Notes on Introduction to General Biology | BIOL 1001, Study notes of Biology

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Biology:

 Levels of Biological Organization : o Biosphere – area on the planet where you can find living things, space on planet earth o Ecosystem – a system formed by the interaction of a community of organisms and their environment o Community – group of living organisms o Population – a group of individuals of the same species  A living thing can be broken down: o Organism – human o Organ system – nervous system o Organ – brain o Tissue – nerve tissue o Cellular – nerve cell o Organelle – mitochondrion / chloroplasts / nucleus o Molecular – water / gluclose / DNA o Atomic – hydrogen / carbon / nitrogen / oxygen o Subatomic – proton / neutron / electron  Physics looks at atomic and subatomic particles, chemistry sees how they react together and apart, biology observes the single cell and how they contribute to a living thing.  ***** What is the Science of Biology? o Life and study / translates : “The study of life”  What are the Characteristics of Living Things? o 1. Their structure is complex and organized.  Complex and organized  Ex. Salt (nonliving), organized but simple  Ex.2 Oceans (full of living and nonliving), complex but unorganized  Ex.3 Water flea (living thing), organized and complex o 2. They acquire material and energy from their surrounding environment.  Ex. 1 – plants utilize CO2 and sunlight to make sugars  Ex.2 animals eat plants o 3. They work to maintain their internal conditions  Organized systems disintegrate  Preventing disintegration requires energy  HOMEOSTASIS means “staying the same”  Sweating when hot, shivering when cold  Feeling thirsty when water is low  Homeostasis requires energy  Opposes natural trend to disintegration

 Obtained from external source  Homeostasis requires physical repair  Parts break down  New materials required for repair  Food supplies material and energy o 4.Growth  Extension of homeostasis  Homeostasis = “staying the same”  Growth = homeostasis plus extra  Organism grows in size/mass  Must acquire more than needed for homeostasis  Genetically programmed  Timing  Space  Shape o 5. Living organisms respond to stimuli  Changes in internal environment  Temperature  water level  blood sugar level  Changes in external environment  seek food and water  avoid bitterness  plants grow toward light o 6. Reproduction  Reproduce themselves in kind (heredity)  Perpetuation of parents’ genetics  Genetic info stored in DNA molecules  Variation o Offspring similar to both parents o Offspring different from either parent  Simple code with complex error correction system o 7. Evolution  Genetic composition of populations changes (evolves)  Differential survival (natural selection) (survival of the fittest)  “Selects” advantageous adaptations  The more time, the more change  Eventually become much different  Not based on a belief system… based on experimental results and observations  3 natural processes drive evolution: o 1. Genetic variation/competition among variants o 2. Not all survive o 3. Adaptive characteristics inherited  How do scientists categorize the diversity of life?

o Biological species concept = if they can breed and reproduce offspring and they can reproduce the same species as well  3 domains of Living Organisms: o Bacteria o Archaea o Eukarya  Domain Eurkarya: o 4 Kingdoms:  Kingdom Protista – almost entirely single celled (ex: Diatoms found in plankton)  Kingdom Fungi – multi-cellular; obtains its food (eats by giving off enzymes which speed up chemical reactions into the environment around it)  Kingdom Plantae – multi-cellular, obtains food through photosynthesis (make their own food)  Kingdom Animalia – multi-cellular, eat food (ingest) o Eukaryotic Organisms:  Single- or multi-celled  Nucleus and other organelles  Larger (10x), more complex  Protists, Plants, Fungi, and Animals  Domain Prokarya (Archaea): (Ex. E-coli)  Single cells  No nucleus or organelles  Smaller less complex  Eubacteria, Archaea  The Science of Biology o All events can be attributed to natural causes o Natural laws apply at all places and all times o People perceive events in similar ways  The Scientific Method o Observation  Something unexpected happens o Hypothesis Explanation; if/then prediction o Experiment controlled test challenge prediction o Conclusion supports or doesn’t support hypothesis  If it doesn’t modify hypothesis!  Scientific Theories o General statements about how things operate  Derived through reasoning from detailed facts to general principles  Survived thorough challenges  Never permanent or final “truth”  Always provisional  Always subject to change

 Used to propose hypothesis o Alexander Fleming: In 1920 a culture dish became contaminated with a mold during one of his experiments  Observation: bacteria wouldn’t grow near mold  Hypothesis: the mold releases a substance that kills off bacteria growing nearby  Experiment: extracted fluid from mold and it inhibited bacterial growth  The fluid was later isolated and called penicillin (the 1st^ antibiotic)  The Nobel Prize in Physiology or Medicine in 1945—“for the discovery of penicillin and its curative effect in various infections diseases”