chapter 2 the science of biology

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