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Notes Chapter 1 The Science of life

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									                            Chapter 1 The Science of life

1. List 6 unifying themes of biology – the study of life.
A. Cell Structure and Function
   1. All organisms are made up of cells.
          a. Some are unicellular, some multicellular.
          b. Cells of multicellular organisms underwent differentiation.
                 i. Cells are small but highly organized.
B. Stability and Homeostasis
   1. All organisms have a way of maintaining stable internal conditions. This stable level
   of internal conditions is called homeostasis.
C. Reproduction and inheritance – sexual and asexual – DNA and genes
   1. All organisms reproduce.
          a. This is the process by which organisms transmit their hereditary information
          to their offspring.
                   i. Hereditary information = DNA (deoxyribonucleic acid).
                        a) A gene is short segment of DNA that contains the instructions for
                           the development of a single trait.
                        b) Sexual reproduction: genetic information from 2 parents is
                           combined to form a new organism.
                        c) Asexual reproduction: one cell gives rise to 2 new identical cells
                           (no combining of DNA).
D. Evolution – change over time by natural selection
   1. Populations of organisms evolve, or change, over generations. Evolution helps
   explain how many kinds of organisms came into existence.
   2. Evolution is generally thought to happen through the process of natural selection.
          a. Natural Selection: organisms with favorable traits live longer and are better
              able to reproduce than organisms that don’t have those traits.
                 i. Evolution via natural selection generally comes about because of
                     competition for resources.
E. Interdependence of Organisms – ecology and ecosystems
   1. Ecology: the study of the interactions of organisms with one another and with their
   environment.
          a. Specific environmental communities are called ecosystems.
          b. The stability of the environment depends on the organisms in the
              environment.
          c. The stability of the organisms depends on the availability of food, water,
              nutrients, and gases available to those organisms.
F. Matter, Energy and Organization – complex organisms – autotrophs and heterotrophs
   1. Living things need a constant supply of energy.
   2. All energy comes from the sun, either directly or indirectly.
          a. Photosynthesis – the process of capturing energy from the sun and using it to
              make food. This is done by autotrophs.
          d. Heterotrophs are organisms that must consume other things, such as
              autotrophs, to get their energy.
2. List 7 characteristics of life and describe the main difference between the structure of a
living thing and that of a nonliving thing.
A. Organization
    1. Organisms are highly organized and contain many complex chemical substances
    2. atoms, molecules, organelles, cell, tissue, organ, organ system, organism -
       populations - communities - ecosystems
B. Cells
    1. All living organisms are made up of one or more cells
    2. Fundamental units of life
C. Organisms use energy - Energy = capacity to do work
    1. Metabolism - the sum of all chemical reactions that occur in a cell (i.e. the
    breakdown of food for energy, or the use of the energy to make things happen in your
    body).
    2. Ultimate source of energy for life on earth is the sun through photosynthesis
D. Homeostasis - balance - maintenance of a stable level of internal conditions
E. Growth
    1. Cell division - Either via mitosis or meiosis.
    2. Organisms have a definite form and a limited size
    3. Development - the process by which an adult organism arises = Done via cell
       division and cell differentiation (specialization)
    4. Organisms have a limited life span
F. Reproduction - Necessary for the survival of the species. Sexual or asexual.
G. Respond to their environment - helps organism survive
    1. Adaptations
       a. Groups of organisms change over time
       b. Adaptations are modifications that make an organism suited to its way of life
       c. Natural selection is process by which species becomes modified over time

3. Explain how organisms get the energy they need to survive.
      A. photosynthesis – the capture of the sun’s energy and conversion to usable energy
      for living things
      B. autotrophs – organisms that obtain their own energy by making their own food
      some organisms (plants) convert water and carbon dioxide into sugars and starches
      C. photoautotrophs – use light energy like photosynthesis
      D. chemoautotrophs – use energy from inorganic substances such as hydrogen
      sulfide, ammonia and nitrogen compounds
      E. heterotrophs – organisms that must eat other organisms to get energy - either
      auto or heterotrophs
      F. metabolism – sum of all chemical processes that occur in an organism - some
      substances are broken down to yield energy for vital processes while other
      substances, necessary for life, are synthesized
4. Describe how a living thing is organized
A. Organization – molecular and cellular levels – atoms, molecules, organelles, cell, tissue,
   organ, organ system, organism
B. Followed by higher levels of organization – populations, communities, ecosystems,
   biosphere, Earth, planets, solar system, galaxies, universe

5. Explain why all living things on earth are not yet well understood
A. Biodiversity
   1. Measure of all living organisms in an area
   2. There is a large number of unidentified organisms because of difficulty in finding
   them deep in the rainforests or deep ocean

6. Define and give examples of observing, measuring, organizing, and analyzing data,
inferring and modeling.
A. Observing – using five senses – sight, hearing, smelling, touch, tasting
B. Measuring – quantitative data – can be measured in numbers
C. Sampling – must be large and random to get a good cross section of the population
D. Organizing data – graphs, charts, tables, maps
E. Analyzing data – process of determining if the data is reliable and if it supports the
   hypothesis or not
   1) Use statistics
   2) Compare data with other studies
   3) Determine possible sources of error
F. Modeling – model is an explanation supported by data
G. Inferring – inference is a conclusion made on the basis of facts rather than on direct
   observation

7. Explain the relationship between hypothesizing, predicting, and experimenting.
A. Hypothesizing
   1. Hypothesis – statement that explains observations that can be tested
       a. can be supported by evidence
       b. can not be proven without a doubt
   2. forming a hypothesis – collect data that does or does not support the statement
   3. predicting – statement made in advance that states the results – in the form of “if-
         then”
       a. two approaches to developing and testing hypotheses :
            i. inductive – gather empirical data and from it make generalizations
            ii. deductive – develop a general idea about a phenomenon, perform
      experiments, and from them make specific predictions that can be tested again
B. Experimenting – process of testing a hypothesis
    1. conducting a controlled experiment
       a. control group – standard of comparison with another group identical except one
          factor – the base group – not altered
       b. experimental group – group you changed one factor of from control group
      c. independent variable – the one that is manipulated
            i. factor that is different in control and experimental groups
           ii. the material one is working with during an experiment – the control
          iii. goes on the X axis
      d. dependant variable – the one that results from changes in the independent
            i. driven by or results from the independent variable
           ii. is what is being tested
          iii. changes with the independent variable
          iv. goes on the Y axis
C. In short = order is make observations, write a hypothesis, make a prediction, then
      conduct a controlled experiment

8. Explain why good communication is so important in science
A. Implementing Scientific Methods
   1. Problem solving – more heads are better than one
   2. Communicating – sharing of results – publishing in scientific journals – others can
      also test the hypothesis

9. Describe the methods that scientists use in their work.
A. Scientific Method
   1. Observing
      a. The act of noting or perceiving objects or events using the senses.
      b. Careful records must be kept of all observations in order to draw a conclusion or
         come to an answer.
   2. Asking a Question
      a. Observations of the world usually raise questions.
   3. Collecting data
   4. Hypothesizing
      a. A hypothesis is an explanation that might be a true statement.
      b. A prediction is the expected outcome of a test, assuming the hypothesis is correct.
   5. Experimenting – testing a hypothesis
      a. Data is needed.
      b. Controlled experiment- a controlled experiment always has a control group and
         an experimental group.
   6. Drawing Conclusions
      a. Does the data support or reject the hypothesis (found out by analyzing the data).
      b. Model: a visual, verbal, or mathematical explanation supporting the data.
      c. Inference: a conclusion made on the basis of facts or premises rather than on
         direct observations.
      d. Inferences are not directly testable.
   7. Implementing Scientific Methods
       a. Publishing Results
       b. Once a scientist completes an experiment, the results are often published for the
          scientific community to review.
       c. Many hypotheses that have been tested and confirmed many times by scientists
          eventually become a THEORY.
       d. A SCIENTIFIC LAW is a description of a natural phenomenon or principle that
          invariably holds true under specific conditions and will occur under certain
          circumstances.

10. Compare light microscopes with electron microscopes in terms of magnification
    and resolution.
A. Microscopes – instrument that produces and enlarged image of an object
   1. magnification – increase of an object’s apparent size
   2. resolution – power to show details clearly
   3. light microscopes – uses light of produce an image – used to view living things
      a. power of magnification – factor of enlargement/magnification 10x, 100x, 1000x
          1. power of magnification of strongest objective lens X the power of
             magnification of the ocular lens
          2. limited by the characteristics of light – wavelengths
   4. electron microscopes – uses a beam of electrons to produce an image – cannot view
      living things
      a. transmission electron microscope – transmits a beam of electrons through a
          thinly sliced specimen and onto a screen
      b. scanning electron microscope – creates a 3-D image by spraying a whole
          specimen with a fine metal coating then a beam of electrons is passed over it and
          then projected onto a fluorescent screen

11. Explain the advantage of the Systeme International d’unites
A. standard system of measurement called International System of Measurement (SI)
   1. The SI unit system consists of seven base units, with a number of other units derived
   from those foundations.
      a) examples = meter, kilogram, second, Kelvin, mole
   2. Derived units – produced by the mathematical relationship between two base units
      or between two derived units – used to measure surface area and velocity
      a) example = velocity is m/s (meters per second)
      b) using the base unit of length and the base unit of time to determine the length
         traveled over a given period of time.
      c) There are 7 fundamental base units in SI that describe length, mass, time, and
         other quantities:
   SI Base Units
Base Quantity                      Name       Abbreviation
Length                             Meter      m
Mass                               Kilogram   kg
Time                               Second     s
Electric current                   Ampere     A
Thermodynamic temperature          Kelvin     K
Amount of substance                Mole       mol
Luminous intensity                 Candela    cd

   Some SI prefixes
Prefix                      Abbreviation Factor of base
                                         unit
Giga                        G            1, 000, 000, 000
Mega                        M            1, 000, 000
Kilo                        k            1, 000
Hecto                       h            100
Deka                        da           10
Deci                        d            0.1
Centi                       c            0.01
Milli                       m            0.001
Micro                                   0.000001
Nano                        n            0.000000001
Pico                        p            0.000000000001

SI derived units often used in biology
Derived quantity                         Name                       Abbreviation
Area                                     Square meter               m2
Volume                                   Cubic meter                m3
Mass density                             Kilogram / cubic meter     kg/m3
Specific volume                          Cubic meter / kilogram     m3/kg
                                                                    o
Celsius                                  Degree Celsius               C

Other acceptable SI units
Name                          Abbreviation    Value in SI units
Minute                        min             1 min = 60 s
Hour                          h               1 hour = 60 min = 3, 600 s
Day                           d               1 d = 24 h = 86, 400 s
Liter                         L               1 L = 1 dm3 = 0.001 m3
Metric ton                    t               1 t = 1, 000 kg
                       Biology Chapter 1 Review – The Science of Life

 Biology is the study of life, ranging from the study of unicellular organisms to the study of
  the global interactions among millions of organisms.
 Six themes serve to unify the study of biology: cell structure and function; (2) stability and
  homeostasis; (3) reproduction and inheritance; (4) evolution; (5) interdependence of
  organisms; and (6) matter, energy, and organization.
 The cell is the basic unit of life. Organisms may be unicellular or multicellular.
 Living things maintain a stable level of internal conditions, called homeostasis.
 Reproduction involves the transmission of hereditary information from organisms to their
  offspring.
 Populations of organisms evolve over generations primarily by a process called natural
  selection.
 Organisms interact in important ways with each other and with their environments.
 Living things have highly organized structures that are maintained by a constant input of
  energy.
 Autotrophs obtain energy by making their own nutrients.
 Heterotrophs obtain energy from the nutrients they obtain from their environment.
 Living things are composed of cells.
 Living things are more highly organized than nonliving structures.
 Living things use energy in a process called metabolism.
 Living things have several mechanisms that help them maintain stable internal conditions.
 When living things grow, their cells enlarge and divide.
 Living things reproduce, producing offspring similar to themselves.
 There is a great deal yet to be learned about the living world.
 Scientific investigations generally begin with observation.
 Methods scientists use in their work include observing, (2) asking a question, (3) collecting
  data, (4) hypothesizing, (5) experimenting, and (6) drawing conclusions.
 A hypothesis is a statement that explains observations and that can be tested.
 In a controlled experiment, the experimental group is identical to the control group except
  for one factor called the independent variable.
 Communication is very important in science because scientists build on the work of others.

Vocabulary list

Autotroph                         Evolution                          Organism
Biology                           Experiment                         Photosynthesis
Compound light microscop          Experimental group                 Power of magnification
Control group                     Heterotroph                        Prediction
Controlled experiment             Homeostasis                        Resolution
Dependent variable                Hypothesis                         Sampling
Derived unit                      Independent variable               Scientific method
Development                       Inference                          SI
Differentiation                   Magnification                      Theory
Ecology                           Metabolism
Ecosystem                         Model
Electron microscope               Observation

								
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