The Science of Life

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The Science of Life
Chapter 1
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• 1.1 What is science?
• The goal of science is to
• investigate and understand the natural world
• explain events in the natural world
• make useful predictions

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• Science is different from other endeavors in
  that
• only deals with natural world
• collects information in orderly way (scientific
  method)
• Investigates hypothesis that can be tested

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• In other words.science is an organized way of
  using evidence to draw conclusions.
• Thinking like a scientist..
• Observation the process of gathering
  information through our senses

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• Data is the information we gather from our
• observations.
• 2 kinds -
• qualitative cant easily
  measure
• ex. the bird has a
  red head
• quantitative can measure
• ex. There are 7 bird on the
  feeder

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• Data collected is used to make a
• hypothesis
• a hypothesis is a possible answer to a
• question
• you have to be able to test a
  hypothesis to
• gather data
• Even if data does not support a
  hypothesis
• it is o.k.!
• data is data, and can be used to rule out
  or rule in causes and can redirect ideas.

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• Last thoughts about science..
• Science/biology has a lot of facts. However, is
  it not set in stone - unchanging
• Science is a way of knowing
• Science is an ongoing process
• Science is always changing as new
  questions/answer are found.
• This is the fun part....and your job as
  scientists!
• Open the newspaper on any given day and there
• are hundreds of new discoveries.or ideas to be
• processed.

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• 1.2 How Scientists Work
• A. Scientific Method?
• 1. Form a hypothesis
• 2. Create a controlled experiment
• include only 1 manipulated variable
• - independent variable changed
  factor
• include a control group (no
  change)
• Observe only one responding
  variable
• - dependent variable

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• 3. Record quantitative data
• Draw conclusions
• Repeat experiment why?
• 6. Collaborate with others about work
• Develop a theory well tested hypothesis

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Figure 1-8 Redis Experiment on Spontaneous
Generation
OBSERVATIONS Flies land on meat that is left
uncovered. Later, maggots appear on the meat.
HYPOTHESIS Flies produce maggots.
Uncovered jars
Covered jars
PROCEDURE
Controlled Variables jars, type of
meat, location, temperature, time
Several days pass
Manipulated Variables gauze covering that keeps
flies away from meat
Responding Variable whether maggots appear
Maggots appear
No maggots appear
CONCLUSION Maggots form only when flies come in
contact with meat. Spontaneous generation of
maggots did not occur.
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• leafcutter ant

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• Redis hypothesis stated that life must arise
  from other living organisms, not non-living
  material.
• About 200 years after Redi, Louis Pasteur
  designed an experiment that supported Redis
  observations. Pasteurs work is an example of
  the collaboration between scientists (non
  directly in this case 200 yrs), and an example
  of the long process, with several repeating
  experiments, that science can take to develop
  theories.

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Pasteur his setup
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• 1. 3 Studying Life What is Biology?
• Biology is.
• The science of studying the LIVING world
• It's Alive!
• It's Alive 2!
• Living organisms share SEVERAL
• characteristics.

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• Living organisms
• 1. are made of cells

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• Living organisms
• 1. are made of cells
• 2. reproduce sexually (2 parents) or
• asexually (one
  parent)

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• Living organisms
• 1. are made of cells
• 2. reproduce sexually (2 parents) or
• asexually (one
  parent)
• 3. grow and develop

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• 4. Based on a genetic code
• - DNA

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• 4. Based on a genetic code
• - DNA
• 5. Obtain and use materials and energy
• Food, ATP, Photosynthesis.

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• 4. Based on a genetic code
• - DNA
• 5. Obtain and use materials and energy
• Food, ATP, photosynthesis
• 6. Respond to their environment

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• 4. Based on a genetic code
• - DNA
• 5. Obtain and use materials and energy
• Food, ATP, photosynthesis
• 6. Respond to their environment
• 7. Maintain a stable internal environment.
• homeostasis. organism maintain balance

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• 8. As a group, living organisms change over time
• ..organisms evolve!

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• Scientists can study biology on many levels
• From the smallest units to the biggest..
• molecules of life DNA, carbs, proteins,
  fats
• cells smallest unit of life
• groups of cells tissues, organs, systems
• organisms individual living thing
• see page 21 for a great picture of this

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• population group of similar organisms
• community several pops in an area
• ecosystem community and the non-living
• surroundings
• biosphere the part of the earth that
  contains
• all ecosystems
• see page 21 for a great picture of this

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Diagram shows the biggest classification of
life..the WORLD! all the way down to tiny
molecules.
Levels of Organization of living systems
Biosphere
The part of Earth that contains all ecosystems
Biosphere
Ecosystem
Community and its nonliving surroundings
Hawk, snake, bison, prairie dog, grass, stream,
rocks, air
Community
Populations that live together in a defined area
Hawk, snake, bison, prairie dog, grass
Population
Group of organisms of one type that live in the
same area
Bison herd
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Levels of Organization continued
Section 1-3
Organism
Individual living thing
Bison
Tissues, organs, and organ systems
Groups of Cells
Nervous system
Brain
Nervous tissue
Smallest functional unit of life
Cells
Nerve cell
Groups of atoms smallest unit of most
chemical compounds
Molecules
DNA
Water
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• A. Metric System and biology
• decimal system based on units of 10
• meter standard unit of length
• 1 meter 100 centimeters (cm)
• 1 meter 1000 millimeters (mm)
• frog egg 1 mm (visible to
  eye)

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• A. Metric System and biology
• decimal system based on units of 10
• meter standard unit of length
• 1 meter 100 centimeters (cm)
• 1 meter 1000 millimeters (mm)
• frog egg 1 mm (visible to
  eye)

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• A. Metric System and biology
• decimal system based on units of 10
• meter standard unit of length
• 1 meter 100 centimeters (meter
  stick)
• 1 meter 1000 millimeters (mm)
• frog egg 1 mm (visible to
  eye)
• 1mm 1000 micrometers (um)
• human egg 100 um
• average bacterial cell 2
  um (.002 mm)
• 1 um 1000 nanometers
• virus -100 nm
• DNA 1nm

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how big is a cell? Animation Metric Unit of
mass kilogram examples Metric Unit of
volume liter examples
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• Microscope
• 1. Stereoscope Dissecting microscope
• a. used to see living specimens
• b. visible to the naked eye
• c. bugs, small worms

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• 2. Compound Light Scope cells, small organisms)
• a. live specimen.thin, often stained
• b. Light passes through and up lenses
• c. Magnifies clearly about 1000x - our
  
• school scopes - 400x

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Compound Light Microscope

• yeast cells
• onion cells
• cheek
• cells

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virtual microscope!
Compound Light Microscope 400x
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• Electron Microscope transmission scanning
• beams of electrons are passed through/over a
  specimen and produce a very detailed image of the
  inside of cells and 3-D images of the surface of
  specimens.
• cant view living specimens

Red blood cells
Plant cells dividing
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Exploring the Cell

• New technologies allow researchers to study the
  structure and movement of living cells in great
  detail.

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Electron Microscopes

• Electron microscopes reveal details 1000 times
  smaller than those visible in light microscopes.
• Electron microscopy can be used to visualize only
  nonliving, preserved cells and tissues.

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Electron Microscopes

• Transmission electron microscopes (TEMs)
• Used to study cell structures and large protein
  molecules
• Specimens must be cut into ultra-thin slices

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Electron Microscopes

• Scanning electron microscopes (SEMs)
• Produce three-dimensional images of cells
• Specimens do not have to be cut into thin slices

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Wet Mount Preparation

• A wet mount slide prep is used to prepare a
  specimen for viewing under a compound light
  microscope. It allows a specimen that needs to
  be wet/moist to be viewed accurately without
  drying out. It also makes it easier to see the
  specimen by flattening out the water drop that
  the specimen is in.