Science as Process. What goes into Good Science?

Science as Process

Basic Biological Principles(Bio.A.1)

What goes into Good Science?

Experimental DesignStart with a question.Do background research.Develop your hypothesis.Determine what the variables are and how you will

measure them quantitatively (with numbers). Identify your control (if applicable).Write your procedure.Prepare data tables.Collect data (perform experimentation).Graph data.Analyze and discuss data. Was your hypothesis true?

VariablesVariable – values in an experiment that can change

Control – group in an experiment where all variables are kept the same with no changes; typically this is the “normal” conditionControls are used so that you can compare normal and experimental groups

Independent variable – the variable that scientists purposefully change; the variable that is being “tested” or “questioned”

Dependent variable – the responding variable; the variable that changes as a result of the independent variableThe changes in the dependent variable

are caused by the independent variable.

Example

Question: Which color of light makes plants grow the highest in length: red, green, or white?

What is the independent variable? What is the dependent variable?

Use the following sentence to figure out the variables.

The ____________ changes the _____________.

Independentvariable

Dependentvariable

Qualities of Good experiments…

They…..have multiple trials (typically requires

finding averages).have quantitative data (numerical).test only one independent variable and

one dependent variable.should be able to be repeated by other

scientists.

Rules For GraphsIndependent variable goes in the X-axis. (remember Index)

Dependent variable goes in the Y-axis.Label both axes and include units.Give the graph a descriptive title.Use a key or legend if needed.Scale must include all data points.The scale on an axis must have equal

intervals.

Rules For TablesLabel the columns and rows. Include units.Give the table a descriptive title.

Scientific Terms

Hypothesis - a proposed, scientifically testable explanation for an observed event.Example: Red light will make plants grow 50%

taller than green light and 25% taller than white light.

Inference - a conclusion based on observations, knowledge, and scientifically tested hypothesesExample: After collecting data it was found that

white light caused plants to grow taller than red or green lights.

Law or principle- an explanation of scientific events that can be explained using mathematics and is observed to be the same throughout the universeExample: First Law of Thermodynamics -

energy cannot be created nor destroyed…Example: Principle of segregation – describes

how genes separate in forming sperm and eggsTheory - a widely tested and accepted

explanation of science ideas based on observation, measurement, and logicExample: Cell theory – all life is made up of

cells…

Cells and the Organization of Life

Basic Biological Principles(Bio.A.1)

All living things:1. Are made of one or more

cells2. Reproduce3. Are based on a universal

genetic code4. Grow and develop

Characteristics of Living Things

5. Take in materials and energy and get rid of waste

6. Respond to their environment

7. Maintain a constant internal environment.

8. Change over time (evolve).

Characteristics of Living Things

Cell Theory1. All living things are made

up of cells.2. Cells are the basic units of

both structure and function in living things.

3. New cells are made only from existing cells.

LIFE IS CELLULAR

All cells have:Plasma membrane (cell membrane) – thin layer that surrounds cells

Cytoplasm – gel like material inside cells (the “juice”)

Genetic material (DNA and/or RNA)

Ribosome – organelle where proteins are made

BASIC CELL STRUCTURE

Some cells have:Cell wall – a more rigid structure on the outside of some plasma membranes

Nucleus – a membrane-bound organelle that contains genetic material (brain of the cell)

Mitochondria – a membrane-bound organelle where energy is released (respiration)

Chloroplasts – a membrane-bound organelle (a type of plastid) where glucose is made (photosythesis)

Rough endoplasmic reticulum – a membrane-bound organelle that transports proteins

Golgi apparatus – a membrane-bound organelle that packages and processes proteins

Vacuole – a membrane-bound organelle that stores water and nutrients

All cells fall into two categories of cells:1. Prokaryotes

Includes bacteria and Archaea2. Eukaryotes

Includes animals, plants, fungi, and protists (like amoebas and paramecium)

DIVERSITY OF LIFE

All Cells

Prokaryotes

Archaea

Bacteria

Eukaryotes

Protists Fungi Animals Plants

Very basic structureUnicellularNo membrane-bound organelles (“little

organs” in cells)No nucleus, mitochondria, or chloroplastsDo Have DNA, ribosomes, cytoplasm,

plasma membrane, and cell wallFirst living things on the planet. Fossil

evidence shows that bacteria have been on the earth for over 3.5 billion years

CHARACTERISTIC OF PROKARYOTES

Prokaryote

Microbial Family Tree

Plasma membraneCytoplasmCytoskeletonRibosomesOrganelles that are membrane bound (ex.

mitochondria and chloroplasts)Fossil evidence shows that eukaryotic cells

have been on the earth for approximately 1 billion years.

Can be unicellular or multicellular

CHARACTERISTICS OF EUKARYOTES

Animal Cell

Plant Cell

Levels of Biological Organization

We need to look at ecosystem to biosphere more closely.

Levels of Biological Organization

Cell – basic unit of structure and function (ex. nerve)

Tissue – groups of cells that work together to perform a common function (ex. spinal cord or muscle cell)

Organ – groups of tissues that work together to perform a common function (ex. brain or heart)

Organ systems – groups of organs that work together to perform a common function (ex. cardiovascular or nervous system)

Body – groups of organ systems

LOBO—Some important definitions for this unit.

1.

2.

3.

4.

What LOBO would each of these fall into?