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Unit I Ch1 Life Sc Method - Teresa Audesirk • Gerald...

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Unformatted text preview: Teresa Audesirk • Gerald Audesirk • Bruce E. Byers Biology: Life on Earth Chapter 1 An Introduction to Life on Earth What is Science? What is Natural Causality Study of Natural phenomena Natural events occur as a result of natural cause The Scientific Method: procedure for studying science or Problem Preliminary Information Data/Discussion The Scientific Method Hypothesis Hypothesis Experiment Control possible explanation / educated guess tests hypothesis in controlled environ. standard of comparison vs. 1 Experimental Variable correlate this w/observation Must communicate in detail Experiments of Francesco Redi OBSERVATION: Flies swarm around meat left in the open; maggots appear on meat. QUESTION: Where do maggots on meat come from? HYPOTHESIS: Flies produce maggots PREDICTION: IF keep flies away from meat, THEN will prevent the appearance of maggots. EXPERIMENT: C O N T R O L E X P T. Obtain identical pieces of meat and two identical jars Place meat in each jar. Leave jar uncovered Experimental Variable: gauze prevents entry of flies Cover jar with gauze Leave exposed for several days Controlled Variables: clean jars, Leave covered for several days similar pieces of meat, time, temperature, place Flies swarm around and maggots Flies kept from meat; no maggots Results appear appear CONCLUSION: Spontaneous generation of maggots from meat does not occur; flies are probably the source of maggots. Scientific Theories Scientific Theory Scientific Theory Explanation of natural phenomena More general & reliable than Hypothesis Survived through challenges Examples Atomic, Gravitation, Cell, Evolution Never permanent or final “truth” Characteristics of Living Things Characteristics of Living Things 1: Complex, organized and made of cells 2: Respond to stimuli 3: Homeostasis maintains internal conditions 4: Must get nutrients & energy 5: Growth 6: Reproduce themselves 7: Capacity to evolve Salt; Organized but simple Organized Oceans; Complex but unorganized Complex Water flea; Organized and complex Organized and complex Complex, Organize d & made of Cells Respond to Stimuli Internal Internal Stimuli External Stimuli Body temp, H2O levels, Blood sugar levels, hunger Sound, Temp, Pain Taste: avoid bitterness Plants grow toward light Homeostasis Body “staying the same” Body “staying the same” Examples sweat when hot shiver when cold thirst when H2O is low physical repair Maintain pH, salt, sugar, etc. levels So proteins fold normally Preventing disintegration requires energy Acquire Nutrients and Energy Food Food Nutrients extract nutrients and energy (ATP) by metabolism sum total of all chemical reactions needed for life atoms & molecules Energy ability to do work Heterotroph Consumer; eats other organisms Who? Animals, Fungi, most Bacteria Metabolism Autotroph Producer; Photosynthesis 6H2O + 6CO2 C6H12O6 + 6O2 Who? Plants, Algae, some Bacteria ll energy flows from sun ll energy flows from sun Usable energy decreases by decomposers Reproduction Perpetuation of parents’ genetics Stored in Chromosomes = DNA + protein Genes = segments of DNA that code for RNA Growth Growth Homeostasis + Increase in size/mass Genetically programmed Timing, Size, Shape Evolution Descent of modern organisms with modifications from preexisting Descent of modern organisms with modifications from preexisting life forms Result of 3 Natural Processes enetic Variation Inheritance atural Selection Populations extremely variable Much variability is inherited via genes Survival is competitive Good” genes (help grow & reproduce) passed on more often = Adaptation (structure, physiology, behavior) Bad” genes passed on less often More time more change Eventually much different Evolution Stable Environment Stable Environment Oceans – Shark = “Living Fossil” Changing Environment Species must adapt or go extinct Eg. Dinosaurs, Mayans Evolution: Unifying Theory of Biology Explains origin & diversity of life Extremophiles Extremophiles The domain Bacteria The kingdom Plantae (domain Eukarya) The domain Archaea (Extremophiles) The kingdom Fungi (domain Eukarya) A protist (domain Eukarya) The kingdom Animalia (domain Eukarya) ...
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