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)

Scientific/Engineering Practices  Ask Questions and Define Problems  Develop and Use Models (eng)  Plan and Carry Out Investigations (sci)  Analyze and Interpret Data  Use Mathematical and Computational Thinking  Construct Explanations and Design Solutions (eng)  Engage in Argument from Evidence (sci)  Obtain, Evaluate and Communicate Info.

Science is Iterative  A good experiment usually generates more questions.  You may have to change your question  You may have to repeat the same experiment (confirmation)  You may have to ‘rethink’ your whole study.

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

Controlled Experiments  Pros Greater access to a wide variety of research tools and equipment More control over the experiment  Cons Space can be an issue Unnatural environment may change results

Field Studies  Pros Can observe things in their natural setting Best for behavioral studies  Con You have little/no control over conditions May have more than one variable changing at a time

In reality….  You often use elements of each.  You may start in the field,and end up in the lab, or vice-versa.  Both are important!

 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

What else do we need to consider:  Test subjects  Sample size  Measuring tools  Units of measure  Margin of error.  We will work on these in the lab activity!

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 for this experiment

What is the difference between your data and your conclusion?? Data Recorded Observations Conclusion What Observations (Results) suggest Conclusions are INFERENCES support by the data.

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

How is a theory different?

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

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?

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?