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.

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 thatkeeps flies away from meat

Uncovered jars Covered jars

Several days pass

Maggots appear No maggots appearResponding 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 amountain. Three people are insideand they are dead. How did theydie?

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 98o F (37oC)

•Growth & Development:–Division & Enlargement of Cells

–Specialization of Cells

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

Levels ofOrganization

Levels of OrganizationOrganism

Groups ofCells

Cells

Molecules

Individual livingthing

Tissues, organs,and organ systems

Smallest functionalunit of life

Groups of atoms;smallest unit of most chemicalcompounds

Bison

Nervous tissue Nervous systemBrain

Nerve cell

Water DNA

Levels of OrganizationBiosphere

Ecosystem

Community

Population

The part of Earththat contains allecosystems

Community and its nonliving surroundings

Populations thatlive together in a defined area

Group of organisms of onetype 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.