Chapter 1: The Science of Biology Pages 2-33

Chapter 1-1: What is Science? Pages 2-7

Vocabulary 1-1 observation data inference hypothesis theory

Question: Why do we study science? Three Main Goals of Science: 1. To investigate and understand nature 2. To explain events in nature 3. To use explanations to make useful predictions

Science starts with observation – using our senses to gather information! Info gathered is called data Two types of observations: 1)Quantitative: involves #’s (ex. counting, measuring) 2)Qualitative: involves things that cannot be counted (ex. color, texture)

What are some quantitative observations from this photo? What about qualitative?

Processing the Data Observations are interpreted – called inferences (a logical interpretation based on prior knowledge or experience) Inferences lead to a hypothesis (a possible explanation for a set of observations or an answer to a problem) Hypotheses must be testable! They are only supported or refuted, NEVER PROVEN!

Processing the Data When numerous tests and evidence support a hypothesis, it becomes a theory (a well-tested explanation that unifies many observations)

What makes a good scientist? Curiosity Honesty Openness Skepticism Recognition that science has limits Remember…achieving the goals of science does not depend on science alone – very often our society, laws, morals all play a part in making final decisions regarding science.

Chapter 1-2: How Scientists Work Pages 8-15 Chapter 1-4: Tools and Procedures Pages 24-28

Vocabulary 1-2 and 1-4 scientific method control variable electron microscope metric system microscope light microscope

Question: What steps do scientists take to solve problems? Answer: They use the Scientific Method. Definition: an organized way to solve a scientific problem

Scientific Method 1) Stating the problem Use observations to define a problem 2) Forming an hypothesis Use prior knowledge and experience to make a prediction

3) Setting up a controlled experiment Test your hypothesis with a controlled experiment In a controlled experiment, only one variable in the experiment is tested at a time – all other variables must be kept the same (or controlled) control: factor that is not changed variable: factor in an experiment that can change

A little more on variables… independent variable – the variable that is deliberately changed (point of comparison) dependent variable – changes in response to the independent variable (support or refute hypothesis) ***All other variables must be controlled, or kept constant.***

4) Recording and analyzing results Keep accurate records of all data Data is only useful after it is analyzed 5) Drawing a conclusion Review hypothesis and draw a conclusion – either the hypothesis was supported or refuted An hypothesis is never proven…only supported or refuted!!

Example: Controlled Experiment – Growth of Bread Mold Let’s go through the scientific method to create a controlled experiment…

Famous series of experiments using the Scientific Method: Redi (1600’s) – Spontaneous Generation

Question: How do scientists collect data? Scientific measurements must always have a NUMBER and a UNIT Metric system: a decimal system based on certain standards and scaled on multiples of 10 Also known as the International System of Units, or SI Base unit tells the type of measurement Prefix indicates the size of each unit in relation to base unit

Common Prefixes kilo - (k) x hecto - (h) - 100x deka (da) or (dk) - 10x deci - (d) -.1x centi - (c) -.01x milli - (m) -.001x

Common Metric Units Length = Meter (m)Mass = Gram (g) 1 meter (m) = 100 centimeters (cm)1 gram (g) = 1000 milligrams (mg) 1 meter (m) = 1000 millimeters (mm)1 kilogram (kg) = 1000 grams (g) 1000 meters (m) = 1 kilometer (km)1000 kilograms (kg) = 1 metric ton (t) Volume = Liter (L)Temperature = Celsius (°C) 1 liter (L) = 1000 milliliters (mL)0°C = freezing point of water 1 liter (L) = 1000 cubic centimeters (cm 3 ) 100°C = boiling point of water

Common Measurements Length = distance from one point to another (meter)

Measurement Tools: Length Tools: Meter stick or ruler

Common Measurements Volume = the measure of the amount of space an object takes up (liter)

Measurement Tools: Volume Tools: Graduated Cylinder or Beaker

Using the Graduated Cylinder A graduated cylinder is a glass tube that is marked with divisions to show the amount of liquid in it. The surface of the liquid will have a “belly-down” curve called a meniscus.

Place the cylinder on a flat surface. Read the mark that lines up with the bottom of the curve. Using the Graduated Cylinder

Common Measurements Mass = a measure of the amount of matter in an object (gram)

Measurement Tools: Mass Tool: Balance

Organizing Data After collecting data from an experiment, it is important to present it in an organized manner, either with graphs or tables Graphs provide a visual representation of the collection of data or results of the experiment

Graphs Complete graphs contain: 1)A title 2)Labels for the X and Y axes X axis typically shows the constant (ex. time) Y axis typically shows the factor that is changing (ex. number of offspring) Both labels must contain units 3)Key

Microscopes Devices that produce images of structures that are too small to see with the unaided eye Two types important in biology: 1) Light microscope 2) Electron microscope

Light Microscope Most commonly used microscope Magnify objects up to about 1000 times Can be used to see tiny organisms and cells while still alive Special dyes can be used to show different structures

Electron Microscope Uses electrons as its source of illumination or vision Can form images of objects 1000 times smaller than those visible using a light microscope Two types: 1) Scanning (SEM) – electrons go across image and make 3-D image of surface 2) Transmission (TEM) – electrons go through object – must be thin Cannot be used to study live specimens (processes used would kill them)

SEM (very large, very expensive)

Mosquito Head (SEM Image) X 200 X 1,000

Cell Parts (TEM Image) endoplasmic reticulum/mitochondria/ribosomes

Chapter 1-3: Studying Life Pages 16-22

Vocabulary 1-3 biosphere tissue ecosystem community population homeostasis species evolution organism DNA cell biology sexual reproduction asexual reproduction metabolism

BIOLOGY IS THE STUDY OF LIFE. Living things have 8 common characteristics: 1)Made up of cells 2)Reproduce 3)Based on a universal genetic code 4)Grow and develop 5)Obtain and use materials and energy 6)Respond to their environment 7)Maintain a stable internal environment 8)Change over time

1) Made up of units called cells Cell: a collection of living matter enclosed by a barrier that separates the cell from its surroundings cells are the smallest unit of an organism that is considered alive some living things are composed of 1 cell (unicellular); others are composed of several cells (multicellular)

2) Reproduce Two kinds of reproduction: 1) Sexual - 2 cells from different parents unite to produce the first cell of the new organism 2) Asexual - a single parent reproduces by itself (ex. budding)

3) Based on a universal genetic code Genetic code of DNA determines the inherited traits of every living thing on Earth What does this mean? DNA is a molecule that contains the directions for inheritance

4) Grow and develop Each type of organism has a distinctive life cycle – they grow in size and number of cells The cells also differentiate for specialized tasks (ex. heart cells vs. brain cells)

5) Obtain and use materials and energy metabolism – combination of chemical changes in which an organism builds and breaks down materials as it carries out its life functions

6) Respond to their environment 7) Maintain an internal balance homeostasis – the process by which organisms keep their internal conditions relatively stable, despite changes to external environment; it is necessary for survival 8) Change over time as a group, or evolve a single individual does not evolve but a group of individuals can evolve or adapt over a long period of time

Living things can be studied on many levels…from very large to very small. Biosphere – sum total of all the ecosystems on Earth Ecosystem – communitiesand their non-living environment Community – populationsliving together in the same area Population – members of the same species living together in the same area

Levels of Organization Species – organisms that: 1)can mate 2) produce fertile offspring 3) in nature (the wild vs. the lab) Organism – individual living thing

Levels of Organization Tissue – group of cells working together to do a job Cell – smallest functional unit of life

Levels of Organization Biosphere Ecosystem Community Population The part of Earth that contains all ecosystems Community and its nonliving surroundings Populations that live together in a defined area Group of organisms of one type that live in the same area Biosphere Hawk, snake, bison, prairie dog, grass, stream, rocks, air Hawk, snake, bison, prairie dog, grass Bison herd

Levels of Organization Organism Groups of Cells Molecules Individual living thing Tissues, organs, and organ systems Smallest functional unit of life Groups of atoms; smallest unit of most chemical compounds Bison Nervous tissue Nervous system Brain Nerve cell Water DNA Go to Section:

Have you ever heard of “nesting dolls?”