Intro to Living Environment

I. Nature of Life

A. Living things, organisms, are all different, but they share some common characteristics

B. These characteristics are called life processes.

I. Nature of Life

C. What are 9 characteristics that ALL living things have in common?

II. Life Processes

A. Nutrition – the intake of foodB. Transport – movement of materials in

an organism1. Cyclosis – mvmt of materials in

cytoplasm of a cell

C. Respiration – getting energy from food (aerobic / anaerobic)

D. Excretion – removal of wastes

II. Life Processes

E. Synthesis – combining small compounds into larger ones (make enzymes, fats, proteins)

F. Regulation – control of activities within an org

G. Growth – increase in size

H. Reproduction – create another org

III. Metabolism vs Homeostasis

A. Metabolism – all of the chemical reactions within an org (all life processes together)

B. Homeostasis – “same, level”, org trying to maintain a constant internal env while the outside env is changing

IV. Scientific Method

A. Used by scientists to solve problems

B. Steps1. State the problem – in the form of a

question “What is the effect of light on plant growth?”

2. Propose a hypothesis – “If ___, then___.” If light increases then the plant will increase growth

IV. Scientific Method

3. Design a Controlled Experiment – must have:a. Control Group – group where everything is

constant except for the variable being tested. “Plants exposed to normal light (or no light)”

b. Independent Variable – the factor changed by the scientist (amount of light)

c. Dependent Variable – the factor that responds to the change, the data (amount of plant growth)

IV. Scientific Method4. Make Observations – take measurements or use

senses and record in an organized manner (data table)

5. State a Conclusion – the answer to the problem, backed up by the data “Plants grow more in increased light.”

6. Repeat the Experiment – repeat to see if same conclusion is reached

C. To make an experiment more valid one needs to:

1. Repeat the experiment

2. Use more subjects

OBSERVATIONS: Flies land on meat that is left uncovered. Later, maggots appear on the meat.

HYPOTHESIS: Flies produce maggots.PROCEDURE

Uncovered jars Covered jars

Maggots appear No maggots appear

Several days pass

Redi’s Experiment on Spontaneous Generation

Controlled Variables:jars, type of meat,location, temperature,time

Independent Variable:gauze covering thatkeeps flies away from meat

Dependent Variable: whether maggots appear

CONCLUSION: Maggots form only when flies come in contact with meat. Spontaneous generation of maggots did not occur.

Spallazani’s Experiment

Gravy is boiled.Flask isopen.

Gravy is teeming with microorganisms.

Gravy is boiled. Flask issealed.

Gravy is free of microorganisms.

Pasteur’s Experiment

Broth is boiled. Broth is free ofmicroorganismsfor a year.

Curved neckis removed.

Broth is teeming with microorganisms.