1. Aim: What are some common laboratory techniques that are used in Living Environment?
Do Now:
Q1. Explain the importance of DNA.
Q2. Explain how plants obtain their food.

2. Paper Chromatography
Used for separation of plant pigment from solution, which means that plant solution is a mixture, which is separated into different components (ex. chlorophyll pigments)

3. Gel Electrophoresis Used to separate DNA pieces by size
DNA pieces (cut up by enzymes) are inserted into wells of chamber
Electric current put through the gel in chamber
One end of chamber is positive, one is negative
DNA always moves towards positive end, since it has a negative charge
Bigger DNA pieces move slower, so they will stay closer to the wells
DNA bands are formed on the gel
Different people will have different DNA banding patterns

4. Gel Electrophoresis
Can be used to determine evolutionary relationships, to solve crimes, in paternity suits, in gene testing for diagnosis of hereditary diseases

7. Let’s Analyze DNA Banding Patterns!
DNA evidence is found at a crime scene. There are 4 possible suspects for the crime. Can you figure out which suspect is the criminal?

8. Dichotomous Keys Used to help identify species
Ex. Bird X (unknown species)
Let’s practice! Identify the 4 unknown birds on the next slide!

10. Bird Identification What is the species name for Bird W?
What is the species name for Bird X?
What is the species name for Bird Y?
What is the species name for Bird Z?

11. Review Question

12. Question #1
Paper chromatography can be used to investigate evolutionary relationships. Leaves from a plant were ground and mixed with a solvent. The mixture of ground leaves and solvent was then filtered. Using a tooth- pick, twenty drops of the filtrate (material that passed through the filter) were placed at one spot on a strip of chromatography paper. This procedure was repeated using leaves from three other species of plants. A separate strip of chromatography paper was prepared for each plant species. Each of the four strips of chromatography paper was placed in a different beaker containing the same solvent for the same amount of time. One of the laboratory setups is shown below.
State one reason for using a new toothpick for the filtrate from each plant.  
State one way the four strips would most likely be different from each other after being removed from the beakers.
State how a comparison of these resulting strips could indicate evolutionary relationships.

13. Question # 2 Q: Which two bears share the most DNA or are most closely related?