Name___________________________________________________________Date____________________________Period______ Ecology Test Review Key What is Ecology? (pg. 63) Ecology is the study of interactions between organisms and their environments, focusing on energy transfer. It is a science of relationships. All living factors are called biotic factors. (pg. 90) Ex. Plants, animals, etc. All nonliving factors are called abiotic factors. (pg. 90 ) Ex. Climate, soil, rocks, water, etc. Levels of Organization in the Biosphere (pgs. 21, 63-64, 90-91) Species → Population → Community → Ecosystem → Biome → Biosphere 1. Species - Group of organisms so similar to one another that they can breed and produce fertile offspring. 2. Population - Groups of individuals that belong to the same species and live in the same area. 3. Communities - Assemblages of different populations that live together in a defined area. 4. Ecosystems – Collection of all the organisms that live in a particular place, together with their nonliving, or physical, environment. Habitat- (pg. 90) the place in which an organism lives out its life (address) 5. Biome -- Group of ecosystems that have the same climate and similar dominant communities. 6. Biosphere -- Contains the combined portions of the planet in which all of life exists, including land, water, and air, or atmosphere. PRACTICE: Use the terms above in the levels of organization section from above to fill in the following: What term is used to refer to each of the following? Habitat 1. Lake Houston (location) Species Ecosystem Population 2. Mississippi river and all of the forms of life that are sustained by it 3. A flock of ducks Population Biome 4. The Sahara desert Biosphere 5. All livable areas on Earth Community 6. The deer, ducks, shore birds, fish and rabbits living in and around Lake Houston Community Ecosystem ENERGY FLOW THROUGH AN ECOSYSTEM The flow of energy through an ecosystem begins with thesun, and is passed on through various organisms: sun producers consumers decomposers Producers – autrophic organisms that are able to make their own food from inorganic substances. Examples: (pg. 67) plants, algae, bacteria Consumers – heterotrophic organisms that get energy by eating producers or other consumers. Examples: (pg. 68) animals, decomposers Types of Consumers: (pg. 69) 1. Herbivores– eatsonly plants Ex. Deer, cow, rabbit, insects 2. Carnivores– Eatsonly meat Ex. hawk, lion, sharks, 3. OmnivoresEatsboth plants and animals Ex.humans Level of Consumers: Use the three types of consumers from above to fill in the following blanks: Primary consumer Secondary consumer Tertiary consumer 4th ….. herbivores carnivores (omnivores can be a 1st, 2nd or higher level consumer) Decomposers – obtain energy from dead and decaying organisms. (pg. 69) Examples: bacteria, fungus, sow bugs, earthworms FEEDING RELATIONSHIPS (pg. 69-70) Each step in a food chain or web is called a trophic level, or a feeding relationship between organisms. FOOD CHAIN one way flow of energy Illustrates only one feeding relationship FOOD WEB many possible feeding relationships within an ecosystem. (Label each trophic level below) 5th 2nd Tertiary consumers 4th Arrows show the flow of energy and matter. Quaternary consumers 3rd 2nd 1st Secondary consumers Primary consumers Producers ECOLOGICAL PYRAMIDS (pg. 72-73) Ecological pyramids diagram that shows the relative 1. What would happen to this food web is the plants were removed?All organisms would die…no energy 2. Which organism is most vulnerable to changes in populations? Plants 3. What happens to the owl population if the foxes we killed off by humans? increase because there is more food for them. amounts of energy or matter contained within each trophic level in a food chain or food web.in a food chain or web. Pyramid of Energy A pyramid of energy is used to illustrate the amount of usable energy at each trophic level. • Only 10% is passed on to the next trophic level • The other 90% is lost/given off as heat. Pyramid of Numbers As you go further down a food chain, the numbers of organisms decrease because there is less energy available! *Compare the pyramid of energy to the pyramid of numbers. Why must there be so many more individuals at lower trophic levels? Because there is less energy available. 3rd consumers Secondary consumers Ecological Pyramids: (pg. 72-73) 1. 2. 3. 4. 5. 6. Level 3 Level 2 Level 1 Symbiotic Relationships Which trophic level contains autotrophic organisms? Level 1 Which trophic level contains herbivores? Level 2 Which trophic level contains carnivores? Level 3 Which trophic level contains the most available energy? Level 1 Which trophic level contains the least available energy? Level 3 How much energy is transferred to the next trophic level? 10% 3 Types of Symbiosis: 1. Parasitism: one organism (parasite) benefits and the other is harmed (host). EX: ticks feed on the blood of other animals. 2. Commensalism: One organism benefits and the other organism is neitherharmed or helped.EX: barnacles on a whale or birds building nests in trees. 3. Mutualism Both organisms benefit from the relationship. EX: pollination of flowers Predator-Prey Relationships Predation: interaction in which one organism captures and feeds on another organism. Predator: organism that does the killing and eating. Prey: Organism that iseaten (food). NUTRIENT CYCLES: WHAT HAPPENS TO THE NUTRIENTS WHEN ORGANISMS DIE? Energy cannot be recycled or used again. However, nutrients/elements in an ecosystem can be recycled. The Carbon Cycle Pg. 77 Decomposers Directions: Use the diagrams above, and the diagrams and text to answer the following: 1. (pg. 77) Name and discuss the process that removes carbon dioxide from the atmosphere? Plants and other producers remove carbon (CO2)from the air through Photosynthesis. 2. Name and discuss the processes in which carbon dioxide is returned to the atmosphere?Carbon (CO2)is put back into the air through the burning of fossil fuels (combustion), by plants and animals through cellular respiration and by decomposers through cellular respiration. The Nitrogen Cycle Pg. 78 by bacteria and/or lightning Nitrogen Facts Air is 78% nitrogen Nitrogen is one of the elements found in plant fertilizers Protein contains nitrogen Directions: Use the diagrams above, diagram on pg. 78, and text to answer the following: 1. (pg. 78) Bacteria living in the roots of the plant help the plant by taking Nitrogen from the atmosphere and “fixing” it so the plant can use it. These bacteria live in nodules called legumes. 2. Bacteria living in the soil help plants by taking Nitrogen from the atmosphere and “fixing” it so the plant can use it as fertilizer. 3. What process transforms nitrogen into usable forms that plants can use? Nitrogen fixation 4. Where do animals ultimately get their proteins from? From the plants or from the animals that eat the plants. 5. (pg. 78, fig. 3-14) How has farming affected the nitrogen cycle?Farmers can use chemical fertilizers adding Nitrogen to the soil, or they can rotate crops, planting legumes to add nitrogen to the soil.
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