WHAT IS BIOLOGY Living Environment Biology is the

WHAT IS BIOLOGY? (Living Environment) Biology is the name of the science that studies living things and their relationship to their environment.

Branches of Biology • Anatomy studies the structure of living things • Bacteriology studies bacteria • Botany studies plants

Branches of Biology • Ecology studies interactions of organisms with the environment • Embryology studies development of embryos • Genetics is the study of heredity

General Rules of Lab Safety

Metric Prefixes Symbol M k h da d c m u n Prefix Mega Kilo hecto deca deci centi milli micro nano Size 1, 000 10 1/1000 1/1, 000, 000

• What types of measurements do scientists use? • The Metric System M e a s u r e m e n ts

• Mass is the amount of matter in an object and is measured on a balance in grams. Mass is different than weight. Weight is caused by the force of gravity.

Measuring Mass • First place the object on the balance. • Then move the masses until they are equal. • Make sure the marks line up.

Measuring Mass • What is the mass of the rock? Round to the nearest tenth. • 134. 7 grams

Measuring Volume

• Volume is the amount of space an object takes up and is measured in one of two ways 1. length x width x height using a ruler 2. The displacement method which is used for irregularly shaped objects using a graduated cylinder and reading the amount of water that is “moved” by the object.

• Temperature is a measure of the amount of heat an object holds and is measured in degrees Celsius using a thermometer.

• Length is a measure of distance from one point to another and is measured with a ruler in meters.

Regents Question What is the approximate length of the earthworm shown in the diagram below? (1) 9 mm (2) 90 mm (3) 10. 6 cm (4) 106 cm

Regents Answer (2) 90 mm

Metric Measurements Measurement Units Equipment Length Meters (m) Meter stick Volume Liters (l) Mass Grams (g) Graduated cylinder Balance Temperature Celcius (C) Kelvin (K) Seconds (sec) Minutes (min) Time Thermometer Stop watch

Calculating Density • Use the formula Density = mass volume • Density of the rock mass = 134. 7 g volume = 55 ml • Density = 2. 4 g/ml

Float or Sink, what controls it? • Density • Any object that is denser than its surroundings will sink. • Any object that is less dense compared to its surroundings will float.

Phases of Matter and Density • Three phases of matter from most to least dense. – SOLID, LIQUID, GAS – Why is the order? • The cells get closer together as it goes from gas to solid, decreasing the volume for the same mass of materials • Is this the same for water? – NO • Most to least dense for water. – LIQUID, SOLID, GAS • Ice floats!

The Scientific Method

Scientists use the SCIENTIFIC METHOD to solve problems. The steps are: 1. Identify a problem or question 2. Research the problem 3. Form a hypothesis 4. Develop a Controlled Experiment 5. Record observations and data 6. Analyze data 7. Form a Conclusion 8. Retest

The hypothesis should answer your question • Examples: – Question: Do boys prefer girls who wear pink? – Hypothesis? Boys do not prefer girls who wear pink. -Question: Do lizards stand still when they are chased or do they run away? – Hypothesis? Lizards run away when they are chased

Regents Question A student placed five geranium plants of equal size in five environmental chambers. Growing conditions were the same for each plant except that each chamber was illuminated by a different color of light of the same intensity. At the end of 20 days, plant growth was measured. State a possible hypothesis for this experiment.

Regents Answer The color of light the geranium is exposed to will affect the growth of the plant.

Develop A Controlled Experiment • After the problem has been identified, research completed and hypothesis made, it is time to design the experiment. First, determine the dependent variable. The dependent variable is what you will measure or observe. ***DON’T FORGET YOUR UNITS!!!

• Next, identify the independent variable. • The independent variable is the one that you are manipulating (NOT OBSERVING). – EXAMPLES: time in minutes years percentage

5. 2. 1. What How In the observations about upper ingraph, thebottom can what you make based on 4. 3. How about in the this graph? is the data? dependent independent variable? graph?

• Finally, the experiment needs a control. – A control is a “normal” scenario from which to make a comparison • It is also important to study as large of a sample as possible to increase the validity of the experiment

Setting Up A Controlled Experiment (2: 00)

5. Record Observations and Data • The more trials conducted, the more likely you are to realize any mistakes in data collection and the more precise your data!

6. Analysis of Data • Examine the data and analyze it making a determination as to what it is saying. • Check to see if your data is complete or if more tests need to be conducted.

7. Form a Conclusion • Compare your analyzed data to your hypothesis. Was it supported or refuted (rejected/incorrect) • If it was refuted, you need to reexamine your data and find out why. • Include if any error was possible and what it was (ex. Impurities in chemicals, not collecting data in perfect time increments, triple beam balance was not perfectly balanced, etc. )

Regents Question Which statement best describes a controlled experiment? (1) It eliminates the need for dependent variables. (2) It shows the effect of a dependent variable on an independent variable. (3) It avoids the use of variables. (4) It tests the effect of a single independent variable.

Regents Answer (4) It tests the effect of a single independent variable.

Regents Question An experiment was carried out to determine how competition for living space affects plant height. Different numbers of plants were grown in three pots, A, B, and C. All three pots were the same size. The data collected are shown in the table below. Analyze the experiment that produced the data shown in the table. In your answer be sure to: • state a hypothesis for the experiment [1] • identify one factor, other than pot size, that should have been kept the same in each experimental group [1] • identify the dependent variable [1] • state whether the data supports or fails to support your hypothesis and justify your answer [1]

Regents Answer Allow 1 credit for stating a hypothesis. Acceptable responses include, but are not limited to: — Competition decreases plant height. — Competition increases plant height. — Competition has no effect on plant height. Note: Do not accept a hypothesis written in the form of a question. • Allow 1 credit for identifying one factor, other than pot size, that should have been kept the same in each experimental group. Acceptable responses include, but are not limited to: — same potting soil (type or amount) — environmental conditions (sunlight, H 2 O) — type of plant • Allow 1 credit for identifying the dependent variable. Acceptable responses include, but are not limited to: — height — size • Allow 1 credit for stating whether the information in the data table supports or fails to support the student’s hypothesis with appropriate justification. Acceptable responses include, but are not limited to: — The data supports my hypothesis because the plants in the pot with the greatest number of plants were the shortest. — The data does not support my hypothesis because the plants in pot C (20 plants) were shorter than the plants in pot A (5 plants). — The data did not support my hypothesis because the number of plants in the pot did affect the heights of the plant

A Controlled Experiment to test the effects of vitamin C on growth of impatiens bilflora CONTROL GROUP • 25 impatiens biflora • 6 inch clay pots • 4 inches potting soil • 25 m. L water daily at 12 noon • Greenhouse location EXPERIMENTAL GROUP • 25 impatiens biflora • 6 inch clay pots • 4 inches potting soil • 25 m. L water with 2 grams vitamin C solution daily at 12 noon • Greenhouse location

Regents Question Students were asked to determine if they could squeeze a clothespin more times in a minute after resting than after exercising. An experiment that accurately tests this question should include all of the following except (1) a hypothesis on which to base the design of the experiment (2) a large number of students (3) two sets of clothespins, one that is easy to open and one that is more difficult to open (4) a control group and an experimental group with equal numbers of students of approximately the same age

Regents Answer (3) two sets of clothespins, one that is easy to open and one that is more difficult to open

Regents Question Information concerning the diet of crocodiles of different sizes is contained in the table below. Which statement is not a valid conclusion based on the data? (1) Overharvesting of fish could have a negative impact on group C. (2) The smaller the crocodile is, the larger the prey. (3) Group B has no preference between reptiles and birds. (4) Spraying insecticides would have the most direct impact on group A.

Regents Answer (2) The smaller the crocodile is, the larger the prey.

Regents Question Substance X has a unique characteristic in that it fluoresces when exposed to ultraviolet light. An investigator added substance X to a dish containing a culture of cells. The investigator exposed the cells to ultraviolet light and found that substance X was highly concentrated only within mitochondria (cell organelles). Which assumption could the investigator make regarding the results of this experiment? (1) substance X could be used to identify mitochondria in living cells (2) substance X could be used to stain nuclei of living cells (3) all fluorescent substances will be absorbed by the mitochondria (4) all mitochondria synthesize fluorescent substances

Regents Answer (1) substance X could be used to identify mitochondria in living cells

• Allow 1 credit for stating the hypothesis to be tested. Acceptable responses include, but are not limited to: — Lice exposed to high temperatures will have a lower survival rate than those exposed to 98. 6°F (body temperature). — Lice not blasted with high temperatures will have a higher survival rate. – Note: Do not allow credit for a hypothesis written in the form of a question. • Allow 1 credit for stating one way the control group will be treated differently from the experimental group. Acceptable responses include, but are not limited to: — The control group will not be exposed to heat and the experimental group will be exposed to 140 -degree air. Note: Allow credit for an answer that is consistent with the student’s hypothesis for question 57. • Allow 1 credit for stating one result of the experiment that would support the hypothesis. — The lice blasted with the 140 -degree air had a lower survival rate than the lice not blasted with hot air. — The lice not blasted with high-temperature air lived longer. Note: Allow credit for a response that is consistent with the student’s hypothesis.