Biological complexity: homeostasis (Introduction)

by David Turell , Tuesday, October 16, 2018, 19:04 (2020 days ago) @ David Turell

Another study tries to define the concept and find life obviously keeps in critical balance:

https://www.sciencedaily.com/releases/2018/10/181005111502.htm

"Biologists know a lot about how life works, but they are still figuring out the big questions of why life exists, why it takes various shapes and sizes, and how life is able to amazingly adapt to fill every nook and cranny on Earth. An interdisciplinary team of researchers has discovered that the answers to these questions may lie in the ability of life to find a middle ground, balancing between robustness and adaptability.

"To perform their study, they examined data from the Cell Collective database. This rich resource represents biological processes across life -- encapsulating a wide range of biological processes from humans to animals, plants, bacteria and viruses. The number of components in these networks ranged from five nodes to 321 nodes, encompassing 6500 different biological interactions.

"And these nodes include many of life's key building blocks -- genes and proteins that act as master switches controlling cell division, growth and death, and communication.

***

"'In a stable system, organisms will always come back to their original state," explains Daniels. "In an unstable system, the effect of a small change will grow and cause the whole system to behave differently."

"Through rigorous testing of the 67 networks, the team found that all of the networks shared a special property: They existed in between two extremes, neither too stable nor unstable.
As such, the team found that sensitivity, which is a measure of stability, was near a special point that biologists call "criticality," suggesting that the networks may be evolutionarily adapted to an optimal tradeoff between stability and instability.

"Previous studies have shown that a handful of biological systems, from neurons to ant colonies, lie in this middle ground of criticality and this new research expands the list of living systems in this state.

***

"'We still don't really understand what life is," says Walker, "and determining what quantitative properties, such as criticality, best distinguish life from non-life is an important step toward building that understanding at a fundamental level so that we may recognize life on other worlds or in our experiments on Earth, even if it looks very different than us."

"The findings also advance the field of quantitative biology by showing that, from the basic building blocks of life, scientists can identify a critical sensitivity that is common across a large swath of biology. And it promises to advance synthetic biology by allowing scientists to use life's building blocks to more accurately construct biochemical networks that are similar to living systems.

"'Each biological system has distinctive features, from its components and its size to its function and its interactions with the surrounding environment," explains co-author Hyunju Kim of the School of Earth and Space Exploration and the Beyond Center. "In this research, for the first time, we are able to make connections between the theoretical hypothesis on biological systems' universal tendency to retain the balance at the medium degree of stability and 67 biological models with various characteristics built on actual experiment data.'"

Comment: As far as I am concerned they are simply describing the obvious to any biologist, the fact that life must constantly exist in homeostasis.