The Science of Biology

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The Science of Biology

• Chapter 1
• Pgs. 2 33

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1-1 What is Science?
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The Goal of Science

• Investigate and understand nature
• Explain events in nature
• Use the explanations to make useful predictions

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What make Science different?

• Deals only with the natural world
• Collects and organizes information in a careful
  and orderly way
• looking for patterns and connections between
  events
• Proposes explanations that can be tested by
  examining evidence.

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What is Science?

• Science an organized way of using evidence to
  learn about the natural world.
• Refers to a body of knowledge that has been
  gathered over the years using this process.

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3 Parts of Science

• Observations using one or more of the senses to
  gather information
• The information or evidence gathered through
  observations is called data.
• Quantitative observations involve numbers, i.e.
  counting and measuring.
• Qualitative observations involve characteristics
  that cannot be measured or counted, i.e. what you
  see (texture and color) does not use experiments

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3 Parts of Science

• Inferences logical interpretations based on
  prior knowledge and experience.
• Hypothesis possible explanations for a set of
  observations or answers to specific questions.
• Only useful if it can be tested

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1-2 How Scientists Work
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Designing an Experiment

• State the Problem
• Form a Hypothesis
• Set Up a Controlled Experiment to test the
  hypothesis
• Controlled experiment - an experiment in which
  only one variable is changed at a time, while all
  other variables stay the same
• Independent variable (manipulated variable) the
  variable changed in the experiment
• Dependent variable (responding variable) the
  variable that is observed and changes in response
  to the independent variable (manipulated variable)

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Designing an Experiment (continued)

• Record and Analyze Results
• Written records of observations, or data
• Can be handwritten and kept in notebooks or
  journals, may consist of drawings, or may be
  stored online.
• Draw Conclusion(s)
• Data is used to evaluate the hypothesis and draw
  a conclusion.
• Does your data support or reject your hypothesis?
  And why?

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Publishing and Repeating Investigations

• You contribute to science (the body of knowledge)
• The experiment is repeated to validate it.
• Other scientists repeat their work to see if the
  results are the same as the results originally
  reported.

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Redi and the Scientific Method

• Stating the Problem
• Maggots seem to show up on meat. How do new
  living things come into being?
• Forming a Hypothesis
• Spontaneous generation belief that life arises
  from nonliving things.
• Flies produce maggots which are too small to see.
• Setting Up a Controlled Experiment
• Redi believed that keeping flies away from the
  meat would prevent the appearance of maggots.
  (see Figure 1-8 on p. 9)
• Recording and Analyzing Results
• Redis results showed later generations that
  maggots appeared on the meat in the controlled
  jars, while none were on the jars covered by
  gauze.
• Drawing Conclusions
• Maggots form only when flies come in contact with
  meat. Spontaneous generation of maggots did not
  occur.

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Redis Experiment
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Testing of Redis Experiment (see Fig. 1-10 on
p. 11)

• Needham
• Performed experiment to disprove Redi by heating
  a sealed bottle of gravy.
• He claimed the heat killed any living thing in
  the gravy.
• When microorganisms were found in the gravy
  several days later, he claimed they can only
  have come from juice of the gravy.

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Testing of Redis Experiment (see Fig. 1-10 on
p. 11)

• Spallanzani
• Repeated Needhams work but sealed one flask
  immediately after heating both flasks.
• After a few days, the flask left unsealed
  contained microorganisms, while the sealed one
  did not.
• He concluded that nonliving gravy is not produce
  living things.

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Testing of Redis Experiment (see Fig. 1-11 on
p. 12)

• Pasteurs Test of Spontaneous Generation
• His experiment showed that boiled broth would
  remain free of microorganisms even if air was
  allowed in, as long as dust and other particles
  were kept out.
• His work led to the study of infectious diseases.

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How a Theory Develops

• Theory is a well-tested explanation that
  unifies a broad range of observations.
• No theory is considered to be absolute truth.
• It is revised or replaced as new evidence is
  uncovered.
• Law facts of nature that are generally known to
  be true
• Ex. Gravity, Newtons Laws of Motion

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1-3 Studying Life

• Biology bios life, logos study

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Characteristics of Living Things

• Composed of units called cells
• Ability to reproduce
• Based on a universal genetic code
• Grow and develop
• Obtain and use materials and energy
• Respond to their environment
• Maintain a stable internal environment
• As a group, able to change over time

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Made Up of Cells

• Cell - smallest units of an organism that can be
  considered alive.
• collection of living matter enclosed by a barrier
  that separates the cell from its surroundings
• Unicellular organisms consist of a single cell.
• Example bacteria
• Multicellular organisms consist of two or more
  cells.
• Example dogs, insects, humans

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Reproduction

• Sexual reproduction two cells from different
  parents unite to produce the first cell of the
  new organism.
• Asexual reproduction the new organism has a
  single parent
• Budding
• Fission

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Based on a Genetic Code

• Offspring resulting from asexual reproduction
  have exactly the same traits as the parent.
  (identical)
• Offspring resulting from sexual reproduction
  differ from their parents in some way.
• The traits of all organisms is determined by
  their genetic code, consisting of DNA
  (deoxyribonucleic acid).

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Growth and Development

• Every type of organism has a distinct type of
  life cycle.
• Growth is the increase in size.
• Development occurs when the cells of the
  organism increase in number and become different.

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Need for Materials and Energy

• Organisms need energy and a constant supply of
  materials to grow, develop, and reproduce.
• Metabolism the combination of chemical
  reactions through which an organism builds up or
  breaks down materials as it carries out its life
  processes.
• All the chemical reactions that take place in an
  organism

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Response to the Environment and Maintaining
Internal Balance

• Organisms live in a constantly changing
  environment.
• In order to survive, organisms must respond to
  those changes.
• Homeostasis the process by which an organism
  keeps their internal conditions relatively
  stable.
• Stimulus and Response
• Stimulus any condition in the environment that
  requires an organism to adjust
• Response the reaction to a stimulus

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Evolution

• Evolve change over time the gradual
  accumulation of adaptations over time
• The result is present diversity of live
• Dogs there are many types of dogs that perform
  different functions but they are all dogs

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Branches of Biology

• Biology can be divided into branches or divisions
  based on the type of organism being studied.
• Zoologist study animals
• Botanists study plants
• Ethologists study animal behavior
• Paleontologists study life that was in the past
• Biology can be divided into levels of organization

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Levels of Organization

• Molecules groups of atoms
• Cells consists of a group of molecules smallest
  functional unit of life
• Tissues consists of a group of cells working
  together
• Organs consists of a group of tissues working
  together
• Organ systems a group of organs working together

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Levels of Organization

• Organism a group of organ system working
  together
• Population group of organisms of the same type
  living in the same area
• Community different populations that live in an
  area
• Ecosystem a community and its nonliving
  surroundings
• Biosphere the Earth consisting of all ecosystems
• Figure 1-21 pg. 21

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1-4 Tools and Procedures
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A Common Measurement System

• Metric system used to collect data and perform
  experiments.
• Aka SI units (International System of
  Measurements)
• Based on multiples of 10.
• Common metric units
• Length meter
• Volume liter
• Mass gram
• Time seconds
• Temperature degrees Celsius

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Analyzing Biological Data

• Tables

• Graphs

http//library.thinkquest.org/5090/test.htm
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Microscopes

• Microscopes devices that produce magnified
  images of structures that are too small to see
  with the unaided eye.
• Light microscopes produce images by focusing in
  visible light rays.
• Electron microscopes produce magnified images by
  focusing beams of electrons.

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Light Microscopes

• Most commonly used
• Produce clear image 1000x the original size
• Compound light microscopes allow light to pass
  through a specimen and use two lenses to form an
  image
• Dead or living specimens can be viewed

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http//www.indigo.com/software/gphpcd/zoo1-4.html
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Electron Microscopes

• Uses a beams of electrons to focus on specimens
• Can magnify images that are 1000x smaller than
  those of a light microscopes
• Images have no color
• Cannot be used on living specimens
• Transmission electron microscope (TEM)
• Scanning electron microscope (SEM)

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http//path.upmc.edu/cases/case55/em.html
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Working Safely in Biology

• Safety is supreme in all biological studies.
• Refer to Appendix B for Safety rules and symbols.