1.1 The Scientific Method A question or observation Research to create a hypothesis (testable!) Experiment/Data collection Analyze data and hypothesis Use tables and graphs! Report conclusion for peer review Peer review = process where experimental procedures and the results are evaluated by others Be safe and ethical in the process!

Overview

What is an observation? What is an inference? Being aware of something using your five senses Describe something as it appears: a fact What is an inference? A decision based on observations, which cannot itself be directly observed Ex. if you observe dark clouds in the sky, humid air, and puddles on the ground, you might infer that it has recently rained.

Observation Types Qualitative vs. Quantitative Some things can’t be observed using your senses (i.e.: radiation and cells) Solution? Technology (like Microscopes!)

Observation vs Inference List 3 Observations List 3 Inferences

Observation vs Inference List 3 Observations Brown stacked objects Multi-colored rabbit 2 ears, etc. List 3 Inferences Rabbits has been trained Items stacked are cookies Rabbit is on a bed

1.2 Experimental Design Control: comparative group Experimental group: tested group Independent variable: altered factor Dependent variable: measured factor Constant: unchanged factor(s)

Step 3: Form a Hypothesis Write the hypothesis in an If-Then statement ex: If the amount of fertilizer is increased, then the height of the plant will increase. The “if” is the IV The “then” is the DV

Data Types Data can be numeric = quantitative Data can be descriptive = qualitative Scientists type to be quantitative to remove bias Ex. bubbles created are large or small (qualitative) vs. measure bubble size in centimeters (quantitative)

Types of variables: Independent – ONE variable altered by scientist ex. Coffee drank/day: 1 cup, 2 cups or 3 cups Dependent – effect measured by scientist ex. Amount of sleep at night in hours after drinking the coffee Constants (controlled) – all other variables should be kept the same so any DV changes are due to the IV

Independent Variable Dependent Variable Also Known As: Manipulated Variable Responding Variable Results: Cause Effect On a graph: X axis Y axis Experimenter Changes or controls Measures

Now You Try: If you spend more time studying, then your grade will improve. Independent Variable = Dependent Variable = If the temperature of the room is increased, then the bacteria will grow faster.

Control Groups Represent a group left unchanged for comparison I have a drug that makes you live 4 years on average from a heart attack What do you need to know before you take that drug? How long do people not given the drug live on average after a heart attack No drug = group left unchanged Could be a plant in normal sunlight, people not on a diet, etc. A Control group provides a critical comparison

Analyze and represent data

Organize your data Store observations in a data table Independent Variable __________(unit) Levels Dependent Variable _______________ (unit) Trial 1 Trail 2 Trail 3 mean range

Organize your data Make the data table into a graph GRAPHS make it EASIER to see patterns in the data!

Step 6: Organize your data DRY MIX Dependent Variable = Responding Variable = Y axis Manipulated Variable = Independent Variable = X axis

Y Axis (Dependent Variable) X Axis (Independent Variable) Parts of a graph Y Axis (Dependent Variable) X Axis (Independent Variable)

Graphing: DRY MIX Dependent Variable Independent Variable

1.3 What is Science? Objective way of viewing/interacting with the world Self-correcting and collaborative (peer review) Questioning (known, unknown, each other) Looking for, and trying to solve problems

Scientific Theory Explains natural phenomenon Supported by many observations/experiments Not a hypothesis Can be modified or discarded by NEW info Ex. Gravity, cells Note: Scientific Law is observation (things always fall) not an explanation

Example Scientific Theories Evolution – Groups change over time due to environmental selective pressures. Cell – Cells are the basic unit of life, structure, and organization. Cells come from other cells. Germ –Microbes like bacteria, viruses, and fungus travel between organisms and cause disease

1.4 Biology Study LIFE Solve biological problems Interactions, structures, functions … Solve biological problems Agriculture, disease, conservation …

So what is life? We decide Scientific consensus rules

Life Traits I 1+ cells Complex Chemistry Grow/develop The cell is the basic unit of life Complex Chemistry Organized (molecules->cells->etc), Uses energy, Genetics Grow/develop Increase cell size and/or increase cell number

Life Traits II Respond to the environment Reproduce Homeostasis Able to process and react to internal/external stimuli Reproduce Species = group of organisms that can interbreed to get fertile offspring, allows for evolution Homeostasis Regulate internal conditions Ex: too hot = ?

1.5 Principles of Biology Cell Theory Gene Theory Cells are the basic unit of life (simple and complex) Gene Theory DNA in cells carries info that determines your traits and can be passed on to your offspring

Principles of Biology 3-4 Homeostasis Life must maintain balance/stability, and has mechanisms to help it do so (within reason). Evolution Natural selection means individuals with beneficial genes live/reproduce more, making those genes/traits more common over time.

What not to do in Biology Assume organisms are identical or perfect Assume what works now works always Assume you or anyone else knows everything Assume nature is friendly, noble, peaceful, or fair