Chapter 2The Science of
Biology
What is Science?Science is derived from a Latin verb meaning “to
know.”
InquiryWhat is inquiry?A- People ask questions about what they
observe in nature and actively seek answers. Ex. Houseplants grow toward a light source.If we rotate the plant will its direction of growth
still go toward light source?What direction would the plant grow In the dark?
Observation and DataThe questions that drive scientific inquiry are
based on observations.Observation-Use of senses (vision or hearing) to gather
information.Data- Recorded observations.
Quantitative vs Qualitative Data
Quantitative:Collecting data with numbers.Ex. Measurements.Qualitative: Writing with descriptions instead of measurements.
Pictures and drawings.Ex. Jane Goodall spent decades recording her observations of chimpanzee behavior in the jungle.
Quantitative vs Qualitative?
1. The lion woke up at sunrise everyday and cleaned his paws. This lion mated with the females lions.
A. Qualitative
Quantitative vs Qualitative?
2. There were 7 ant hills in the grass.The alligator grew 1 inch every week.
A. Quantitative
InferenceInference- A logical conclusion based on
observations and prior knowledge.Ex. What can you infer if you hear a doorbell
ring?
A. When a doorbell rings you infer that someone is at the door.
Observation:Four place settingNo drinking cupsEmpty plates Infer:Four peopleFood is somewhere hiddenDrinks will be from cans
What can you observe from this graph?
Girls start out taller than boys Boys eventually are taller than girls
2.2 Hypothesis “The Scientific Method”
Hypothesis- Is a suggested answer to a well-defined scientific question or an explanation on trial.
Scientific Method
ScenarioIt’s late at night and you hear thunder and rain.
Wind begins to pick up and you see a tree fall. Your power goes out. What do you reach for?
A. Flashlight
The flash light does not work!
ScenarioWhat is our observation?Flashlight does not work.What is our question?What’s wrong with the flashlight?What is our hypothesis?The batteries are dead.
ScenarioWhat is our prediction?If the batteries are dead and we replace them,
the flashlight will work.What is our test?Replace the batteries.
Scenario Summary
Designing a Controlled Experiment
Variable- A condition that can differ within the
experiment.Controlled Experiment-An experiment that tests the effect of a single
variable.
Case Study SnakesMany poisonous animals are brightly colored
with distinctive patterns. There are also mimics.Coral snake (poisonous) Scarlet king snake (Not
p)
What is the function of mimicry?
What kind of experiment can you design to find the function of mimicry?
Observation?Both types of snakes have red, yellow, and black
rings.Question?What is the function of the kingsnakes’ mimicry of
coral snakes?Hypothesis?Mimicry of coral snakes helps protect the kingsnake
from predators.
Prediction?If predators confuse the kingsnakes with coral
snakes, then predators should attack fewer ringed snakes than brown artificial snakes.
Experiment?Scientists place brown artificial snakes in forest
and see how many attack it gets from predators compared to ringed snake.
Scientific method gone wrong!
http://www.youtube.com/watch?v=zrzMhU_4m-g
Observation:Village thinks a woman is a witch.
Question:Is she a witch?!
Hypothesis:“If she weighs the same as a duck, then she’s
made of wood, therefor SHE’S A WITCH!”Test:“She’s a witch, burn her!”
2.3 Understanding Science
Are these figures real? What do you need to prove that they are real?
EvidenceEvidence- Consists of a collected body of data from
observations and experiments. Theory-A well-tested explanation that makes sense of a
great variety of scientific observations.
Hypothesis vs TheoryHypothesis- “Mimicking poisonous snakes is an
adaptation that protects nonpoisonous snakes from predators.”
Theory- “Adaptations such as mimicry evolve by natural selection.”
Only become theory with extensive supporting research!
ModelsModels- Are physical, mental, or mathematical
representations of how people understand of process an idea.
Ex. Drawings, graphs, 3 dimensional objects, computer program.
Blood Flow Model
Science, Technology, and Society
Technology- Apply scientific understanding for some specific
purpose.
Microscope?Observe microorganismsStem cell research?Prevent heritable disease