2
Senses and Hormonal Effects on Physiology Lab
Introduction
It is no secret that all animals use their senses to navigate around the world in a way that benefits them. However, variation occurs either because of age, genetics, or the need of a sense in that area. In this lab this variation will be tested through a high frequency hearing test, as well as touch sensitivity. In the first case, hearing ability can decrease because of natural decrease in hearing ability with age, or because of damage due to loud noises. We’ll test touch sensitivity on different body parts.
For the second part of this lab, hormones and pheromones will be tested. Ants communicate greatly through pheromones in their daily lives, whether it is to find resources, inform of danger or communicating an action necessary. Mammals also use pheromones to communicate with others. In addition, internal communication within the body occurs using hormones. We will be using rats to test this out. Because rats are highly sociable animals, hormone and pheromone production will occur based on the interaction received.
Pre-Lab Questions
1. What is the hearing range of a human and what frequencies are lost with age?
2. Name one part of the body that is relatively precise at detecting touch, and one that is relatively poor at detecting touch. Explain why the difference occurs.
3. Name one other group of animals beside ants that uses pheromones to communicate. What kind of information can they learn through pheromones?
4. Explain the functions of testosterone, estrogen, oxytocin, and cortisol as it relates to social behaviors in mammals.
5. Explain modulatory communication in ants, or any other social insects.
Equipment
- Sonic Tone Generator
- Phone
- Headphones
- Calipers
- Syrup
- Lavender Oil
- Pipets
- Water dish
- Water
- 6 rats of different ages and sexes
- Cage for rats
Activity 1: Hearing range test
Hypothesis 1: Ability of hearing higher frequencies will decrease with age.
Download an app called “Sonic Tone Generator” on your phone. Connect headphones to your phone, record the highest frequency that is audible to you. Some phones have a limited range of playable frequencies, but if your model allows it, headphones might not be necessary. When playing the sound, record the last tone that you hear instead of the last “noise”. This is because some sound artifacts may occur when playing the frequency, such as when first pressing the button.
| Name | Age | Highest frequency heard in Hz | Average time each day exposed to loud noise (headphone usage, machinery, etc.) |
| 1 | |||
| 1 | |||
| 1 | |||
| 1 |
Activity 2: Touch sensitivity
Hypothesis: Fingertips will be more accurate than other parts of the body tested.
Grab a pair of calipers and take turns conducting the experiment. Decide who the test subject will be and have them sit with their eyes closed, while the tester touches the calipers to their skin. Record the length at which the subject stops feeling like there is two points, and instead starts feeling as if there is only one. Periodically touch only one point of the caliper on the skin so it is harder to guess how many points are present. Try it out on fingertips, back of the hand and shoulder area.
| Name | Fingertip in mm | Back of hand in mm | Shoulder in mm |
| 1 | |||
| 1 | |||
| 1 | |||
| 1 |
Activity 3: Ant and pheromones (not vertebrates but widely available)
Hypothesis 1: Putting an obstacle on an ant trail will disturb the existing and new pheromone trails, especially if it’s a strong smell.
Hypothesis 2: Ants will change their behavior through modulatory communication in response to stimuli.
Grab some syrup, water in a container and the lavender oil bottle. Go outside and locate an accessible trail of ants. Block the existing path of ants by dripping the water across the path. Observe the behavior as they find a new path. Once the water dries, observe if the ants resume their previous path. Repeat the same with lavender oil.
On a different part of the ant trail, put three syrup drops on the ground close to the trail so the ants can find it. Make sure the drops are similar in size and are apart enough to draw a small circle around them. Leave the first drop for control, drip water around the second syrup drop, and lavender around the third syrup drop. Observe the behavior again. Lastly, physically disturb one of the ants and observe how it communicates about the event with others.
| Event | Ant behavior observed (be as precise as possible) |
| Water blocking an existing path | |
| Water drying after blocking an existing path | |
| Lavender blocking an existing path | |
| Lavender drying after blocking an existing path | |
| Syrup with nothing around it | |
| Syrup surrounded by water | |
| Syrup surrounded by lavender oil | |
| Physical disturbance |
Activity 4: Rat Communication
Hypothesis: A more confident rat will respond to newly introduced rats of different age and sex with more enthusiasm than a less confident rat.
Six rats will be used in this lab and the behavior of a known confident and a known less confident rat towards new rats will be observed. First, the less confident rat will be put into the animal observation room. A cage with a familiar, more confident rat will be set in the room, and the behavior of the less confident rat towards it will be observed from the outside for 5 minutes. Repeat with a cage containing a young female, middle-aged female, older female and an older male. Next, cage the less confident rat and observe the behavior of the confident rat towards new rats.
| Rat type | Confident rat | Less confident |
| Less confident male rat | Familiar with each other | xxx |
| Confident male rat | xxx | Familiar with each other |
| Young female | ||
| Middle-aged female | ||
| Older female | ||
| Male old |
Post-Lab Questions
1. Did the maximum detectable frequency decrease with age? If any outliers occurred, explain how the average amount of noise per day can cause this difference.
2. Which part was best at detecting touch? How is this related to daily function?
3. Did ants return to the past trail after it was previously, but no longer blocked by water? What about lavender oil? Explain how this can disrupt the ants besides creating a physical barrier.
4. Did ants seem to get “infected” with following or doing a certain behavior? How was this information passed between the ants and which body part was used?
5. Relate to how the rats interacted back to hormones. Which hormones might be influencing the behaviors shown by different rats?
