The Science of Biology

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Chapter 1

• The Science of Biology

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Section 1-1What is Science
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Thinking about the Nature of Science

• What is science?
• What makes science powerful?
• What characteristics must something have in order
  for it to be science?
• How does one do science?

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What is Science? What is biology?

• Science an organized way of using evidence to
  learn about the natural world
• Biology the study of the living world

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How Scientists Work

• What are your ideas about what specifically makes
  science the most powerful method we have for
  understanding nature?

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How Scientists Work

• Using Scientific Method
• Ask a Question
• Form a Hypothesis
• Test the Hypothesis
• Analyze the Results
• Draw Conclusions
• Communicate Results

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Scientific Method

• The Scientific Method umbrella term for a
  variety of methods of study.
• All rigorous, systematic, evidence-based, and
  objective means of testing explanations of the
  natural world.
• Steps not the same order every time.

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Ask a Question

• Scientists form questions when they observe
  nature through their senses (sight, hearing,
  touch, smell)
• Examples
• Some peaches are juicy and sweet. Others are
  spongy with very little flavor.
• What makes some peaches juicier than others?
• My neighbor has thick, green grass. Mine is brown
  in spots and is thin.
• What does grass need to be healthy?

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Ask a Question Practice

• Make observations and form a scientific question
  about the pictures below.

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Form a Hypothesis

• Hypothesis a proposed explanation for a set of
  observations or possible answer to a question
• Must be testable, or its not scientific
• Write the hypothesis as a clear statement, do not
  say I think that .
• ATTENTION - It is okay for your hypothesis to be
  wrong! Never change your hypothesis after an
  experiment to make it correct.
• Prediction what you expect to observe. The
  data the experiment will produce if the
  hypothesis is correct
• Can be written as an If the hypothesis is
  correct, then statement.

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Form a Hypothesis Example

• Hypothesis Apples develop thicker skins as a
  defense against cold temperatures.
• Prediction If apples are exposed to cool
  temperatures, then they will have thicker skin
  than other apples.

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Form A Hypothesis Practice

• Write a possible hypothesis and prediction for
  each of the following observations.
• The plants in Mr. Smiths living room are large,
  healthy and green but the plants in Mr. Smiths
  dining room are small and yellowish in color.
• All of the fish in the classroom fish tank are
  healthy except for the algae eaters that keep
  dying.

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Test the Hypothesis

• Whenever possible, an experiment should be
  designed to have only ONE variable that is
  changed at a time. (AKA Controlled Experiment)
• Controlled Variable/s the variable/s that are
  purposely kept the same
• Manipulated Variable the ONE variable that is
  deliberately changed (also called independent)
• Responding Variable the variable that is
  observed and that changes in response to the
  manipulated variable (also called dependent)
• Experimental Group the group in which the
  manipulated variable is changed
• Control or Control Group the group used as a
  standard for comparison for the experimental group

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Test the Hypothesis Practice

• Hypothesis Tomato plants given fertilizer will
  produce more tomatoes than plants that are not
  fertilized.
• Plant A Plant B
• Both plants are given the same soil, amount of
  water and sun, temperature, pot size, and growth
  time.
• Plant B is fertilized once a week.
• What are the controlled variables, the
  manipulated variable, and the responding
  variable?
• Which is the control and the experimental group?

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Answers

• Controlled Variables soil, amount of water and
  sun, temperature, pot size, and growth time
• Manipulated Variable fertilizer
• Responding Variable of tomatoes
• Control Plant A
• Experimental Group Plant B

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Why change only one variable?
Plant B 7 hours of sunlight per day l L of water
every 2 days gallon sized pot 35C for 9
weeks fertilized once a week
Plant A 5 hours of sunlight per day l L of water
every 4 days quart sized pot 30C for 6 weeks no
fertilization
Cant tell!

• Why did plant B grow more tomatoes?
• Its the only way to know which manipulated
  variable caused the responding variable to
  change.

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Test the Hypothesis Practice

• Describe why the experiment below is poorly
  designed. Write a prediction for the hypothesis
  and then re-design the experiment to make it
  better. Identify all variables and groups.
• Hypothesis Bacteria exposed to antibiotics will
  be killed.

Plate B Stored in incubator (35 C) Given
ampicillin Stored in dark Given nutrients
Plate A Stored on counter (22 C) Given
penicillin Stored in light Not given nutrients
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Analyze the Results

• All experimental data must include units.
  (examples 9cm, 20sec, 98C)
• Tables and graphs are used to represent data and
  must be labeled with units and titles.

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Analyze the Results Example

• Notice the table below has units and clear
  labels.

Effect of Storage Temperature on Seed Germination Effect of Storage Temperature on Seed Germination Effect of Storage Temperature on Seed Germination Effect of Storage Temperature on Seed Germination
Storage Temperature Inside 68F Outside 25F Outside 25F
Germinated Seeds 0 80 85
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Representing Data in Graphs
Effects of Storage Temperature on Seed Germination
100 80 60 40 20 0





Germinated Seeds ()
- Inside 68F
- Inside 25F
- Outside 25F
Storage Temperature F
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Analyze the Results Practice

• Add to the data table and graph to improve them.
• Hypothesis Caffeine improves muscle performance.
• Prediction Caffeinated frogs will jump farther
  than uncaffeinated frogs.
• Results Frogs given caffeine jumped 27cm and
  frogs not given caffeine jumped 20 cm.

Frog not given caffeine Frog given caffeine
Distance of jump 20 27
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Table needs units, labels, and title.
Graph needs a title, labels on X and Y axis, and
a key.
Effect of Caffeine on Frog Jumps
Effect of Caffeine on Frog Jumps Effect of Caffeine on Frog Jumps Effect of Caffeine on Frog Jumps
Amount of Caffeine No Caffeine Caffeine
Distance of jump 20cm 27cm
Distance of jump (cm)
Amount of Caffeine
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Table needs units, labels and a title.
Graph needs a title, labels on X and Y axis, and
a key.
Effect of Caffeine on Frog Jumps Effect of Caffeine on Frog Jumps Effect of Caffeine on Frog Jumps
Amount of Caffeine No Caffeine Caffeine
Distance of jump 20cm 27cm
Effect of Caffeine on Frog Jumps
Distance of jump (cm)
Uniform scale every line stands for exactly 5
cm, no skips
Amount of Caffeine
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Choosing Bar vs Line Graphs

• Bar graph Used for groups/categories, Line
  graph Comparing two number scales
• Manipulated variable on X-axis, responding
  variable on Y-axis

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Graph Examples

• Number of students per town what kind of graph,
  bar or line?

Town of Students
Canton 9
Stoughton 2
Norwood 1
Westwood 4
Dedham 3
Milton 2
Randolph 1
Sharon 1
Hyde Park 1
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Graph Examples

• Number of students at different heights what
  kind of graph, bar or line?

Height (cm) of Students
150 2
151 2
152 3
153 6
154 5
155 3
156 1
157 1
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Bar or Line Graph?

• Number of American Thrushes living in each of
  five forests
• 100 students choices for their favorite lunch
• Comparing the number of chromosomes to the number
  of genes
• The number of mates attracted by red vs yellow vs
  blue-beaked parrots
• The growth of a seedling (days old vs height)

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Draw Conclusions

• Conclusion a final summation of experimental
  results
• A conclusions main purpose is to evaluate your
  initial ideas (hypothesis prediction) using
  your data
• A conclusion should do the following

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Draw Conclusions(Add your own notes)

• State the purpose in your own words.
• Summarize the scientific idea the lab is about,
  and define any vocab words.
• Restate the hypothesis and prediction, not
  copying exactly how they were already written.
• Summarize (1-2 sentences) the procedure.
• State whether the results support or refute the
  hypothesis/prediction.
• Support the evaluation you made in step 5 with
  specific evidence (data).
• The average height in group A was 2 cm higher
  than group B. Specific. Group A
  grew more. Not specific.
• Give a final concluding statement.
• If your hypothesis was supported, summarize that.
• If it was refuted, give a new and improved
  hypothesis.

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Draw Conclusions Example

• Label the paragraph with numbers, marking where
  each of the 7 steps occurs
• The experiment was designed to test whether
  caffeine would increase the distance frogs could
  jump. Caffeine is a stimulant. Stimulants are
  psychoactive drugs, meaning that they affect the
  nervous system. Jumping involves the nervous and
  muscular systems, so its possible that caffeine
  could affect jumping. It was hypothesized that
  caffeine improves muscle action, and it was
  predicted that the more caffeine a frog has, the
  farther it will jump. To test this, some frogs
  were given caffeine and others were not, and the
  lengths of their jumps were measured.
• The results supported the hypothesis and
  prediction, showing that frogs given caffeine
  jumped an average of 7cm farther than frogs that
  were not given caffeine. Caffeine does indeed
  increase the distance that frogs can jump.

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Draw Conclusions Practice

• Examine the hypothesis and experimental results
  below, and write an appropriate conclusion.
• Hypothesis Carrots require high nitrogen levels
  for best growth.
• Results

Effects of Nitrogen Levels on Carrot Growth Effects of Nitrogen Levels on Carrot Growth Effects of Nitrogen Levels on Carrot Growth Effects of Nitrogen Levels on Carrot Growth
Level of Nitrogen None Low High
Average Carrot Length 6 in. 10 in. 4 in.
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Communicate Results

• Scientists always report their results through
  journals and scientific papers.
• Allows others to repeat the investigation,
  skeptically evaluate the validity of the results,
  can lead to further questions and
  investigations.

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Scientific Language
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Scientific Language

• The scientific process has a language of its own.
• Sometimes, this language diverges from
  conversational English.
• Science words can be different from English
  words even when they look exactly the same.

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Scientific Language

• For example the words for different kinds of
  scientific outcomes and models.
• In English, an observation is
• In Science, an observation is

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Scientific Language

• Observation (Science definition) A data point
  gathered by one of the five senses.
• An example of an observation in science After
  adding solution A to solution B, the mixture has
  a sharp sour smell.

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Scientific Language

• Fact

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Scientific Language

• Fact (Science definition) An observation that
  has been made repeatedly.
• Example Two negative poles move away from each
  other.

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Scientific Language

• Law

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Scientific Language

• Law (Science definition) A mathematical
  description of patterns in a relationship between
  two quantities.
• Example p q 1, (p q)2 (Hardy-Weinbergs
  Law)

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Scientific Language

• Theory

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Scientific Language

• Theory (Science Definition) A powerful
  explanation of numerous natural phenomena.
• Example Matter is made up of atoms, properties
  of matter come from atomic behavior (Atomic
  theory)

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Section 1-3Studying Life
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Characteristics of Living Things

• made up of cells
• reproduce
• DNA
• grow and develop
• need materials and energy
• respond to the environment
• maintain a stable internal environment
  (homeostasis)
• evolve (as a group, change over time)

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Living things are made up of cells.

• Cell a collection of living matter
  enclosed by a barrier separating
  the cell from its surroundings
• Cells are the smallest units of life in all
  organisms.
• Unicellular organisms single celled
• Multi-cellular organisms composed of more than
  one cell

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Living thingsreproduce.

• Reproduction process where organisms produce
  new organisms or offspring
• Sexual Reproduction two cells from different
  parents unite to produce first cell of new
  organism
• Asexual Reproduction a single-celled organism
  divides in half to form two new organisms OR a
  portion of an organism splits off to form a new
  organism

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Living things contain DNA.

• DNA (deoxyribonucleic acid) carries directions
  for inheritance.
• DNA determines the inherited traits of every
  organism on Earth.

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Living things grow and develop.

• Growth getting larger in size
• Unicellular cell gets bigger
• Multicellular create more cells
• Development changes that occur during an
  organisms lifetime (life cycles)

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Living thingsneed materials and energy.

• Metabolism organisms chemical reactions
  building or breaking down materials
• Organisms vary in how they obtain energy

• Autotrophs capture energy from sun and convert
  it into food energy
• Heterotrophs must take in food for energy

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Living things respond to the environment.

• Organisms live in constantly changing
  environments (living and nonliving parts).
• Organisms respond or change to cope.

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Living thingsmaintain internal balance.

• Organisms maintain stable internal conditions
  (homeostasis) despite fluctuations in
  environment.
• temp, water content and food intake

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Living things evolve over time.

• Populations of organisms evolve (change over
  time).
• Natural selection organisms that have certain
  favorable traits are better able to successfully
  reproduce than organisms that lack these traits