Life & Scientific Method (Chpt. 3, 4)

Characteristic of Life

Common features shared by organisms

Life

Organisms that show metabolism and continuity

Characteristics of Life List

• Organisation: increasing complexity

• Nutrition: obtaining energy & materials from environment to live, grow & reproduce

• Excretion: removal of metabolic waste

• Responsiveness: ability to detect changes in environment & altar behaviour accordingly

• Reproduction: ability to make new organisms of same type

Increasing complexity of organisation

Molecules, organelles, cells, tissues, organs, organ systems, organisms, populations, communities, ecosystems, biosphere

Not included in Characteristics

• Growth: increase in size/number of cells in an organism

• Respiration: production of energy in ATP form by breaking down complex molecules into simple molecules

• Movement: self-generated change of position in response to internal/external variations in environment

metabolism

Sum of chemical reactions that occur within an organism

continuity of life

Living things arise from other living things of the same type

Steps of Scientific Method

observation, hypothesis, test, conclusion.

Experiment factors

1. Data

2. Replication

3. Control (conditions optimal for result)

4. Dependent variable (variable being examined)

5. Independent variable (changed over course of experiment)

6. Fair test (both male & female subjects to ensure not chance, test and placebo groups with double-blind testing)

Limitations of Scientific Method

1. Present knowledge

2. Basis of investigation

3. Changing the natural world

4. Dishonesty & bias

5. Accidental discovery

6. Instruments

7. Sample size

if conclusion false

modify hypothesis, repeat

if conclusion true

make more detailed hypothesis, repeat; publication, law

In drug trials

test group (get drug), control group (placebo), double blind (neither doctor nor recipiant know; removes any bias)