Paper 5- Hutchinson and MacArthur 1959
Blog Author: Angel Sumpter
Hutchinson, G.E. and R.H. MacArthur. 1959. A theoretical ecological model of size distributions among species of animals. American Naturalist 93:117-125.
Blog Author: Angel Sumpter
Blurb author: S.K. Morgan Ernest
- University of Florida; Department of Wildlife Ecology and Conservation
- Interdisciplinary Ecology
- Associate Professor
- Runs the Portal Project long term ecological research site.
Paper Author 1:G.E. Hutchinson
- The Father of Ecology
- Primary Field of Research was limnology; the study of the physical, chemical, geological and biological aspects of lakes and other bodies of freshwater.
- One of the most influential biologists of the 20th century and was a beloved professor at Yale for 43 years.
Paper Author 2: Robert H. MacArthur
- His PhD thesis became the renowned 1958 Ecology paper on the coexistence of five species of warblers in northeastern coniferous forests
- MacArthur will be remembered as one of the founders of evolutionary ecology
- With Edward O. Wilson, he developed the view that an island flora or fauna could be viewed as a potential equilibrium between the arrival of new species and the extirpation of residents
Paper Summary:
- Main Question
- Background History
- Small animals comprise a large portion of groups with the largest number of species in an area. Though this logic follows the Eltonian pyramid closely, using the expression to explain how this happens in any area you choose to examine, seems unbelievable. An environment ideally does not seem able to provide enough room and usable resources to house such a large number of species all at once. Simple things that herbivores may need to survive (water and food) may be home to other animals.
- Goal
- To determine why there is more abundance in smaller animals compared to larger animals using an equation.
- Methods
- Examine/ consider fauna found in different areas of the world. Determine a contagious element within the environment and determine how it interacts with the environment. Conduct probabilities of the how the element will correspond to a niche. Determine how different elements correspond to environment and how the it affects the organisms that are within the environment.
- All of these are placed as variable into an equation/ model.
- Results
- Information- Theoretic Interpretation
- If niches are put into mixed group sizes, there is more diversity within the niches.
- Empirical Interpretation
- Three assumptions to keep in mind
- If each niche can only support one species than the quantity is an unsatisfactory measure of the function.
- If a single species is present, then there is a limiting probability.
- The number of available niches will increase to some sort of maximum and eventually a plateau of some size will decline to unity.
- Graph Results
- Mammal fauna of a certain kind can be built with a small amount of diversity if given sufficient range size.
- Large mammals going extinct may actually be due to human randomization of the habitat.
- Conclusion
- In brief, the data gained from actual application of the theory serve no actual importance to answering the main question. The results matched what information was known prior to the application and did very little to bring new knowledge to light. Based off information found, this theory could lead to modeling terrestrial faunas. Efforts in modeling such data will require much higher efforts in data collection with a new level of difficulty overall. Though very trivial, the theory might be able to possibly explain part of the reasons whole faunas have sizes dispersed the way they are. Data collected from this theory does not suffice as an answer, but as a stepping stone to other ideas.
- Question/ Comments
- What is a mosaic element? Google keeps telling me its an acoustic guitar...
- Mixed elements?
- I like how this entire math equation is based off of probability and assumptions. I know there is a lot more to it but wow, he made a lot of good educated guesses for him to be named a founder of ecology.
I also wonder what he infers as "mosaic elements". I have heard before that they applied those terms in Landscape Ecology to refer to small elements (habitat) contained in a large matrix of another element that is dominant in an area. I am not sure if they refer to that same kind of assemblage here too though.
ReplyDeleteI found interesting how they didn't find the pattern in dragonflies. Has this pattern in the right-skewed distribution been examined further in other very diverse taxa? Is it limited to mammals? what explanations have been proposed for this pattern?
I was surprised by their statement that "...the mammalia, being a highly diversified group, may perhaps provide a model of the terrestrial fauna of a locality as a whole". I'm very skeptical of this.
ReplyDeleteAlso, I read the wrong paper at first because #3 is also labeled as #5... I hope no one else made the same mistake. :|
So this paper was incredibly hard for me to read. The variables in his model are not defined in real people talk, so most of the model discussion was lost on me. I was confused when I read the summary as the body of the paper is all model and numbers and then he pulls out actual conclusions from the data. If I take the summary's word for it, these are important ideas- I was certainly taught this in my early biology classes. I did like that he alluded to humans causing a different signal and that he considers the future to be a macro approach to this.
ReplyDeleteI agree with Willow, this paper was really tough. I thought the uniform group of Odonata was interesting in comparison to the mammal faunas. He chose very random areas to analyze for mammal faunas, western Europe and Michigan. Was there a reason for choosing these areas?
ReplyDeleteDitto on the mosaic elements- it seemed like a big part of the theory statement and theoretical interpretation, so I was pretty confused in those sections. The author stated in the summary that the approximate could be formed if a complete faunistic list is used. Given this piece is from 1959, has this been done yet?
ReplyDelete*approximate form of the model
DeleteI agree with the other comments that this paper was hard to read. There was a lot of equations written out as text, but not a lot of explanation on what that actually meant. Going off of that, the summary and their conclusions seemed to come out of nowhere compared to the rest of the discussion in the paper.
ReplyDeleteThis paper is quite old (the 1950s), but pretty good for attempting to categorize and explain species composition with their geographic occupation. Also, I see a decent attempt to quantify actions from observation and units that are considered to be the best science. However, the terms and some theoretical statements are hard to follow. A mosaic element, in this case, is more referring a pattern of different species occupying multiple small patches of habitats fitted together. Each one of those habitats or patches are the elements. When it is puzzled, it is called "mosaic". I understand the importance of this paper but it will take so much time to go through the mathematical settings.
ReplyDeleteFor me it was also hard to follow the math part (and the overall argument) of the paper. Although the authors state that they are not expecting an exact match, it is hard for me to see a match between the model and the data for mammals, especially for the Michigan area.
ReplyDeleteWow this paper is pretty math-heavy. The authors kind of jump in right away with the equations without much explanation so I was pretty lost. I have heard of mosaic model but more in cellular biology so not really sure what the authors are referring to here.
ReplyDelete