Johnny Bravo’s square jaw vs Popeye’s round jaw: A scientific explanation

From left to right, popular cartoon characters Ferb, Phineas, Popeye, and Johnny Bravo.

Do you ever scratch your head and roll your eyes at the ridiculous shapes of cartoon characters? While it can’t be confirmed that Phineas and Ferb have legitimate jaw bones, there may be a scientific explanation to Popeye’s rounded jaw to Johnny Bravo’s square jaw.

A recent study published online in Scientific Reports on April 16, 2018, validated a significant association between mandibular shape and jaw muscle cross-sectional size. In other words, researchers found that thicker jaw muscles produced broader, bigger, and more rectangular jaw bones.

Previous studies have shown that craniofacial skeletal form, or the structure of the bones of the face and jaw, is influenced by mechanical loading. Just as your leg bones get stronger from running, and arm bones get stronger from lifting weights, jaw bones get stronger from chewing. The specific shape of the mandibular bone is also determined by the forces applied to it throughout development. So, you might get your dad’s square jaw through genetics, but you also have a square jaw because of the foods you eat regularly.

Jaw muscles
The temporalis muscle and master muscle of the skull. Credit: Sella-Tunis et al. Labels added.

Scientists at Carmel Research Center in Israel measured jaw shapes and jaw muscles in 382 adult patients by utilizing CT scans. These scans allow for visualization of both bone and muscle, and they specifically looked at (1) the temporalis muscle, which is a large, round muscle that reaches from the side of the skull to the side of the face, and (2) the masseter muscle, which stretches from the lower jaw to the upper jaw.

Jaw bone
Comparison of jaw bone size and shape. Credit: Sella-Tunis et al. Labels added.

Independent of gender and accounting for relative size of individuals, researchers found that larger jaw muscles resulted in a wider ramus, a bigger coronoid projection, a more rectangular base, and a more rounded basal arch. Alternatively, smaller muscles produced a skinnier ramus, a smaller coronoid projection, a narrower and angled base, and a more triangular basal arch (see picture above).

This research can be used in anthropology contexts. Researchers suspect that  hunter-gatherer populations had harder diets, comprised of nuts and meat, which generate larger muscles and produced a stronger jaw line, while agricultural groups that ate more vegetation had skulls that resembled the jaws with smaller muscles. According to this data, it is plausible that Popeye’s spinach diet led to the growth of his softer, rounder jaw, and I would guess that Johnny Bravo is a fan of tougher foods.


Sella-Tunis, T., Pokhojaev, A., Sarig, R., O’Higgins, P., & May, H. 2018. Human mandibular shape is associated with masticatory muscle force. Scientific Reports 8. [doi: 10.1038/s41598-018-24293-3].



Restoration of the Gulf Takes More Than Money

Sediment-laden water pours into the northern Gulf of Mexico from the Atchafalaya River in an image taken by the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Aqua satellite on April 7, 2009.
Source: Nasa

Researchers at University of Waterloo published a study in Science in late March of 2018 giving new insight into the fact that restoring the water quality in the Gulf of Mexico is harder than originally thought. The Gulf of Mexico contains a hypoxic or dead zone, an area found in bodies of water that have extremely low levels of oxygen due to excessive nutrient pollution from human activities. Recently, attempts have been made to reduce the size of the Gulf’s dead zone, but despite these investments of large amounts of money, researchers have concluded that the legacy of nitrogen is so intense that these goals are unrealistic.

This dead zone is due to large quantities of nitrogen being carried through rivers and streams across the North American corn belt to the Gulf. Massive algal blooms sparked by the concentration of nitrogen leads to oxygen depletion, making it more difficult for marine life to survive. Due to its continual expansion, this area is approximately the size of New Jersey, and will continue to grow unless drastic measures are taken. Major changes in agricultural and river management practices must be made in order to see any type of improvement of water quality.

Researchers compiled and analyzed more than two centuries of agricultural data, showing that nitrogen has been accumulating in soil and groundwater due to intensive agricultural production. The water quality of the Gulf of Mexico has been declining since the 1950’s. It’s hypoxic zone is mainly caused by use of fertilizer and intensive livestock production. Manure and fertilizer are both rich in nitrogen, and can easily enter watersheds through runoff.

After this analysis, researchers modeled the results and concluded that even under best-case scenarios where effective conservation measures are implemented instantly, it would take over 30 years to restore the Gulf of Mexico through depletion of excess nitrogen. They continue their analysis to phosphorus, which is a major instigator of algal blooms in inland waters

The need for intensive agricultural production is only increasing, nitrogen quantities will continue to rise do to this, creating a massive problem for marine life around the globe. Effective policy must be implemented to curb the growth of this massive dead zone in the Gulf of Mexico, which imposes a great risk on marine ecosystems all over the region.

K. J. Van Meter, P. Van Cappellen, N. B. Basu. Legacy nitrogen may prevent achievement of water quality goals in the Gulf of MexicoScience, 2018; eaar4462 DOI: 10.1126/science.aar4462

How to Feed 7.6 billion People

Can our current farming systems keep up with a growing population, while also protecting the land we eat from? It’s a tough question, but a study published earlier this year suggest it is possible. The research focuses on farms in the Northern Plains of the United States, specifically those under a conventional corn production system versus those under a regenerative agriculture system. Farms included in the study that were using regenerative agriculture practices never tilled their fields, did not use insecticides, grazed their livestock on the cropland, and grew a mix of cover crop species. The conventional farms included in the study practiced tillage, used insecticides, and left the soil bare after harvest.

Researchers collected soil cores from each farm to determine the amount of organic matter within. This, along with the abundance of pest, yield, and profit were assessed. Yield in this case was the gross revenue. The study found that regenerative agriculture systems had 29% lower grain production, but had 78% higher profits- two times that of conventional agriculture. In addition, there were ten times the amount of pest on fields treated with insecticides, than those that were not. All of this is because regenerative agriculture allows for nature to do its job. Spraying insecticides on a field is not only harmful to the environment, but is ineffective. Insects can adapt to new chemicals and will persist even more when their natural predators are eliminated by insecticides. Biodiversity within cropland can reduce the amount of pest and their persistence. Regenerative agriculture raises organic matter in the soil which in return allows for increased soil infiltration, diverse soil life, less fertilization, and lower input costs. Also, systems that incorporate livestock and cropland can see higher profits from the livestock as they can feed on the cover crops, reducing fodder input and allowing more of the corn harvested to feed humans.  Conventional farming sees smaller profits because of the high seed, fertilizer, and insecticide investments.

Regenerative agriculture has become a sustainable alternative to traditional farming because it provides ecosystem services, while producing higher profits than the more input intensive conventional system. Like many recent studies, the outcomes favor the unconventional farming method and show increased profitability and farm health for those using regenerative agriculture. The abundance of new research in agriculture shows that we can feed the world if we simply change how we grow our food. There needs to be a shift in farming values that prioritize the land, resources, and the quality of food over high yield numbers.

Source: LaCanne, C.E., and Lundgren, J.G. 2018. Regenerative agriculture: merging farming and natural resource conservation profitably. PeerJ 6e4428.

Photo source:  Flickr

Coffee, Cocoa, and Cost Efficiency


A group of researchers from the Netherlands have conducted a study comparing the outcomes of coffee and cocoa farming in a shaded agroforestry setting versus a conventional full sun plantation setting. Agroforestry is the practice of integrating trees and shrubs with crops to create environmental and economic benefits, without the use of agrochemicals and high densities of monocultures. The 2017 study attempted to compare the two methods of farming by calculating price per kilogram, yield, net return and revenue, and biodiversity performance.

After analyzing 23 studies, the researchers found some promising information. Profit and cost efficiency was greater for small, shaded farms. The average net return for shaded systems was 23% higher than conventional systems, resulting in a higher profit per hectare. In addition, the price per kilogram was 18% higher from shaded farms- potentially due to higher quality and environmental certifications. However, the conventional non-shaded farms had a greater yield. The lower yield produced by shaded farms, however, is said to be compensated for by the increased biodiversity and protection provided by the trees. The addition of trees in the growing of coffee and cocoa can prevent crop disease and enhance the soil fertility, acting as a natural fertilizer and soil stabilizer.

The study concluded that more research would need to be conducted to further demonstrate the relationship between biodiversity and shaded systems, as well as the financial relationship with shaded systems. Information from this study may serve to induce similar studies so we can fully understand how agroforestry may benefit an agricultural system, the environment, biodiversity, and income of the 30 million coffee and cocoa smallholders predominantly from developing countries.


Source: Rosalien E. J., Pita A. V., Maria J. S., René G.A. B. 2017. Shaded Coffee and Cocoa – Double Dividend for Biodiversity and Small-scale Farmers. Ecological Economics 140: 136-145

Photo Source: Department of Foreign Affairs and Trade 

Saving Soil: Case studies from the Great Plains

soybean field

They say you don’t know what you have until it’s gone, and that may very well be the case of Great Plains farmers and ranchers who are experiencing significant losses of soil due to erosion. A recently published study uses numerous case studies from the Great Plains states to highlight the importance of soil health to ensure soil security. Soil security recognizes the role soil has in meeting today’s global challenges of food security, water security, and climate change. Soil health influences the goods and services we receive from the soil, so it is necessary that we understand how soil is being both compromised and sustained. By making growers and consumers aware of the externalities of degraded soil health, we can hope to better the agricultural system. 

Land used for cultivation has increased over the last several years in the area of interest, drastically changing the landscape. Clearing land for crop use by conventional means, entails the removal of grasslands and perennial crop cover such as grasses and trees. In doing so, the soil becomes loose as it is no longer held together by roots and the topsoil becomes exposed. This allows for erosion by wind or water to occur. Wind can carry the soil into the air, creating dust storms capable of blocking sunlight. Water that runs off of the land can create gullies and carry sediment to nearby streams, affecting water quality and life within the streams. A gully formed 25 m wide by 95 m long and almost 10 m deep at a ranch in Texas.

The ranch owner notes,

“We’re still fighting erosion up here on all our land, is a constant battle, and we’re consistently losing creek bank after storms due to the severity of runoff upland of us…most creeks here hadn’t moved 5 feet [≈1.5 m] in decades, but now they’re moving 50–60 ft per year [≈17 m].”

The need for sustainable agricultural practices and improved land use planning with incentives for farmers to adopt soil or water conservation practices, is necessary. Conservation agriculture practices include no tillage or reduced soil disturbance, diversifying crop rotations, maintaining high levels of crop residue between plantings (corn stalks and stems left on the field between growing seasons), incorporating cover crops into crop rotations and integrating livestock into the cropping system. Soil is essential for nutrient cycling, biodiversity, and water regulation- not to mention, providing our world with food. Traditional farming practices cannot feed the world in a way that is both good for humans and the environment.





Benjamin L. Turner, Jay Fuhrer, Melissa Wuellner, Hector M. Menendez, Barry H. Dunn, Roger Gates. 2018. Scientific case studies in land-use driven soil erosion in the central United States: Why soil potential and risk concepts should be included in the principles of soil health. International Soil and Water Conservation Research. DOI.