Species, Communities and Ecosystems

Species, Communities and Ecosystems Ecological Terms Differentiate, with examples, between abiotic and biotic factors The non-living chemical and physical factors in an environment (which affect ecosystems) Abiotic: …………………………………………………………………………………………………………………………………….......... E.g. Temperature, pH, salinity, humidity, wind, etc. ………………………………………………………………………………………………………………………………………………….......... The living components of an environment which affect an ecosystem Biotic: ……………………………………………………………………………………………………………………………………….......... E.g. Disease (pathogens), competition, predation, mate availability, etc. ………………………………………………………………………………………………………………………………………………….......... With the aid of the following diagram, define the following terms Species Population Community Habitat Ecosystem A group of organisms that can potentially interbreed to produce fertile viable offspring Species: …………………………………………………………………………………………………………………………………….......... ………………………………………………………………………………………………………………………………………………….......... A group of organisms of the same species that are living in the same area at the same time Population: ……………………………………………………………………………………………………………………………….......... ………………………………………………………………………………………………………………………………………………….......... A group of populations living together and interacting with each other within a given area Community: ……………………..……………………………………………………………………………………………………….......... ………………………………………………………………………………………………………………………………………………….......... The environment in which a species normally lives, or the location of a living organism Habitat: …………………………………………………………………………………………………………………………………….......... ………………………………………………………………………………………………………………………………………………….......... A community AND its abiotic environment (i.e. habitat) Ecosystem: ……………………………………………………………………………………………………………………………….......... ………………………………………………………………………………………………………………………………………………….......... Modes of Nutrition Define nutrient A nutrient is a substance (found in food) used by an organism to survive, grow and reproduce ………………………………………………………………………………………………………………………………………………….......... There are 6 major nutrients: carbohydrates, lipids, proteins, vitamins, minerals and water ………………………………………………………………………………………………………………………………………………….......... Distinguish between autotroph and heterotroph Synthesise their own organic molecules from simple inorganic substances (e.g. CO2, nitrates) Autotroph: …………………….………………………………………………………………………………………………………….......... Energy derived from sunlight (photosynthesis) OR oxidation of molecules (chemosynthesis) ………………………………………………………………………………………………………………………………………………….......... Obtains their organic molecules from other organisms Heterotroph: …………………………………………………………………………………………………………………………….......... (Certain organisms may use both forms of nutrition – mixotrophs) ………………………………………………………………………………………………………………………………………………….......... Differentiate between the following types of heterotrophs, providing an example of each Ingest organic molecules from living or recently killed organisms Consumer: …………………….………………………………………………………………………………………………………….......... E.g. Mammals (wolves, bears, humans, etc.) ………………………………………………………………………………………………………………………………………………….......... Ingest organic molecules found in the non-living remnants of organisms Detritivore: ……………………………………………………………………………………………………………………………….......... E.g. Dung beetles (detritus), millipedes (leaf litter / humus) ………………………………………………………………………………………………………………………………………………….......... Release digestive enzymes and then absorb the external products of digestion Decomposer: …………………………………………………………………………………………………………………………….......... E.g. Saprotrophs (bacteria, fungi) ………………………………………………………………………………………………………………………………………………….......... Ecosystem Sustainability Compare the fate of energy and nutrients within an ecosystem Energy flows through an ecosystem and is lost – requires resupply from a constant energy source (e.g. sun) ………………………………………………………………………………………………………………………………………………….......... Nutrients are finite and are recycled within a closed ecosystem ………………………………………………………………………………………………………………………………………………….......... Outline the role of decomposers in maintaining nutrient supply Decomposers release enzymes to externally break down organic material ………………………………………………………………………………………………………………………………………………….......... This allows for inorganic compounds to be replenished within the environment (e.g. returned to the soil) ………………………………………………………………………………………………………………………………………………….......... Define mesocosm A mesocosm is an enclosed environment that allows a small part of the natural environment to be viewed ………………………………………………………………………………………………………………………………………………….......... under controlled conditions ………………………………………………………………………………………………………………………………………………….......... Identify two methods of population sampling Quadrats 1. …………………………………………………………………………………………………………………………………………………... Transects 2. …………………………………………………………………………………………………………………………………………………... Chi-Squared Test Complete the chi-squared test for association based on the following information The distribution of two species of limpets (L. pelta and L. scutum) are recorded via 150 quadrats. 25 = both species 45 = L. pelta only 30 = L. scutum only 50 = neither species 1. Identify Hypotheses There is no significant difference in the distribution of the species (i.e. it is random) Null Hypothesis: ……………………………………………………………………………………………………………………….......... There is a significant difference in species distribution (i.e. they are associated) Alternative Hypothesis: …………………………………………………………………………………………………………….......... 2. Calculate Frequencies Observed Frequencies: L. pelta Expected Frequencies: L. scutum L. scutum Present Absent Total Present Absent Total Present 25 45 70 Absent 30 50 80 Total 55 95 150 L. pelta Present 25.7 44.3 70 Absent 29.3 50.7 80 Total 55 95 150 3. Calculate Chi-Squared Value Both present !−! ! ! L. pelta only 0.019 0.017 L. scutum only Neither present 0.011 0.009 0.019 + 0.017 + 0.011 + 0.009 = 0.056 ! ! : …………………...……………………………………………………………………………………………………………………….......... 4. Determine Statistical Significance Probability of Exceeding Critical Value Degree of Freedom 0.90 0.75 0.50 0.25 0.10 0.05 0.01 1 0.016 0.102 0.455 1.32 2.71 3.84 6.63 2 3 0.211 0.584 0.575 1.212 1.386 2.366 2.77 4.11 4.61 6.25 5.99 7.81 9.21 11.34 There is no significant difference between distributions (species NOT associated) Conclusion: ………………………………………………………………………………………………………………………………..........