Ecology Ch 1 TEST
Ecology Ch 1 TEST Biol 271
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This 4 page Class Notes was uploaded by JoMarie Notetaker on Monday January 11, 2016. The Class Notes belongs to Biol 271 at University of Alaska taught by Johanna Fagen in Fall 2016. Since its upload, it has received 34 views. For similar materials see Ecology in Biology at University of Alaska.
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Date Created: 01/11/16
Chapter 1 - Introduction: The Web of Life Case Study - frogs with deformities discovered by elementary/middle schoolers while obtaining frogs for science project - frogs had missing or extra legs - 30 - 40% of frogs in pond were deformed - discovery of deformity led scientist to the conclusion that the deformities among amphibians was widespread - found in 46 states, Europe, Asia, and Australia - deformities coincided with declining amphibian numbers, possible extinction - decline generally means deteriorating local environment Importance of understanding amphibian decrease: - recent trend seen worldwide - some declines in number were observed in refuges and protected areas, far from human activity - biological indicators of environmental conditions - Amphibians - permeable skin - no hair, scales, or feathers - eggs lack shell or protective covering - exposed to water and air pollution due to life history - change in temp - varying UV Ecology - the science of how organisms affect, and are affected by, other organisms and their environment Concept 1.1 Connections in nature - events in the natural world are interconnected - all organisms are connected to features of their environment species that do not interact directly share certain features in environment - “Early Observations…” - parasite Ribeiroia ondatrae, trematode flatworm implanted beads in developing tadpoles to mimic effects of parasite - “Lab experiment tests the role…” - early experiment with beads did not infect animals subjects with parasites to determine if they caused deformities - animal subjects used were not the wild type that had deformities - animal subjects used were not known to have deformities in nature - New experiment - more thorough analysis of parasite on deformities - found four ponds that had the deformed amphibians, 15% - 45% tadpole w deformity - concern dfrmty caused by pollutants, but none were found in the pond - dfrmty not genetically based, somes eggs were taken from pond and reared in lab - Other factors - ponds with abnormal frogs ponds also had an aquatic snail not found in the other ponds w/o abnormal frogs - snail is intermediate host of parasite - parasitic cysts on all frogs with dfrmty, indirect evidence of parasite that causes dfrmty - Another Test - performed controlled experiment - experimental group - group with the factor that is being tested - control group - lacks factor being tested Chapter 1 - Introduction: The Web of Life - collected eggs from pond w/o parasite, and were placed into containers with varying levels of parasites - Outcome - more parasites = greater mortality - most tadpoles survived in control group Field Experiment & multiple factors - Ribeiroia causes dfrmty in multitude of amphibian species - pesticides & parasite = dfrmty - placed tadpoles in two types of ponds = w/ & w/o pesticide - w/i each pond used two types of mesh = one to allow parasites & one that would not - Outcome - smaller mesh prevented deformities in both pond environments - larger mesh with no pesticides = 4% dfrmty - larger mesh with pesticide = 29% dfrmty - every frog with dfrmty had Ribeiroia - parasite needed for dfrmty to occur, higher rate if pest. present - Analysis of Results - presence of pest. weakened ability to fight off parasite? - led to another experiment - reared tadpoles in lab in two different environments (pest. vs. no pest.) - tadpoles in pest. had a lower white blood count - higher rate of Ribeiroia cyst formation Connections in Nature - increase in dfrmty due to higher use of pesticides - use began in 1930, increased since - artificial ponds - agriculture, washed in fertilizer - fertilizer increase growth rate of algae - intermediate host (snail) eats algae - chain of events where increased use of fertilizer has lead to an increase in dfrmty of amphibians We live in an Ecological World - cause one change, may cause other changes that are unintended - aforementioned problem - damming of rivers in Africa created favorable habitat for parasite hosts (snail) that cause schistosomiasis, which can kill and weaken people - change in environment can be detrimental to human health Concept 1.2 Ecology - the study of interactions between all living things and their environments - the study the figures out the distribution and abundance of organisms - branch of biology, different from environmental study - environmental studies - an interdisciplinary study that incorporates concepts from the natural sciences and the social sciences. Public and Professional ideas… - balance of nature Chapter 1 - Introduction: The Web of Life - stable systems, return to normal state when disturbed - each species contribute to the balance - change is important to a system - random events are not when random when studied - naturally occurring forest fires - events in nature are all connected - a change in one part of the system causes change in another part of the system - seven ecological maxims - one action may have multiple effects as all actions are connected 7 Ecological Maxims 1.) “You can never do just one thing.” a.) species interact with one another and are connected to each other and their environment. 2.) “Everything goes somewhere.” a.) all waste material has to go somewhere 3.) “No population can increase their size forever.” a.) limited resources limit growth 4.) “There is no free lunch.” a.) limited amount of energy for each organism b.) must use a bit of energy to obtain food to make more energy c.) energy must be used for other metabolic processes 5.) “Evolution matters.” a.) all living things evolve over time, nothing is static b.) ongoing process as organisms face new situations as the environment changes, as well 6.) “Time matters.” a.) ecosystems change over time b.) past events affect the present, preset will affect the future 7.) “Life would be impossible w/o species interactions.” a.) species depend on one another for energy, nutrients, and home Ecology is broad in scope - focus in: organisms, populations, communities, or ecosystems - population - group of individuals of a single species that live in an area together and interact with other another - how and why population abundance change over time? - community - an association of interacting populations of different species that live in the same area - vary in number of species, size of area, types of species - ecosystem - community of organisms plus the physical environment in which they live - environmental factors that influence population dynamics - temp, precip, nutri, or pH - biosphere - all the world’s ecosystems - all the world organisms and all the environments they live - highest level of biological organization The scale of an ecological study affects what can be learned from it - draw boundaries and set limits - not possible to study everything at once - scale - appropriate dimension of the study to collect data - use of small scales, not all Key terms - evolution - (1) change in the genetic characteristics of a population over time, or (2) descent with modification, the process by which organisms gradually accumulate differences from their ancestors - adaptation - characteristic of an organism that improves its ability to survive and reproduce within its environment - natural selection - individuals with particular characteristics tend to survive and reproduce at higher rate than other individuals because of those characteristics. - if heritable, offspring will have these characteristics - frequency of characteristic may increase over time - producer - organism that can produce its own food, aka autotrophs or primary producers - consumer - organism that obtains energy from eating another organism Chapter 1 - Introduction: The Web of Life - net primary production (NPP) - amount of energy producers make through photosynthesis minus metabolic energy (heat) - NPP varies amongst ecosystems - changes in NPP has large effect on ecosystem - energy is eventually loss as heat, single direction of energy flow - energy cannot be recycled in the same form - nutrients are always recycled - nutrient cycle - cyclic pattern of nutrients between organism and physical environment - nutrients are essential for life, if cycle did not occur, all of life that we know of will stop Concept 1.3 “Ecologists evaluate competing hypotheses about natural systems with experiments, observations, and models.” - observational studies from the field can lead to experimental studies in the lab - variety of methods must be utilized to answer ecological questions Ecologists use experiments… - investigators changes one aspect of environment and observes the effects of the change on natural processes. - when possible; use of control group and experimental group - scale varies widely - sometimes, it is difficult, even impossible, to conduct an experiment - too large of an area - too long of a timespan to (global warming) - info from too small an area, too short of a timespan, or in the lab may provide insufficient information - global warming - climate is warming - how will range of certain species change? cannot be determined as one cannot replicate global warming on the entire planet to determine - use observational studies, small-scale experiments, and quantitative models - observations have seen animals ranges are moving closer to the poles or higher in altitude - compare and contrast how species interact with current environment with a different environment - small-scale experiments & observational studies are utilized in mathematical models Experiments are designed and analyzed… Steps utilized to ensure that experiment is not under the control of the experimenter: 1) replicate each treatment - when results are replicated, variable was not controlled by experimenter 2) assign treatment at random - limit the effects of unmeasured variable 3) use statistical analyses to determine whether treatment has a significant effect - used to determine if results are significant - different methods of statistical analyses exist What we know about ecology is always changing scientific method 1) observe nature and ask a question about those observations 2) use previous knowledge or intuition to develop possible answers to that questions (hypotheses) 3) Evaluate competing hypotheses by performing experiments, gathering carefully selected observations, or analyzing results of quantitative models 4) use results of experiments, observations, or models to modify one or more of the hypotheses, to pose new questions, or to draw conclusions about the natural world
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