Intro to Biology Purpose: to introduce the recurring themes of this course and describe the mechanisms by which science is explored

Types of Science:

What is Science???  S tudy of a topic that seeks to understand and explain the universe around us. Often requires experimentation and must be supported by evidence

Pure vs. Applied Science:  Pure: learning new things about the world (basic research)  Applied: solving problems (technology; medicine)

You notice something - Pushing the button did not turn the flashlight on. (Observation) It makes you wonder, why? Or How? - What is wrong with the flashlight that it didn’t turn on? (Ask a Question/State your Problem) You think about it for a while and then propose a possible explanation. – The batteries are dead (Form a Hypothesis) You decide to test out your idea – Replace the batteries in the flashlight, and push the button again (Experiment) Does it look like your hypothesis was right? Support of Hypothesis After many repetitions of the tests by you and other “observers”, all of which continue to support your hypothesis…. Hypothesis becomes a Theory You look at the results of your tests – did the flashlight turn on? (Data analysis) Or do your results suggest something else? Scientific Method New Hypothesis You can make a testable prediction that will be true – If I replace the batteries, the flashlight will work. (Make a prediction)

Types of experiments:  Controlled Experiments: We manipulate 1 variable while keeping others the same; Measure the effect of changing that one variable  Comparative/Field Studies: We don’t manipulate any variables Look at groups that are inherently different and measure effect of those differences

 Types of Variables: Dependent: variable that is measured; results or outcome of experiment; data collected; Remember: D is for DATA!! Independent/Experimental: variable that the scientist manipulates; Believed to have an effect on dependent variable

Easy to identify variables  Take every experiment and phrase it as follows:  We are testing the effect of _________ on _____________. The first blank is the independent variable and the second is the dependent.

What else does an experiment need?  Control/control group: test subjects that are not manipulated; used for comparison; same in every other way  Experimental group: test subjects that are receiving different treatments of the independent variable;

What else does an experiment need?  Constants: characteristics that ALL test subjects have in common; Do not change

Others we’ve already talked about:  Test subjects, Sample size, Measuring tools and units, margin of error.  See your lab for more info on these.

Examples: Group 1 Group 2 Group 3 Find 3 environments know to have different levels of herbicide Gather frogs from each environment Measure differences in three groups Of frogs What kind of experiment? - controlled or comparative? - why?

Examples: 3 groups; same type of frog Dosage of herbicide 0 ppm1 ppm5 ppm Record changes in reproductive systems What kind of experiment? - controlled or comparative? - why?

Pros and Cons of two types of experiments

What is the difference between your data and your conclusion?? Data are your recorded Observations A conclusion should be what those results suggest about the initial hypothesis.

Back to our frogs What might our data look like? What might our conclusion look like?

How is a theory different from a hypothesis?  MISCONCEPTION: If evidence supports a hypothesis, it is upgraded to a theory. If the theory then garners even more support, it may be upgraded to a law.  In other words: Theories don’t graduate into laws and laws don’t get “down graded” into theories.

Examples of theories  The theory of evolution  The theory of relativity  The atomic theory  The quantum theory  A theory is an explanation of a set of related observations or events based upon proven hypotheses and verified multiple times by detached groups of researchers. One scientist cannot create a theory; she can only create a hypothesis.

 A theory is the most well supported and agreed upon explanation for a phenomenon based on CURRENT evidence. Can a theory change?? When does a theory change?

Okay…it is NOW TIME FOR….

The study of living things how they work how they interact with the environment how they change over time Included in this is are many specific areas of study such as medicine, nutrition, genetics, physiology, microbiology, ecology, environmental studies, evolution and biochemistry (just to name a few).

Living vs. Non-living  Two main components of the environment. Abiotic-  Examples? Biotic –  Examples?

ENERGY IS A BIG DEAL  Living things must obtain nutrients and energy  Why do we need to do this?  The “stuff” we eat/use for energy moves us into the abiotic world and a little chemistry

Chemistry explains what life is made of!  We are made of matter - anything that has mass (takes up space no matter how small).  We use Energy to do work – Energy isn’t matter, however we can get it from matter  All the matter is made up of tiny particles called atoms

WHAT REALLY MATTERS FOR LIFE???  Only a few types of atoms (called elements) are used to make up most of a living thing C-H-O-N-P-S are the major ones!  These atoms are not yours alone! They have been shared with the environment and other living things! (and actually…came from stars!

Elements in Earth’s crust vs. humans Earth’s crustHuman Body ELEMENT % composition ELEMENT % composition Oxygen46Oxygen65 Silicon27.7Carbon18 Aluminum8.1Hydrogen10 Iron5.0Nitrogen3 Calcium3.6Calcium1.5 Sodium2.8Phosphorus1.0 Potassium2.6Potassium0.35 Magnesium2.1Sulfur0.25 All others1.5Sodium0.15 Plus Trace Elements

The atmosphere 79% nitrogen 20% oxygen 1% other gases. Argon, (Ar), Carbon dioxide (CO2), Methane (CH4) and others

How do we share? These major atoms are recycled constantly

So certain elements can cycle between abiotic and biotic factors!

Other important Abiotic factors  Water: essential to life and is recycled

Other important Abiotic factors  Soil: primarily made of decomposed living things mixed with small, to very small rock particles  Earth(rock): geology, but essential to formation and structure of our planet Even rocks cycle. How??

In other words, the same types of atoms can be combined differently to make both living and non-living things!

What is life?  There is a lot of Diversity in life, what do they all have in common??

Requirements to be alive!  Must be made of one or more cell  Must Reproduce Where are the “directions”?  Grow and develop

Requirements to be alive!  Must respond to stimuli (changes in environment)  Maintain homeostasis(through responses to environment) Examples:

Requirements to be alive!!  Must metabolize: Take in/produce food and perform chemical reactions to transform the energy in food into a useable form called ATP Metabolism: sum of all chemical processes (in living things)

Requirements to be alive!  Must evolve (change) over time Refers to species, not an individual

Are there exceptions?  Consider these: Viruses: not made of cells, but can infect cells and use their machinery to reproduce

Are there exceptions?  Consider these: Mules: made of cells, but can not reproduce

Are there exceptions?  Consider these: Fire: not made of cells, but metabolizes, grows, reproduces?

Themes for the year…

Themes to look for ALL year!!!  Energy: needed for everything. Where does it come from? Where does it go? How is it transformed?

Themes to look for ALL year!!!  Form fits function: how does something’s structure help it do its job?  Adaptation: what advantage does a certain trait provide?

Themes to look for ALL year!!!  Genetic Programming: how do our tiny little cells “know” how to do all this? Why do humans always make more humans?