# BI376 Final Project
Emily Larson & Mark Young

## Proposal

For our project, we plan to investigate variation in Monstera leaf shape. In a 2013 paper, Chris Muir presents a model to explain the evolutionary favorability of leaf fenestration for the sunfleck dependent Monstera. However, he ignores between leaf variation in fenestration. Monstera are characterized by a multi-layer canopy of different sized leaves with different numbers of cuts. We plan to capture leaf shape with geometric morphometrics and relate it to degree of fenestration and light recieved (we are using height as a proxy). Muir's model indicates that light conditions are critical to the selective advantage of fenestration. Thus, any observed relationship between light and leaf shape and fenestration may expose phenotypic plasticity in support his model. Specifically, we hope to see investment in fenestration and shape change only in high-light leaves, as his model predicts that fenestration is only beneficial for leaves recieving enough sunflecks. We also hope to see changes in leaf shape to maximize ground area (includes holes) in high light leaves, as this should further increase degree of fenestration.

We plan to collect our data from Monstera deliciosa found on campus. Emily has one with 25 leaves and there are others in Arey and Olin. However, while Emily's resides in relative shade, the others are grown in greenhouse conditions. The differences in light conditions may confound our analysis so we have not yet decided to incorporate the Arey and Olin plants. In addition, we are interested in differences between leaves on the same plant, not differences between plants.

## Annotated Bibliography
Muir, C. D. How did the swiss cheese plant get its holes? Am. Nat. 181, 273–281 (2013).

- This paper focuses on the evolutionary favorability of leaf fenestration in the context of understory tropical plants, such as Monstera. Muir observes the dependence of Monstera on sunflecks (random patches of light breaking through the canopy) and argues that although fenestration does not increase the expected value of light absorbed by an individual, it does decrease variance. Population genetics shows that decreased variance in individual fitness is evolutionarily favorable (diminishing returns of absolute to relative fitness ratio) and Muir builds a model to show how fenestration can lead to decreased variance. He further supports his point with observations of leaf heteroblasty in climbing Monstera, which are no longer in growth conditions where his model predicts fenestration to have a significant fitness benefit.

Sterck, F. J., Poorter, L. & Schieving, F. Leaf traits determine the growth-survival trade-off across rain forest tree species. Am. Nat. 167, 758–765 (2006).

- This paper used a Bolivian rain forrest data sample to build a model to show that overall leaf area was associated with height variation, and that leaf survival rate is a good indicator of overall plant survival. Additionally, fast growing plants did poorly overall in a variable light enviroment.

Zotz, G., Wilhelm, K. & Becker, A. Heteroblasty-A Review. Bot. Rev. 77, 109–151 (2011).

- This review paper covers theory behind leaf heteroblasty. It appears to be useful for better understanding molecular mechanisms and evolutionary pressures behind variance in leaf shape. It is also cited by Muir as a useful read.

## Other notes
What boundary layer thickness is \:
https://gpnmag.com/article/the-boundary-layer-and-its-importance/

## Our Model

- fenestration increases the ratio of ground area to leaf area
- approximate ground area with centroid size
- count pixels for leaf area
- degree of fenestration = ground area / leaf area
Muir:
- fenestration is costly
- fenestration allows leaves to capture pieces of more sunflecks, but less of individual ones -- decreases variation in sun capture but keeps expected sun capture the same
- low variation in expected capture is favorable (decreasing returns of relative fitness)
- leaves have different numbers of holes, different sizes, maybe different shapes?
- Is the variation in shape / degree of fenestration on a plant random/ correlated with size? Or is it driven by environmental input (light)?
- Muir's model indicates that it is favorable to put energy into fenestration only when a plant is recieving enough light (other shade plants dont).
- A plastic relationship between fenestration and light would support Muir's model
- Does leaf shape matter? Are certain shapes easier to fenestrate? Shape change and increased fenestration in high light leaves would indicate a plastic response to maximize fitness.
- leaf shapes that maximize width of slits would increase degree of fenestration (pointy leaf to wide leaf)

## Landmarking Guide

Want points at connection to stem, furthest back, widest, and tip, as well as halfway points between widest and tip.

1) use line tool to draw line between widest points


2) Connect with line down stem to find midpoint between widest point and leaf tip

3) Use angle tool to find points at halfway between widest point and tip

4) Measure scale (10 cm)


5) Place 8 Landmarks