Bio 100 SDSU EXAM NEWEST 2025 EXAM QUESTIONS AND CORRECT DETAILED ANSWERS WITH RATIONALES (VERIFIED ANSWERS) |ALREADY GRADED A+

Bio 100 SDSU EXAM NEWEST 2025 EXAM QUESTIONS AND CORRECT DETAILED ANSWERS WITH RATIONALES (VERIFIED ANSWERS) |ALREADY GRADED A+ Ecology - Answers - The study of the interactions between organisms and their environment. At what levels of organization do ecologists work? - Answers - 1. Individual organisms 2. Populations of organisms (same species) 3. Communities of organisms (different species that interact with one another) 4. Ecosystem (all living organisms that interact in a particular area) 5. Biosphere (all organisms) Population Distribution - Answers - Where populations are found on earth What kind of factors determine distribution? - Answers - 1. Abiotic (physical) factors. Non-living like temperature, geography, water availability. 2. Biotic factors (living) predators, parasites, competition of resource What is population density? - Answers - Indicates size, The number of organisms per unit of area/volume (used when there is a great number of organisms in a population. What do r, b, and d symbolize and how are they related? - Answers - B = Birth Rate D = Death Rate R = Population growth Compare and contrast exponential growth and logistic growth. - Answers - Exponential growth: Population growth that is not hindered by a limiting factor. Growth without limits. Logistic Growth: Population size grows and decreases within the carrying capacity due to a limiting factor. What is K? - Answers - Maximum population size that an environment can support. - Result of density-dependent factos - Birth and death rates change - growth rate changes Define density-dependent factors and density-independent factors. - Answers - Density dependent: Lack of food, lack of space. Pretty much things caused by over-population/competition. Density Independent: Fires, floods, natural disasters, etc. What are the 3 types of survivorship curves? - Answers - 1. Type I - High survivorship until old age, then rapid decrease (humans and elephants) 2. Type II - Survivorship decreases at a steady, regular rate (birds) 3. Type III - High mortality in early life, but those that survive live long lives. (sea turtles) Lynx-Hare Cycle - Answers - Predators lag behind the pray. When the amount of hares increase, the amount of lynx will increase because there is plenty of resources. However, if the lynx kill too many hares, there won't be enough resources and they will decrease. Less predators will then allow hare population to increase again. Population age pyramids (triangular vs rectangular) - Answers - Triangular = birth rates high, but death rates high as well. (Developing countries) Rectangular = Low Birth and death rates (slow growth) (industrial countries). What is demographic transition? - Answers - The changing of birth and death rates as a country goes from pre-industrial to industrial to developed. Birth/Death rates of 1. Pre-industrial 2. Industrialization begins 3. Industrialization completed - Answers - 1. not developed - high birth, high death, low population growth 2. Developing - high birth, low death, high population growth 3. Developed - low birth, low death, low population growth. What is the agricultural revolution? - Answers - 8,000 years ago, allowed us to farm more efficiently and produce more food to eat/avoid famine. Medical Revolution - Answers - 20th century . - Less mortalities - Increase in public health, sewage and trash disposals, and new medicines. How have these revolutions affected the population growth? - Answers - Each of these advancements has allowed humans to surpass the carrying capacity and enabled us to live longer and reproduce more often. What sorts of advances have allowed us to "sidestep" our carrying capacity? - Answers - - Expanding into new habitats. - Increasing agricultural productivity - Finding ways to live at higher densities (skyscrapers) - Technology Define Ecological Footprint - Answers - Resources consumed by an individual in comparison to the resources available. Death rate solution - Answers - Wait until resources get scarce and watch more people die one by one. Birth Rate solution - Answers - Limit births, increase education for women Ecosystem - Answers - All organism (the community) and the physical environment at a location Biotic Environment - Answers - - The living organisms within an area - Often referred to as a community Physical (Abiotic) Environment - Answers - - Chemical resources and physical conditions within an area - Often referred to as an organisms habitat Biome - Answers - A regional ecosystem that... - covers a large geographic area - Distribution and characteristics are largely determined by climate. What is primary productivity? - Answers - Autotrophs (make own food) that control the amount of organic material (biomass) produced by photosynthesis per unit time; rate at which energy is converted by photosynthesis - Autotrophs = producers (plants)