Biology: The Study of Life

Biology: The Study of Life

I. Science means ‘to know’ (in Latin) A. Science is: • A body of knowledge • A process to learn about the world B. Biology is: • Study of Life • Biologists study the diversity of Life

I. Characteristics of Living Things: 1. Living things are made up of cells 2. Living things reproduce (not essential for survival but essential for continuation of species (a group of organisms that can interbreed and produce fertile offspring in nature) 3. Living things change: growth and development 4. Living things adjust to their surroundings (stimulus/response interactions) 5. Maintain homeostasis (balance internal condition) 6. Living things adapt and evolve 7. All Living things must Obtain and use energy 8. Have DNA Living Organisms – possess all of the characteristics of life

So, What Is The difference:

Homeo…. What??? • Homeostasis: Process by which organisms maintain constant and stable internal conditions. IE: In order to survive, there are several conditions that your body must remain stable. Like body temperature, salt and sugar levels, etc. Your body works like the furnace in your home.

The Scientific Method: a method of investigation involving observation and theory to test scientific hypotheses • Hypothesis: An educated guess based upon an observation. • Prediction: A prediction is a statement or claim that a particular event will occur in the future. Usually written as an If /Then statement. • Observation: Using your senses to gather data. • Inference: The process of making decisions about what the data means.

Observation Vs.Inference Activity • Your teacher, Mrs. Wade, will be absent for the rest of the term. She won the lottery and thus decided to take a cruise around the world with her friends, Ms. Towns and Mrs. Fernandez. She has left each team a box containing 3 personal items. She would like you to make 2 observations and two inferences about each item (you have 5 minutes for this activity). • Non-related example: You observed that the ground was wet. Therefore, you infer that it had just rained.

Types of Observations:

Applying The Scientific Method make observations / state problem form hypothesis design controlled experiment use a control change 1 variable collect data analyze results may not support hypothesis may support hypothesis draw conclusion / publish form a new hypothesis

B. Parts of a Controlled Experiment 1. Types of Variables • Independent variable (aka Manipulated variable): • a factor that is manipulated to see what the result will be • Dependent variable (aka Responding variable): • a factor that responds to the changes in the independent variable

Dependent Vs. Independent Variables

Parts of a Controlled Experiment 3. Experimental groups: • the groups where all conditions are held constant EXCEPT the one being tested 4. Controlled variables: Variables that the experimenters keep the same throughout the experiment. that are held constant at all times.

An Example Experiment Mrs. Fernandez’s son, Dominick, would like to know what will happen to his gummy bears if he places them in water. So, he obtains three (3) gummy bears (all are of the same brand). He places one in 20 mls of water for 3hrs, the other for 12 hrs, and the last for 24 hrs. He uses a 25ml graduated cylinder each bear. 3 mL 6 mL 0 mL

Your Turn…. • What is the independent variable in Dominick’s experiment? In what axis do graph it? • What is the dependent variable in the experiment? In what axis do you graph it? • What are the controlled variables in the experiment?

C. Drawing a Conclusion The conclusion should always have two main parts. • Confirm or reject the hypothesis • Was the hypothesis correct? • Overall statement of what was learned • What happened and why did it happen? • What’s the main idea?

D. Publishing Results • When a hypothesis has been tested and supported many times, a theory is formulated and published. • A theory is the best explanation science has to offer about a problem.

III. Other things to keep in mind: A. Always use metric system! • Distance: meters • Volume: liters • Temperature: oC • Mass: grams How big are these four ticks?

Metric Prefixes Kilo - 1000 units k Hecto - 100 units h To convert to a smaller unit, move decimal point to the right or multiply. Deka - 10 units da Basic Unit Deci - 0.1 units d Centi - 0.01 units c Milli - 0.001 units m To convert to a larger unit, move decimal point to the left or divide. Micro- 0.000001 Units m Nano - 0.000000001 units n *Metric Mania Worksheet Practice

Kinds of DATA 1. Quantitative: produces numerical data that can be comparatively analyzed in graphs and tables a. Tables: Title Table, Columns & Rows have titles b. Graphs: -3 main types: line Graphs (measures change/ time), bar (used for comparing), & circle (shows %) 2. Qualitative: Descriptive data; written descriptions of observations

Gummy Bear Lab Read lab directions in lab hand-out and on board • Conduct the lab. • Clean up (everything must be spotless when lab is completed). • Graph and answer questions • Turn in assignment.

Let's Review

OBSERVATIONS: Flies land on meat that is left uncovered. Later, maggots appear on the meat. HYPOTHESIS: Flies produce maggots. PROCEDURE Uncovered jars Covered jars Controlled Variables: jars, type of meat, location, temperature, time Several days pass Manipulated Variables: gauze covering that keeps flies away from meat Responding Variable: whether maggots appear Maggots appear No maggots appear CONCLUSION: Maggots form only when flies come in contact with meat. Spontaneous generation of maggots did not occur. Redi’s Experiment onSpontaneous Generation

Identifying Variables • Two groups of students were tested to compare their speed working math problems. Each student was given the same problems. One group used calculators and the other group computed without calculators. • What is the independent/manipulated variable? • What is the dependent/responding variable? • What is the controlled variable?

Identifying Variables • Students of different ages were given the same puzzle to assemble. The puzzle assembly time was measured. • What is the independent/manipulated variable? • What is the dependent/responding variable? • What is the controlled variable?

Identifying Variables • A study was done to find if different tire treads affect the braking distance of a car. • What is the independent variable? • What is the dependent variable? • What is the controlled variable?

Identifying Variables • An experiment was performed to determine how the amount of coffee grounds could affect the taste of coffee. The same kind of coffee, the same percolator, the same amount and type of water, the same perking time, and the same electrical source were used. • What is the manipulated variable? • What is the responding variable? • What are the controlled variables?

Identifying Variables • A study was done with an electromagnet system made from a battery and wire wrapped around a nail. Different sizes of nails were used and the number of paper clips that the electromagnet could pick up was measured. • What is the manipulated variable? • What is the responding variable? • What are the controlled variables?

Identifying Variables • A study was attempted to find if the length of the string in a string telephone affected its sound clarity. • What is the independent variable? • What is the dependent variable? • What are the controlled variables?

But That’s NOT All! A law is a statement of fact that describe, in an action or set of actions. It is generally accepted to be true and universal, and can sometimes be proven mathematically. For example, the law of gravity or Newton’s laws of motion. What is a scientific LAW? But then what is a 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; he can only create a hypothesis. For example, the theory of relativity or evolution.

But That’s NOT All ALL! • How is THEORY used in everyday speech that is scientifically incorrect? • Bryant might say that he has a theory that Mrs. Wade will yell at the class today… • What would be a more ACCURATE word to use? • If he had made the same statement but had replaced theory with hypothesis, THEN he would be scientifically correct!

Microscopes • What is a light/compound microscope? • http://www.southwestschools.org/juniorschool/jsfaculty/Microscopes/compoundscope.html

Microscopes Allows scientists to view a universe too small to be seen with a light microscope. They don’t use light waves; they use electrons (negatively charged electrical particles) to magnify objects up to two million times. What is an electron microscope? What is the difference between TEM (transmission electron microscope) and a SEM (scanning electron microscope)? -> click on cool linkhttp://school.discoveryeducation.com/lessonplans/interact/vemwindow.html TEMs allows beams of electrons to go through the specimen while SEMs beams of electrons bounce off of the specimen and result in a 3D image. All images are black and white…why?

Biology: The Study of Life