Bio 171 Exam 1 notes

Bio 171 Exam 1 notes - Brenda Shih Biology 171 Ecology and...

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Brenda Shih Biology 171 Ecology and Evolution Lectures 1-8 Lecture 1: Process of Science Living Organisms Characteristics of a living entity 1. Composed of one or more cells 2. Predominantly carbon and water based 3. Acquires energy and material from surroundings 4. Contains heritable genetic information 5. Responds to environment stimuli 6. Can reproduce 7. Evolves over many generations Hierarchical levels cell and molecular, multi-cellular, population, community, ecosystem, biosphere Diversity of Life Biological knowledge change over time Science self-correcting, understanding of world improve/time Biologists Ask questions, propose hypotheses, test and evaluate hypotheses using evidence observational studies, experiments, computer sim/math models Pasteur’s experiments Hypothesis of spontaneous generation Hypothesis: possible explanation consistent with available data Evidence either supports or doesn’t support a hypothesis In mid 1860’s, ppl believed non-living could generate living organisms Treatment straight necked flask allows colonization by bacteria Control swan-necked flask prevents colonization of bacteria One variable: exposure of broth to colonizing cells by shape of flask After publish findings, peer review and reproducibility Scientific knowledge Fact: observation repeatedly confirmed Theory: explanation for broad patterns in nature, tested many times Theories are overarching explanations that explain broad patterns in nature, are based on evidence, allow scientists to make valid predictions and have been tested in many ways. Supported, modified or replaced as new evidence appears Law: descriptive generalization for how some aspect of natural world behaves under stated circumstances Hypothesis: possible explanation consistent w/ available data Dog experiment dogs more skillful than great apes in deciphering human signals for location of food Possible hypotheses: 1. Candid generalization social canids good at social cues
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Prediction: wolves should do as well as dogs/task 2. Human exposure dogs more experience w/ humans Prediction: puppies should perform poorly/task 3. Domestication process of domestication selected for social cognitive skills in dogs Prediction: dogs should be better at social cognitive skills compared with wolves and variation in experience with humans should not affect performance on task in dogs Experiments support Domestication hypothesis Saharan Desert Ants, how navigate back to nest? Ants use sun’s position as compass Don’t use landmarks Pedometer hypothesis: ants keep track of stride length and # of steps Experiment: variation in leg length Control: leave legs normal length Prediction: ants with stilts go too far, ants with stumps stop short Null: Stride # no effect on navigation Good Experimental Design Control groups
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Bio 171 Exam 1 notes - Brenda Shih Biology 171 Ecology and...

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