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Tuesday, September 24, 2019

Book Reviewed: From Matter to Life: Information and Causality, Edited by Sara Imari Walker, Paul Davies and George Ellis

Maxwell’s Demon of a living cell

The cosmos is like a computer, and the information about matter and energy is processed in this computer to make physical reality. But the idea of “information” makes sense only to a conscious observer according to quantum physics. Classical/relativistic physics affirms that reality exists independent of conscious observers. In recent years, thermodynamics and the information dynamics have refined our understanding of physical reality.

In thermodynamics, entropy is related to a concrete process, but in quantum mechanics, this translates into the ability to measure and manipulate a system based on the information gathered by this measurement. A well-known example is Maxwell’s demon. Like life, Maxwell's imaginary demon seems to violate the second law of thermodynamics. But on careful examination it doesn't, so long as information is treated as a physical resource, an additional fuel.

In this book, physicist Paul Davies applies information as the key to understand life. Simple elements assemble to form molecules and then turn into life. But non-living matter also consists of the same atoms, then how do we explain this conversion? Non-life to life? Life is generally defined by its hallmarks: reproduction, harnessing energy, responding to stimuli, etc. But that doesn’t tell us what life is. We may know all about the complete genome of a mouse, but we don’t know what it is like to be a mouse!

The information flow in genetics is complex. This is illustrated in an experiment that chops the head and tail of a worm and applying electricity, which disrupts the information flow in regrowth. This results in a worm with a head at both ends, and they reproduce with those physical traits, even though they have the same DNA as the original one-headed worm!

Life is marked by a remarkable transformation in the organization of information facilitated by the operation of laws of physics. The cellular dynamics that includes complex biochemical reactions occurring in a concerted manner to support life. Genes, the molecular components of hereditary materials are read, decoded and translated into proteins. Then “life” uses these informational pathways for regulation and functioning of cells. Treating information as a physical quantity formulate "laws of life" that transcend life's physical substrate. This is where non-life is turning into life, but it is the information dynamics and not mere matter to matter transformation!

The authors take a cross-sectional view of quantum physics, chemistry, nanotechnology and information processing considering hardware (physics and chemistry) and software of life (biology). They don’t describe the nature of biological Maxwell Demon nor we can measure any of its physical attributes.

The first two chapters, Introduction; and the "Hard Problem" of Life by Sara Imari Walker and Paul Davies, Chapter 15. Biological Information, Causality, and Specificity - An Intimate Relationship by Karola Stotz and Paul E. Griffiths; Chapter 13. Living through Downward Causation - From Molecules to Ecosystems by Keith D. Farnsworth, George F. R. Ellis, and Luc Jaeger are interesting chapters. A college level physics, and biology would be helpful to appreciate this book.

Saturday, September 7, 2019

Book Reviewed: Plant Behaviour and Intelligence, by Anthony Trewavas

Plant Neurobiology

Adaptive information processing is a crucial evolutionary process in biological systems. Cells and tissues/organs in an organism function cooperatively as one complete biological machinery through which biological information flows. The author emphasizes the work of Nobel Laureate Barbara McClintock who expounded the idea that a biological cell integrates all information and responsible for cell-cell communication.

Although plants do not have a central nervous system or peripheral neurons, but they have intelligence. They perceive their surroundings and actively compete for limited resources and perform cost-benefit analysis. They take appropriate adaptive actions in response to environmental stimuli with their integrated signaling and communicative systems. Thus, plants adapt to their environment and evolved with different sensory and regulatory systems; they have complex adaptive behavior. This contrasts with animals which select their environment to find food and mate, but they also migrate with changing seasons. Since plants are fixed to a location, their adaptive behavior is different. For example, plants must synthesize their own food using basic components from soil and atmosphere using sunlight. An additional short-coming stems from the fact that half of plant behavior is in the root system that grows below the ground against gravity.

Adaptive differences between plants and animals is illustrated in some of their functions. For example, quantum mechanics has become an integral part of biochemical phenomenon such as photosynthesis in plants, and in avian migration and navigational systems. It is known for almost a century that almost all biological and biochemical interactions are known to follow the laws of classical physics with quantum mechanics operating indirectly through the electronic structures of the molecules. But now life is known to be lot more intricate since quantum physics operates directly in living beings. This offers the full benefits of its laws making life highly efficient and self-sustaining. Birds and insects (butterflies) migrate hundreds and thousands of miles using internal navigation systems that also operate on the laws of quantum physics. Evolved species like mammals seem to lack this highly efficient mechanisms illustrate the complexity of adaptation, natural selection, heritable characteristics, variation, mutation, reproduction and gene flow.

This is one of the better books I have read in this field that puts plant neurobiology in perspective without using the term “neurobiology.” The author addresses plant memory and learning mechanisms by focusing on cell-cell communication and plant behavior. Plants evolve just like animals, and experiments demonstrate that they have memory, intelligence and learning behavior.

Wednesday, September 4, 2019

Book Reviewed - The Hidden Life of Trees: What They Feel, How They Communicate―Discoveries from A Secret World by Peter Wohlleben

Tree Sociology; is this science or slobber?

Much of discussion refers to author’s experience with trees in Europe as a caretaker of a German forest. He is neither an experimental biologist nor did he investigate plant intelligence in any scientific rigor. He does not stay focused; and he doesn’t engage in any serious discussion that is relevant to plant behavior, but quickly drivel into ecology and environment. The book chapters are extremely short; in fact, there are 38 chapters which facilitates the author to deviate from the hub. There is no attempt from him to connect with readers with a scientific mind but rely upon their sensibilities. Environmentalism is a very appealing subject, and this book from a former forest ranger interests a casual reader.

I did not find anything unique in this book that stands out as a good scientific argument. The author’s efforts to tell us that trees have more than life; they have social behavior akin to animals is not convincing. How did this book become a bestseller? Because this is about tree sociology, ecology, environment, forestry and interconnectedness. The author provides scientific facts in bits and pieces to to convey his beliefs that trees have consciousness and mind.

Tuesday, September 3, 2019

Book Reviewed: The Revolutionary Genius of Plants: A New Understanding of Plant Intelligence and Behavior, by Stefano Mancuso

Do plants have memory and consciousness?

Plants do not have a central nervous system or neurons, but they have intelligence, because they perceive their surroundings; actively compete for the limited resources in the soil and atmosphere; they perform cost-benefit analysis; and take appropriate adaptive actions in response to environmental stimuli. plants have integrated signaling and communicative systems with complex adaptive behavior. Most animals choose their environment to find food, mate, and migrate with changing seasons, but plants adapt to their environment and hence have evolved different sensory and regulatory systems.

Author Mancuso argues strenuously that plants have consciousness and memory even though these terms are traditionally linked to brain. The term plant neurobiology is an intimidating word. He could have discussed numerous experimental evidences from literature that illustrate plants and animals behave similarly under some experimental conditions. For example, plants can be rendered unconscious by the same anesthetics that put animals out: drugs can make plants unresponsive like they are in a state of sleep; methyl jasmonate can induce a plant to produce defense substances such as phytoalexins (antimicrobial), nicotine or protease inhibitors. The protease inhibitors interfere with the insect digestive process and discourage the insect from eating the plant.

Instead of taking this traditional route of discussion to support his views, the book over-emphasizes the idea that plant neurobiology is real. But this idea is not new. Plant biologist Daniel Chamovitz wrote a book entitled, “What a Plant Knows: A Field Guide to the Senses” in 2012. The journal, Plant Signaling & Behavior was launched as a platform for fostering research in plant neurobiology. This is certainly an emerging field, but the author does not sound convincing in his presentation.