You are here

drosen's blog

Observational differences between #25

Submitted by drosen on Fri, 02/16/2018 - 14:48

Observational Differences:

1. The bottom panel is more blurry than the top panel.

2. The pictures of pannel1&2A and 1&2B are not the same distance from the camera in the bottom panel.  This is due to the differnet bee sizes as well as the different leaf sizes. 

3. The Flowers in 1 and 2 B panels are not the same color.

4. There is no glass rim in 1A or 1B

5. There is no gray surface in 1A or 1B

6. The width and color of the bees do not appear to be consistent betwee the 2panels.

7. There appears to be a light source illuminuating 1A and 1B 

8. The leaves in panel A appear to be facing in different directions. 

9. The bee is resting in a flower in Panel 2B however it is residing on leaves in 1B


1. Different cameras were used given the degrees of clarity.

2. Different bees were used given the differences in size and color

3. The speciments used in the bottom photohraph are not the same as the top given the array of differences.

4. The photograph was taken at a later date due to the flowers having changed.

5. The photograph was taken in a different location or at a different time of day due to the degrees of lighting differences. 


Starting the observational paragraph:

Perfect replication of any experiment or action is an unfair expectation in experimental science. The complexity and wide array of variables that simply cannot be controlled will always contribute to indescrepancies between data.  However, these differences should be expected and properly acknowledged or explained. Here we see that even a brief comparison of the two figures allows one to find several discrepencies, including distance from the material, level of focus,  time of day and location of the photograph, that are likely secondary to variables not approrriately discussed in the methods section above.

For the capture of clear, useful information while photographing detailed objects, such as insects, the distance one captures the image and the level of focus used help one construct clear and informative images. Based on the dife









Inference vs. Observation.

Submitted by drosen on Fri, 02/16/2018 - 13:44

At the hospital; we typically see patient's that display a wide variety of observable symptoms that are then used to make inferences pertaining to their underlying cause. A classic example would be a rash. Typically, these are most offten treated as either a reaction to a fungal source or an allergic reaction to a new chemical.  The observable symptoms,  i.e the rash and any associated chatacteristics such as the type of nodules, scale, color etc all allow the provider to make an educated guess, or inference,  as to the method of treatment used (topical steroid if allergic or a topical antifungal if tinea based).

Perfect Paragraph - Stable isotope analysis.

Submitted by drosen on Fri, 02/16/2018 - 10:11

Stable isotope analysis is a revlutionary analytical process that has several implications on both the ornithological field and conservative movements worlwide. This technique allows for the analysis of isotope concentrations that collect in the tissues of species following meals and this information can be used to make inferences on location given the geographic predicatilbity of these isotopope concentrations. This is atypically powerful with avian species as their feathers are unique and metabollicaly inert once they reach maturity. Similar to fossills, this leaves a lasitng mark that can be analyzed months after the standard isotopes would have naturally been released in normal tissues. Conservatonalist advocates have used this evidence to support movements for the protection breeding and molting grounds that can be thousands of miles away from the speices that are affected by their destruction.

Beak Evolution Conclusion for the Podos Article.

Submitted by drosen on Thu, 02/15/2018 - 22:08

Podos states that his findings were consistent with the proposed vocal constraint hypothesis, which essentially states that as beak size changes, various levels of beak mobility will in turn change song quality and sound. His data suggests that the change in sound was correlated to both beak size as well as mass, however he later presented contrary evidence for the mass’s effect on this. He then proposes that several factors, including resource changes leading to beak size adaptation, as well as cultural evolution and various acoustic environment. Finally, he suggests that the importance of prezygotic isolating mechanisms (mating songs) are indirectly influenced by adaptive diversity of beaks. This particular experimental group is powerful as there is a high number of species within a relatively small area and opportunity for hybridization. Despite this, there has been rapid speciation and he believes that his songs help ensure “correct” mating occurs.

Wing assisted Incline Running and the evolution of Flight

Submitted by drosen on Thu, 02/15/2018 - 19:55

The initial question presented at the beginning of the article pertains to the evolution of flight in regards to evolutionary advantage during the intermediate stages. There are two rival theories; the”tree down” hypothesis as well as the “ground up” hypothesis that support conflicting ancestral behavior that eventually transitioned to modern flight. Dial’s interpretation of his data, specifically the correlation between the WAIR facilitating movement on coarse surfaces, such as tree bark, as well as the change in the birds’ center of gravity while performing WAIR, both support the ground-up hypothesis as these qualities seem to be an escape mechanism for terrestrial birds. In addition, Dial goes on to suggest that proto-birds, such as archaeopteryx, had bone structure to support antero-posterioral movement, which is ideal for the movements necessary for WAIR utilization. Furthermore, he proposes that wing-angle adjustment used for varying levels of incline could have also been used as a tool for controlled descent and body manipulation while in mid air, which could have also contributed to the eventual evolution of flight.  

Stable Isotope Analysis

Submitted by drosen on Wed, 02/14/2018 - 21:09

Stable isotope analysis is a process where one analyzing varying levels of common isotopes in tissue levels. This information is useful as concentrations of various isotopes are predictable and tissue changes are accumulated via diet. However, each isotope has a turnover rate which can range from days to months, which may skew any data being used to determine locations of breeding or molting grounds. Feathers are an exception to this turnover process as they rapidly develop and then become metabolically inert, essentially freezing their isotope concentrations in place. Then, using, a mass spectrometer, one can identify what was consumed during feather development and then use this information to determine where molting or breeding grounds are. While this is still an inaccurate process and unrefined process,  there is opportunity for more improvement with multiple isotope analysis as well as more accurate geographical isotope predictions.

Correlated evolution of morphology and vocal signal structure in Darwin's Finches

Submitted by drosen on Wed, 02/14/2018 - 19:04

Correlated evolution of morphology and vocal signal structure in Darwin's Finches


In this article, Podos challenges the classical theory that mating signal (i.e song) evolution is an accidental byproduct of speciation operating on other environmental factors. Specifically, he refers to beak morphology and questions how the adaptive diversification of beaks has influenced the evolution of song quality by either enhancing or constraining vocal abilities. Considering he begins the article by noting that songs are often used for mating, I infer that he suspects that evolutionary diversification of break size and shape (secondary to ecological changes) may indirectly lead to speciation by changing mating calls.

Subscribe to RSS - drosen's blog