Lecture Notes 1 Bio

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Lecture Notes 9/1/07

I. Scientific Study of Life
       A. Levels of Organization in Living Organisms
               1. Biosphere: life-supporting areas of the earth’s surface, deep seas, and a few
               kilometers up into the earth’s atmosphere. The “global ecosystem”.
               2. Ecosystem – composed of
                       a. all living organisms in an area, and
                       b. all the non-living components of the environment, e.g. soil, sunlight
               3. Community: all the living organisms in an area
               4. Population: members of a single species in that area
               species: those organisms that can interbreed and produce fertile offspring
               5. Organism: a single individual
               6. Organ System: circulatory system, etc., within an individual
               7. Organs: part of an organ system (e.g. heart in circulatory, stomach in
               8. Tissues: groups of similar cells with related functions in a particular organ
               9. Cell: the smallest unit of living matter
               10. Organelles: subcellular structures (e.g. chloroplast) that have a specific
               11. Molecules: found within the cells and organelles, composed of atoms

       B. Living Organisms and the Environment
               1. Food Chain: a sequence of food transfer from trophic level to trophic level
                      a. Producers: organisms that make organic molecules from water,
                      carbon dioxide and inorganic materials. [e.g. plants (autotrophs) form
                      the base of the food chain]
                      b. Primary Consumers – herbivores (eat plants, algae and autotrophic
                      c. Secondary Consumers – carnivores (eat consumers below them)
                      d. Tertiary Consumers – eat consumers below them (e.g. eagle)
                      e. Detritivores –
                              1) derive their energy from detritus (dead material)
                              2) break down organic material into inorganic material
                              e.g. common mushroom
               2. Food Web – a network of interconnected food chains
               3. Energy is transferred and converted to different forms from organism to
               organism in the food chain.
C. Properties of Living Organisms
       1. All made of cells
       2. All reproduce
       3. All have growth: the addition of new material
       4. All have development: changes that take place as the organism matures
                a. examples
                       1) tadpoleadult frog
                       2) human babyadult
       5. All convert energy to usable forms
                a. energy – the capacity to do work
                b. metabolism – all chemical activities within an organism that sustain its
                       1) cellular respiration
                       2) photosynthesis
       6. All have cells that respond to stimuli
                a. stimuli – changes in the environment
                       1) external stimuli – occur outside the cell (e.g. light, sounds,
                       2) internal stimuli – inside the cell (e.g. blood pressure)
                b. homeostasis: a balanced internal environment for optimal functioning

D. Taxonomy – field of biology that deals with the naming and classifying of living
       1. Classification by
               a. characteristics
               b. relationship of that organism to other organisms
       2. Classification Hierarchy
       Memory Aid: Do Kings Play Chess on Funky Green Spaces?
       Scientific name for fireant: Solenopsis invicta (Genus species)
       3. Domains
               a. Archaea
                       1) live in extreme environments (e.g. Dead Sea)
                       2) single-celled organisms
                       3)  prokaryotic – lack a membrane-enclosed nucleus and
                       membrane enclosed organelles
              b. Bacteria
                     1) largest & most diverse domain
                     2) single-celled organisms
                     3) prokaryotic
                     4) many of them cause disease
              c. Eukarya
                     1) eukaryotic – have a membrane-enclosed nucleus and
                     membrane enclosed organelles
                     2) Four kingdoms in this domain
                             a. Protista – sometimes not called a kingdom; e.g. algae,
                             protozoans, etc.
                             b. Fungi – mushrooms, yeast, molds
                             c. Plantae – multicellular, e.g. trees, grasses
                             d. Animalia – multicellular, e.g. humans, dogs, cats

E. Scientific Method
Memory Aid: Owls Quickly Hide Peanuts Today
        1. Observation
                a. from previous studies
                b. from the scientist’s personal background
        2. Questions
                a. arise from observations
                b. usually are focused
                c. lead to a hypothesis
        3. Hypothesis
                a. possible answer
                b. most questions have more than one possible answer
        4. Predictions
                a. deductive reasoning
                b. based on testable hypothesis
                        1) ones that can be examined experimentally
                        2) ones that involve magic, etc. are not testable
        5. Testing
                a. experiments that test the hypothesis
                        1) experimental design
                                a. gather as much background info as possible
                                b. formulate focused hypothesis with yes-or-no answer
                                c. choose a quantitative (can be measured) variable to
                                d. do a controlled experiment, if possible
                                        1) 2 different tests done in parallel
                                                a. experimental test
                                                b. control test
                                        2) differ in only one factor
                                e. repeat experiments to ensure reliable results.
                                        1) use statistics – selected example
                                                a. average
                                                b. standard deviation
                                      2) sampling error – can occur if the sample size is
                                      too small.
                              f. compare results with hypothesis
                                      1) results may contradict hypothesis – it’s not
                                      2) consistent with hypothesis – may be correct,
                                      more tests needed for reliability
              b. results may disprove or support hypothesis
                      1) support is a very important word –difficult to prove anything
                      2) theories – hypotheses supported by lots of evidence
       6. Example of Scientific Method
              a. observation: flashlight won’t work
              b. questions
                      1) is the bulb burned out?
                      2) are the batteries dead?
              c. hypothesis
                      1) the bulb is burned out
              d. prediction
                      1) replacing bulb will fix problem
              e. test
              f. does not falsify because flashlight works

F. Evolution
        1. Basic Terminology
                a. evolution – change
                b. mutation – molecular change in an organism’s DNA (can be harmful,
                neutral, or beneficial; occur at random)
                c. adaptation – trait that helps an organism to survive & reproduce in
                particular environment
        2. Observations that led to the theory of evolution
                a. individuals of the same species show variation
                b. organisms produce more offspring than can survive
                c. organisms must compete in order to survive
                d. survivors in this competition live to reproduce & pass adaptation to
                e. over time, most of population will have that useful adaptation
        3. Natural Selection
                a. environmental factors select those organisms that are best able to
                survive and reproduce
                b. if a species can adapt, that species will survive – if not, it will become

G. Themes that Unify Biology
      1. cells – every organism’s basic unit of structure and function
      2. heritable information – the continuity of life depends on it
      3. emergent properties of biological systems – emerge as a result of interactions
      4. regulation – utilizes feedback mechanisms (e.g. sweating)
      5. interaction with the environment – living organisms’ interacting with both
other organisms and the non-living components of the environment
6. energy & life – all organisms work, and that work requires energy

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