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

Types of Science:  Examples?

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: science to uncover new information about the world (basic research)  Applied: using information to make discoveries to improve living conditions (technology; medicine)

You notice something (Observation) It makes you wonder, why? Or How? (Ask a Question/State your Problem) You think about it for a while. Based on the knowledge you have, you think you have an idea, but aren’t sure (Form a Hypothesis) You decide to test out your idea (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. (Data analysis) Or do your results suggest something else? Scientific Method New Hypothesis

Types of Data Quantitative  This type of data is ALWAYS numeric and is usually some type of measurement. Qualitative  This type of data is often in “words” or sometimes “rankings”

What do experiments need?  Types of Variables: Dependent: what you measure; data you collect; your results (D is for DATA!!) Independent/experimental: the specific factor you are testing; will be different in each set up and missing in the control

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: test subject that doesn’t receive experimental treatment; used for comparison;  Constants: characteristics of the experiment that remain the same between test subjects

Key Terms:  Sample Size: number of subjects that you run your experiment on  Sampling Error: error that arises from testing too few subjects

Key Terms  Accuracy Your average measurement is the same or very close to the “real” measurement. Your individual measurements can be quite different from each other.  Precision Your individual measurements are the same or very close to each other but may be very different from the “real” measurement.

 Example experiment: You want to determine what the optimal amount of water is for plants. You set up 4 identical corn plants and give them each different amounts of water over two weeks.  Plant 1: no water  Plant 2: ½ liter  Plant 3: 1 liter  Plant 4: 1.5 liter  Collect data, draw a conclusion

 Which plant is the control?  What is the sample size?  What is the dependent variable?  What is the independent or experimental variable?  What are some constants?  Why is the control important?

What is the difference between your data and your conclusion?? Observation vs. interpretation Data: the plant that got the most water grew the tallest Conclusion: Water helps plants grow tall.

How is a theory different?

 A theory is the most rational explanation for a phenomenon based on CURRENT data and evidence. Agreed upon by majority Can a theory change??

What about two independent variables You have looked at several gardens in the area and notice that the same type of flowering plant (zinnia) has many more blossoms in some gardens than in others.  Gardens that are are shaded less than 2 hours a day seem to have more flowers than those that have more than 2 hours of shade.  Additionally watering every other day also seems to produce the most blossoms when there is less than two hours of shade.  How would you set up an experiment to determine the effects of sun and water?

Results GardenshadewaterBlossoms / plant 1< 22X/WEEK11 2> 448 hours7 3>42X/week5 4>42x/week4 5<248 HOURS13 6<248 HOURS15 7<22x/week12 8>448 hours6 9<22x/week11 10>42X/week5 11<248 hours10 12>448 hours8

Biology: 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?

DO NOW QUESTIONS: Handout: The Birth of Earth  What are the first two elements of the universe?  How did we get more elements?  What are planetesimals and how did they form?  What created layering of the planetesimals and thus….gave us our planets  The oldest surviving earth rocks did not form until 600 million years after earth was formed…Why?

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 CHONPS are the major ones!  These atoms are not yours alone! They have been shared with the environment and other living things!

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. The other gases include Argon, (Ar), carbon dioxide (CO2), methane (CH4) as well as many 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  Earth/rock: fits into 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) to maintain homeostasis 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

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 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?