page 5
E? What are the three types of symbiosis? The three main types if symbiotic relationships are mutualism, commensalism, and parasitism. Symbiosis: any relationship in which two species live closely together and that benefits at least one of the species. Mutualism: a type of symbiosis in which both species benefit from living together. Commensalism: a type of symbiosis between two species in which one species benefits and the other species is neither helped nor harmed. Parasitism: a type of symbiosis in which one organism live with, on, or in a host and harms it. Parasite: the organism that benefits by living with, on, or in a host in a parasitism interaction. Host: an organism that a parasite lives with, in or on, and provides a source of energy or a suitable environment for the parasite to live. Mutualism Commensalism Parasitism E? How do populations change in size? Populations can change in size when new members join the population or when members leave the population. Immigration: moving into a population. (Think i as in in ) Emigration: leaving a population. (Think e as in exit ) Births and immigration increase a population. Deaths and emigration decrease a population s size. E? What factors limit population growth? Limiting Factor: an environmental factor that causes a population to stop growing or decrease. Some limiting factors are food, shelter, water, space, disease, parasitism, predation, and nesting sites FCAT 2.0 Benchmark Review Big Idea 17 - Interdependence Page 6
FCAT 2.0 Sample Questions: 1. In a pond ecosystem, consumers can range from microscopic shrimp to large carnivorous fish. Limiting factors in the pond ecosystem can include sunlight, carbon dioxide, nutrients, and space. If the amount of sunlight was reduced, what effect would this have on the ecosystem? (SC.7.L.17.2) a. The population of producers would increase b. The biodiversity in the pond would decrease c. The number of primary consumers would increase d. The body size of secondary consumers would decrease 2. Cleaner fish feed on parasites in a shark s mouth and gills. Which of the following best describes the relationship between the cleaner fish and the shark? (SC.7.L.17.2) a. Competitive b. Mutualistic c. Nonexistent d. Parasitic 3. Which one of the following is an example of parasitism? (SC.7.L.17.2) a. Flower and bee b. An orchid growing on a tree c. Clownfish and sea anemone d. Tapeworm and dog 4. Which of the following human activities reduces the level of ozone in the atmosphere? (SC.7.L.17.3) a. Using artificial lighting in scientific polar stations b. Using large banks of solar cells for energy production c. Releasing chlorofluorocarbons from aerosol cans d. Destroying large areas of the equatorial rain forests 5. In a pond, the primary producer is a green alga, Spirogyra; the primary consumer is the crustacean, Daphnia; the secondary consumer is a small fish, the bluegill; and the tertiary consumer is a larger fish, the smallmouth bass. What changes can be expected in the pond if the Daphnia are killed with pesticides? (SC.7.L.17.3) a. The Spirogyra population will probably die b. The bluegill population will increase c. The Daphnia population will eat something else d. The smallmouth bass population will die FCAT 2.0 Benchmark Review Big Idea 17 - Interdependence Page 7
FCAT 2.0 Sample Questions: 6. Use the food web above to answer the following question: Which organism from the above web is sometimes a primary consumer and sometimes a secondary consumer? (SC.7.L.17.1) a. Bird b. Carrots c. Owl d. Mouse FCAT 2.0 Benchmark Review Big Idea 17 - Interdependence Page 8