Science Of Life Unit 1

The Scientific Method

We use the Scientific Method, a series of investigative steps, to solve problems.

Step 1 Make Observations: –Noting objects or events by using the senses Ex: Noticing maggots on rotting meat.

How good are your observation skills? s/demos/23.htmlviscog.beckman.uiuc.edu/graf s/demos/23.html

Step 2 Form a Hypotheses: –Making an educated guess or explanation Ex: Suggesting maggots arise from meat. (that somehow the meat produces the maggots)

Step 3 Make Predictions: –Expecting something to happen based on hypothesis Ex: Any time meat is left to rot, maggots will appear on the meat.

Step 4 Perform Experiments: –Using controlled experiments to test hypothesis Ex: Place meat in various locations/situations, to see if maggots appear on all the meat.

Step 5 Collect Data: –Analyze & organize info. from experiments. –Check for error. Ex: Count the number of maggots on the meat samples in all jars.

Step 6 Form a Theory: –Explanation based on observations and experimental data Ex: Maggots are formed when flies are able to land on the rotting meat.

The Six Steps O H P E D T bservation ypothesis rediction xperiment ata collection and analysis heory

OBSERVATIONS: Flies land on meat that is left uncovered. Later, maggots appear on the meat. HYPOTHESIS: Flies produce maggots. PROCEDURE Controlled Variables: jars, type of meat, location, temperature, time Manipulated Variables: gauze covering that keeps flies away from meat Uncovered jarsCovered jars Several days pass Maggots appearNo maggots appear Responding Variable: whether maggots appear CONCLUSION: Maggots form only when flies come in contact with meat. Spontaneous generation of maggots did not occur. Scientific Method

Testing Your Skills! Story #1 There is a cabin on the side of a mountain. Three people are inside and they are dead. How did they die?

Story #1 Answer: They were killed in a plane crash. The three people were the pilot, co-pilot, and navigator. They crashed in snow storm. False Assumption: That the cabin was a mountain cabin. It was actually the cabin of a jetliner.

Story #2 It is a hot August afternoon. The location is the living room in an old Victorian mansion. The 7-foot window is open and the curtains are blowing in the breeze generated by the thunderstorm that just passed. On the floor lie the bodies of Bill and Monica. They are surrounded by puddles of water and broken glass. Neither Bill nor Monica has any clothing on. Close your eyes and picture the scene. How did they die?

Story #2 Answer: They suffocated. The storm winds blew open the window, which knocked their fish bowl off the table, and it crashed onto the floor. False assumption: That Bill and Monica are human. They are actually goldfish.

Story #3 A woman leaves home and makes three left turns. She returns home again. On the way, she passed two women with masks. Who were the two women?

Story #3 Answer: The umpire and the catcher. False Assumption: That the woman was walking on city streets. She really is on a baseball field

Themes in Biology

Diversity & Unity of Life: All living organisms share similar genetic make-up.

Interdependence of Organisms: Interactions of living organisms & their environment.

Evolution of Life: Change over time. Allows for variation between species.

Defining Life

Biology: Study of Life How do you define if something is alive?

All Living Things.... Are made up of cells Reproduce Are based on a universal genetic code Grow and Develop Obtain and Use Materials and Energy Respond to their Environment Maintain a Stable Internal Environment Change over time (as a group)

Organization: –Cells: smallest unit capable of life –All living things are composed of 1 or more cells.

–Unicellular: made of only 1 cell –Multicellular: made of many cells

Metabolism: all chemical reactions in an organism –Main source of energy: Sun

Homeostasis: –Maintaining stable conditions –Ex: body temp. always around 98 o F (37 o C)

Growth & Development: –Division & Enlargement of Cells –Specialization of Cells

Reproduction: –Essential for passing on blueprints (genes) from one generation to the next.

Assignment: Watch the following video clip: Write down 9 characteristics of life and name 1 organism you saw associated with each characteristic. –Use a separate piece of paper. –Turn in at end of video clip

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

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

Microscopes

Important Concepts Magnification: ability to make an image look larger Resolution: ability to show clear detail

Types of Microscopes Light Microscope: –A beam of light passes through lenses to produce an enlarged image.

Types of Microscopes –Use 2 sets of lenses: –Ocular lens - at top of scope, near the eye –Objective lens - located near specimen

Types of Microscopes –Total Magnification is found by multiplying the magnifications of the 2 lenses together: 10X x 40X = 400X (ocular lens) (objective lens) larger object

Types of Microscopes Electron Microscope: –Uses electrons instead of light. –Can magnify 100x more than light microscopes.