November 24th is Evolution Day, which celebrates the publication of On the Origin of Species by Charles Darwin in 1859. Darwin’s theory of evolution is one of the central concepts in biology.
Experiments in comparative physiology are an excellent way to teach concepts in evolutionary biology. The Vernier Biology Department developed an experiment that investigates the comparative physiology of snails and fish.
Did you know you can now use our digital microscopes and cameras with LabQuest 2? Our USB Digital Microscope and the Celestron Digital Microscope Imager, a drop-in digital microscope camera, work with computers or Chromebooks. They have been very popular with biology teachers. We know that many schools can’t have a computer at every microscope station, so we have added the ability to capture images from these cameras on LabQuest 2.
Starting with LabQuest App version 2.6, you are able to view and save images from both of these products. Simply connect the camera’s USB cable to LabQuest 2 and launch the Camera App. You can get very clear images that are easy to see and save. With the addition of LabQuest Viewer computer software, you can project the image for the entire class to see or monitor what your students are seeing at each lab station without leaving your desk. LabQuest Viewer for iPad is also available on the App Store.
We know that many biology teachers use images from microscopes and dissecting scopes in their teaching, and we hope this new feature in LabQuest 2 makes it even easier!
John Melville, our Biology Staff Scientist, has created a set of files for Logger Pro and LabQuest App that use digital filtering to improve EKG and EMG traces when using our EKG Sensor. Logger Pro 3.8.6 and LabQuest App 2.2 both offer calculated columns that can be used to filter sensor data. Digital filtering is also referred to as signal processing and is a common tool that many biomedical engineers use to improve signal quality of physiological data.
In Logger Pro, the new files that utilize digital filtering can be found in the EKG Sensor folder, which is located inside the Probes & Sensors folder. You will find a low-pass filter file for reducing distracting, rapid variations in signals, a high-pass filter file to reduce the effect of a varying baseline on signals, and a time-decay filter file that applies a simple adjustable time constant to the data, smoothing out rapid fluctuations while preserving long-term trends. The parameters of each filter can be adjusted using arrows in the parameter control, which is found just below the digital meter. These filter types can be used to improve the signal quality of EMGs and EKGs. An example EKG trace using the low-pass filter file is shown above. Similar files for use on LabQuest can be downloaded below.
Now that neuroscience is a topic covered in one of the “big ideas” in the new AP Biology curriculum, many teachers have been asking how Vernier sensors can be used to teach concepts related to neuroscience.
Our biology staff scientist, John Melville, has been working with our new LabQuest Mini and has found a way to integrate video analysis into a simple muscle physiology experiment. EKG sensors are attached to the bicep and forearm muscles to record muscle activity. A Low-g Accelerometer is then attached to the wrist to measure joint angle. The video capture feature in Logger Pro is then used to synchronize video from a DV camera and the physiological data from the LabQuest Mini. The subject is filmed performing a simple bicep curl. Students can then clearly see that muscle activity precedes movement of the arm and that the forearm muscle activity precedes activation of the bicep.
Fluorescent molecules are compounds that absorb light of one wavelength, then re-emit light at a longer wavelength. This emitted light can be quantified using fluorescence spectroscopy. Molecular and cellular biologists use fluorescent compounds to label proteins, gels, and even cellular organelles. In many ways, fluorescent compounds have revolutionized research in the life sciences.
With its increased frequency response and external grounding pin, our new and improved Instrumentation Amplifier can now be used to record the electric signal from an electric fish with four easy steps.