Experimental Design and Living Organisms Characteristics of Organisms

Experimental Design and Living Organisms

Characteristics of Organisms

Organisms are organized They have a structure

Organisms reproduce They produce offspring that are similar to themselves. This is essential for the survival of the species

Organisms change over their life They grow and die.

Organisms respond to their environment. • A stimulus in the environment causes a response.

Organisms use energy to move, grow and reproduce.

Organisms adapt to their environment over generations. Mosquitoes and DDT

Experimentation with Organisms • Observations lead to questions • Questions can lead to a hypothesis

How do we test a hypothesis? • Control groups and experimental groups. – Control group provides a comparison – Experimental group is exactly the same as a control, except for the factor you want to test. Hypothesis

Test one factor at a time. • Independent variable – The factor that you change. • Dependent variable – The response of the organism.

Procedure One step at a time. • Enough information for replication • List your constants: temperature, amount of salt, time frame for experiment. • Replicate

Observations Quantitative Open Brine Unhathed Shrimp brine Eggs shrimp eggs 0% 1% 5% total percent

Conclusions

Replication • Others need to be able to do your experiment and get the same result.