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Methods

- Twelve planaria (Dugesiadorotocephala) are placed into a petri dish (10 mm in diameter).
- Individual Daphnia magna were observed using a microscope.
- A mortar and pestle, sand, and acetone were obtained to prepare the green algae (Ulva sp.) for the experiment.

Needs to be past tense!

What type of microscope?

Don’t list equipment or supplies! Talk about how you used them.

Methods

- One clam worm (Nereis virens) was placed into a 1 L beaker containing 60% saltwater.
- Myosin was extracted from minced muscle samples (10-30 mg) at 4° C for 60 minutes in 40 volumes of a gel sample buffer.

How much saltwater was in the beaker?

What was the composition of the sample buffer?

Figure 1. Average percent change in heart rate of Daphnia magna exposed to 0.1% caffeine, 1% nicotine, and 4% alcohol. Error bars are +/- 1 S.D.

Figure 1. Average percent change in heart rate of Daphnia magna exposed to 0.1% caffeine, 1% nicotine, and 4% alcohol. Error bars are +/- 1 S.D.

- As you can see in Figure 1, …
- Figure 1 shows …
- The results for the average percent change in heart rate of Daphnia magna were summarized in Figure 1.

Present tense!

Figure 1. Average percent change in heart rate of Daphnia magna exposed to 0.1% caffeine, 1% nicotine, and 4% alcohol. Error bars are +/- 1 S.D.

- The average percent change in heart rate for nicotine was much higher than that for caffeine (Fig. 1).
- The application of 1% nicotine led to a large decrease in heart rate (Fig. 1).

Figure 1. Average percent change in heart rate of Daphnia magna exposed to 0.1% caffeine, 1% nicotine, and 4% alcohol. Error bars are +/- 1 S.D.

- The average percent changes in heart rate of the Daphnia magna exposed to nicotine was much greater than the changes in heart rate experienced by the Daphnia exposed to caffeine and alcohol.

Figure 1. Average percent change in heart rate of Daphnia magna exposed to 0.1% caffeine, 1% nicotine, and 4% alcohol. Error bars are +/- 1 S.D.

- The average percent change in heart rate of the Daphnia magna exposed to 1% nicotine was -35%, which was greater than the changes in heart rate recorded for the Daphnia exposed to 0.1% caffeine (-0.5%) and 4% alcohol (-21%) (Fig. 1).

Figure 1. Average percent change in heart rate of Daphnia magna exposed to 0.1% caffeine, 1% nicotine, and 4% alcohol. Error bars are +/- 1 S.D.

- The standard deviations for the caffeine, nicotine, and alcohol data sets were 4.0%, 9.3%, and 8.2% respectively.
- The error bars of the caffeine and nicotine data sets did not overlap, but those of the nicotine and alcohol data sets did.
- The error bars of the nicotine and alcohol data sets overlap. Thus, these data are insignificant.

Figure 1. Average percent change in heart rate of Daphnia magna exposed to 0.1% caffeine, 1% nicotine, and 4% alcohol. Error bars are +/- 1 S.D.

- The average percent change in heart rate of the Daphnia magna exposed to 1% nicotine was -35%, which was significantly greater than the change in heart rate recorded for the Daphnia exposed to 0.1% caffeine (-0.5%) (Fig. 1). The change in heart rate of the Daphnia when exposed to nicotine was also greater than the change recorded for these organisms when they were exposed to 4% alcohol (22%), but this difference was not significant (Fig. 1).

Figure 1. Average percent change in heart rate of Daphnia magna exposed to 0.1% caffeine, 1% nicotine, and 4% alcohol. Error bars are +/- 1 S.D.

- The average percent change in heart rate of the Daphnia magna exposed to 1% nicotine was -35% (Fig. 1). Thus, nicotine decreased the heart rate of these organisms, a result that supports my hypothesis.
- Caffeine slightly decreased (-0.5%) the heart rate of Daphnia magna (Fig. 1), which is opposite of its effects in other organisms.

Fig. 2. Percent change in weight of Nereis virens placed in different salinities at 15 minute intervals over 90 minutes.

Fig. 2. Percent change in weight of Nereis virens placed in 40%, 60%, 80%, 100%, and 120% saltwater at 15 minute intervals over 90 minutes.

The percent change in weight of the Nereis virens placed in 40%, 60%, and 80% saltwater increased steadily over the course of 90 minutes (Fig. 2).

Fig. 2. Percent change in weight of Nereis virens placed in 40%, 60%, 80%, 100%, and 120% saltwater at 15 minute intervals over 90 minutes.

The percent change in weight of the Nereis virens placed in 40% saltwater increased from 6.7% to 26.2% over the course of 90 minutes. Similarly, the percent change in weight of the worms placed in 60% and 80% increased over the same time period (60%: 3.1% to 18.2%; 80%: 2.7% to 9.5%) (Fig. 2).

Fig. 2. Percent change in weight of Nereis virens placed in 40%, 60%, 80%, 100%, and 120% saltwater at 15 minute intervals over 90 minutes.

Results

- Just the facts – data
- No interpretation or conclusions
- Mention the organism used and its scientific name
- Reference figures
- (Fig. 1)
- Figures must stand alone

Results

- Significance
- Non-overlap of error bars
- Statistical tests – p values

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