Unit 2 Ecology Study Guide. Niche Autotrophs Heterotrophs Decomposers Demography Dispersion

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1 Vocabulary to know: Ecology Ecosystem Abiotic Factors Biotic Factors Communities Population Unit 2 Ecology Study Guide Niche Autotrophs Heterotrophs Decomposers Demography Dispersion Growth Rate Carrying Capacity Producers Consumers Food Chain Food Web 1. Introduction to Ecology a. Explain why two species are not able to occupy the niche? Because there are a limited number of resources and one will eventually outcompete the other. b. Completive exclusion states that two species competing for the same resources cannot coexist. When is competitive exclusion most likely to occur? Between two similar species within the same trophic level. c. Put the following in order of who eats who: primary consumers, decomposers, tertiary consumer, producer, secondary consumer. Tertiary consumer eats Secondary consumer which eats Primary consumer which eats Producer, decomposers break down all levels to return the energy and nutrients to the ecosystem. d. Put the following in order of the largest to fewest in number in an ecosystem: primary consumers, tertiary consumer, producer, secondary consumer. Largest Smallest Population: Producer Primary Consumer Secondary Consumer Tertiary Consumer e. What is a trophic level? Any class of organisms that occupy the same position in a food chain, such as primary consumers, secondary consumers, and tertiary consumer. f. Only 10% of energy stored at each trophic level in an ecosystem can be passed into the next trophic level. What happens to the remaining energy? It is lost as heat. g. What would organisms in the same trophic level compete for? Food resources. h. Which group (consumer, producer) has the most total energy and why? Producers, because they get their energy directly from the sun and then energy is lost at each subsequent level. i. What is biological magnification AND what organism is most affected? They process whereby certain substances such as pesticides or heavy metals move up the food chain and exist in greater concentrations within organisms at the top of the food chain (tertiary consumers).

2 2. Ocean Floor Vent Communities a. How are chemosynthesis and photosynthesis similar? How are they different? Producers capture energy from the sun to get energy while consumers must gain their energy from eating other organisms. b. Which is more common in plants: chemosynthesis or photosynthesis? Photosynthesis. c. Which organisms use chemosynthesis to produce energy without sunlight? Some bacteria (prokaryotes) 3. Carbon Cycle a. What is released into the atmosphere by burning fossil fuels? Carbon Dioxide b. How does carbon leave the atmosphere? Plants convert the Carbon Dioxide in the atmosphere to the organic molecule glucose. c. How do organisms at the top of the food chain get carbon? Organisms at the top of the food chain have to get carbon through consumption of other organisms. 4. Nitrogen Cycle a. Why do living organisms need Nitrogen? Nitrogen in essential for making proteins. b. What type of organisms are nitrogen fixers? And what do they do? Bacteria! They take nitrogen from the atmosphere is converted into ammonia in the soil, where it may be more readily used by plants. Basic Chemistry c. How do legumes fit into the nitrogen cycle? Legumes have a symbiotic relationship with nitrogen fixing bacteria. d. Most fixed nitrogen coming from bacteria living a symbiotic relationship with which organisms? Legumes! e. What is eutrophication and how does it affect species? Nutrient enrichment in lakes caused by fertilizers that contain nitrogen and phosphorus. The added nutrients can cause a dense growth of plant life, which leads to the death of other animals. 1. Draw an atom and label the protons, neutrons, and electrons, including their charges.

3 2. Which electrons are used in bonding? Valence electrons 3. How does a covalent bond form? The sharing of electrons between two atoms. 4. How many electrons are involved in a single, double, and triple covalent bonds? Single-2 Double-4 Triple-6 5. How does an ionic bond form? Transferring electrons from one atom to another. The two atoms are attracted by their opposite charges. 6. How do hydrogen bonds form? Between the opposite charges of two polar covalent molecules. 7. Compare covalent bonds, ionic bonds, and hydrogen bonds. (Suggestion: Use a 3 circle Venn Diagram)

4 Water 9. Explain why water is polar (charges, which atom is positive, which is negative) Oxygen atoms pull/hold electrons more tightly, making it partially negative and hydrogen atoms partially positive. 10. Water has both hydrogen and polar covalent bonds- where is each located? Hydrogen bonds are located between water MOLECULES, while covalent bonds actually bond the hydrogen and oxygen ATOMS together within a water molecule. 11. Explain the following properties of water and how they are important to life a. Cohesion: water molecules attract each other-enables water molecules to hold onto each other and move upwards in plants. b. Adhesion: water molecules attract other polar molecules-causes water droplets to form and allows water molecules to travel up a plant by clinging to the molecules within. c. High Surface Tension: The surface of the water is difficult to break due to the many hydrogen bonds between water-allows insects to walk on the surface. d. Stabilizes Temperatures (high specific heat): water is able to store large amounts of heat without changing temperature; holds a relatively stable temperature-moderates climate and helps organisms resist temperature change. e. Expands When Frozen: The distance between water molecules increases when frozen, allowing ice to float and life to exist under the ice. f. Versatile Solvent: water will form a solution with many materials-allows water to transport nutrients and other important molecules in and out of cells, to the tops of trees, etc. 5. Relationships (from reading) a. Fill in the following chart: Definition Commensalism Mutualism A close relationship between species where one is benefited and the other is neither helped nor harmed. A close relationship between species where both are benefited. Benefits one species? X Benefits the other? Example Some fish and sharks X X Bees and flowers Predation One species eats the other! X Coyotes and rabbits Parasitism A close relationship between species where one is benefited and the other harmed. X Ticks and dogs

5 b. What is mimicry and give an example. The close resemblance of an animal or plant (or part of one) to another animal, plant, or inanimate object. Example: Monarch and Queen butterfly. 6. Keystone Species a. What happens to an ecosystem when a keystone species is removed? The whole ecosystem may collapse. 7. Invasive Species a. How do invasive species impact an environment? Invasive species compete for the same resources as native species and will eventually take over the environment causing a decrease in the diversity of species. b. Why do populations of invasive species grow so quickly? Invasive species do not have any natural predators and the new environment provides a lot of resources so they will grow quickly. 8. Population Growth a. What is carrying capacity? Draw a graph with carrying capacity. The population size the environment can sustain b. Draw a graph showing exponential growth. c. What are the factors that limit the size of a population? Food, water, space and other resources, disease, etc.