Biological Principles

Biology – Science of life Greek – “bios” = life “logos” = study of Biology Botany Zoology (study of plants) (study of animals)

How do you tell if something is living? All living things are made of cells. All living things are highly organized. All living things use energy. All living things are able to maintain homeostasis. All living things grow as a result of cell division. All living things reproduce.

Nine Life Activities found in all living organisms: Nutrition – getting food Digestion – chemical changing of food into a form which is usable Absorption – getting water, ions, and food from the environment Biosynthesis (assimilation) – using food to make new protoplasm Respiration – process by which food is oxidized to release energy Excretion – separation of waste products Secretion – manufacture of special chemicals (hormones and vitamins) which affect other cells Response – change due to stimuli; varies Reproduction- cells dividing to produce new cells

Metabolism – the sum total of all chemical reactions which build up and tear down complex molecules

Scientific Method Goal of Science – investigate and understand nature Science is an organized use of evidence to learn about the natural world Science starts with observations – information gathered using the senses (data)

2 Forms of gathering data Quantitative – uses numbers (counting and measuring) Qualitative – uses the senses Inferences – interpretation based on what you already know

Quantitative Vs. Qualitative (data) Describing the color of a sample Describing the smell of a particular sample Touching an object to determine if it is smooth or rough *Usually includes an adjective Using a ruler to measure how much a plant has grown Using a thermometer to obtain the temperature of a sample Estimating the population of polar bears in the Arctic *Always includes a number (and unit)

Variables Variable – what is being manipulated can only test one variable at a time Two types of variables in experiments: Independent Variable Dependent Variable

Independent vs. Dependent Variables The variable directly affected by the independent variable Placed on the Y-axis Ex. Growth rate, acceleration, weight change Independent The variable that can be controlled by the experimenter (“I change”) Placed on the X-axis Ex. Time, depth, temperature

Graphing

Scientific Method A logical, organized method of study – used to establish scientific principles The beginning of the scientific method begins with an observation

5 Steps to the Scientific Method State the problem Make an educated guess, hypothesis, about the answer based on what is known (if-then); testable Design and conduct a controlled experiment to test the hypothesis a. control group – under normal conditions; variable not changed b. experimental group- exposed to the variable 4. Analyze the data collected 5. State the conclusion After much testing, the hypothesis may become a scientific principle or a theory.

Experiment 1 A student wants to determine the effect of differing amounts of fertilizer on the growth of ivy. Ivy plants of the same length are planted in the same amount of soil in three identical containers. The containers have the following amounts of fertilizer: The containers are placed in front of the same window. The length of the ivy is measured every five days, the observations are recorded in a data table. Container 1 5 mL Container 2 10 mL Container 3 no fertilizer

Experiment 1 What is the inference? Identify the experimental group(s). Identify the control group. What is the quantitative measurement? What is the qualitative measurement? What is the independent variable? What is the dependent variable? Make a good hypothesis for this experiment.

Experiment 2 A scientist is testing the efficiency of various microwaves by measuring the temperature of water after being heated for one minute at high power. What is the inference? Is this a controlled experiment? What is the quantitative measurement? What is the independent variable? What is the dependent variable?

The Microscope Magnification – power to increase an object’s apparent size Resolution – power to show detail clearly Light microscope – uses light Specimen – the object being viewed – must be thin enough to let light through

Compound Light Microscope 2 Kinds of lenses 1. ocular (A.K.A. the eyepiece) – magnifies 10X 2. objective – nearest the specimen The degree of magnification is determined by the combined magnification of the lenses. X stands for times

How to find total magnification: Multiply the power of the objective lens by the power of the ocular lens The powers are usually sketched on the side of the lens

Total Magnification 4 10 40 10 10 100 40 10 400 Scan Low High Objective Power of Ocular Total Magnification Scan Low High 4 10 40 10 10 100 40 10 400

Evolution Study of how organisms adapt to their changing environment over time Many different theories Speciation – introduction of new species resulting from evolution Important unifying concept in biology

Microevolution versus Macroevolution Small-scale changes Often can be observed in a lifetime in populations Does not result in speciation Macroevolution Large-scale changes Often debated Takes so long, often cannot be observed, so fossil data is used Results in speciation