Читать книгу Natural Environments and Human Health - Alan W Ewert - Страница 17

The evolution of the human species was made possible by the evolution of plants, especially trees, which process sunlight into energy through photosynthesis and release oxygen. Before the abundance of oxygen released by photosynthetic plants the Earth’s atmosphere was anaerobic and humans would not have evolved in the anaerobic environment. The oxygen-rich atmosphere formed the ozone layer, thus blocking ultraviolet solar radiation, and enabling more complex, oxygen-dependent forms of life, including humans, to evolve. The effect of this co-evolution, an absolute necessity for survival, continues today in terms of humans needing to breathe oxygen that plants make.

The results of co-evolution can be seen in many relationships in nature and this connection ties human health to the health of the natural environment. Humans eat plants which convert inorganic compounds to organic compounds (Pollan, 2002). Plants provide people with essential nutrients and human activity disperses plant seeds. Human guts also host intestinal microbes. For the past 5 years the National Institutes of Healthsponsored Microbiome Project has studied the bacteria, fungi, one-celled archaea, and viruses that live within the human digestive system. The conclusions were that humans can be considered a superorganism because of the extent and complexity of intestinal microbial life found. Microbes outnumber human cells at least ten to one and perform essential digestive and immune system functions. This relationship between humans and digestive tract microbiota mirrors examples of mutualistic evolution found at the global ecological system levels. These findings have implications for the healthcare and nutrition fields, and highlight the importance of human consumption of certain plants to promote growth of intestinal organisms that help human digestion and promote health.

Similarly, scientists have discovered the essential role of microbiota in plant health, a commensal relationship developed over 400 million years. Microbiota digest nutrients and protect plants from pathogens in a symbiotic relationship with fungi that creates mycorrhizae at plant roots. Discovery of the disruption and misunderstanding of the ecological role microbiota play in human gut and soil systems has caused some people to speculate a relationship between the loss of the organisms and the increase in immune system diseases in humans. Arden Andersen (2004), soil scientist and physician, claims that human health, gut microbiota, and soil health are directly correlated and have evolved concurrently. This evolutionary connection ties human health to the health of the natural environment.

Another connection humans share with nature is similarities in aspects of our response evolution. As one example, Sarah Earp, undergraduate music and neuroscience major, and Donna Maney, a neuroscientist at Emory University, report similar neural responses and pathways activated for birds and humans when listening to music, possibly demonstrating similar evolution of emotional responses to music and bird songs (Earp and Maney, 2012). They found that both music and bird song elicit responses in interconnected regions of human and bird brains thought to regulate emotion. The response of the mesolimbic reward system indicates the same neuroaffective mechanisms (meaning the way our emotions are tapped) in the bird and human listeners; namely, that some music or song results in dopamine release for birds and humans, and certain other music or song results in the activation of the amygdala or fear. This discovery may demonstrate that music shares many similar social functions in humans and in birds such as facilitating social contact, reducing conflict, helping to maintain personal attachments, and communicating emotional states (Koelsch, 2010). This study gives credence to the argument that humans, as well as other species, interact emotionally with their environment, including the natural environment.

Plants, like humans, have been shown to respond to music and emotions. Peter Tompkins and Christopher Bird discuss this phenomenon in The Secret Life of Plants (Tompkins and Bird, 1974) and Cleve Backster, past Interrogation Specialist for the Central Intelligence Agency, has presented his work with polygraph instruments and plants demonstrating emotions or reactions at the Institute of Noetic Sciences and the Institute for Transpersonal Psychology in Palo Alto, California. Backster (2003) reported that plants communicate with humans on an energetic or intuitive plane, demonstrating connection. He measured stress increases in plants in relationship to the stress of their human caretakers thousands of miles away. Backster found the connection to humans’ emotions still strong even if the plants were in lead containers, e.g. as human stress increased plant stress also increased.

Many animals seem to be aware of environmental changes before humans. Aware humans piggyback on the animals’ reactions by using their abilities in sensing and noticing the physical and biological signs for dangerous or other situations. For example, birds becoming noisy or quiet can signal predators. Rupert Sheldrake (2005) wrote about the many animals that survived the 2004 tsunami in Southeast Asia. He noted that in the 1970s authorities in earthquake-prone areas in China relied on cues from animals in order to evacuate towns. More research is needed in this area; although in a retrospective research project Marapana et al. (2012) found compelling evidence that animals that were not caged or tied were mostly able to escape from the 2004 tsunami. In the Yala National Park in Sri Lanka, no animal deaths were reported, even though it is on the coast.

These previous examples show the evolutionary connections between humans and other elements of the natural world. We need the microbes in our gut to survive and plants need the microbes in the soil to survive precisely because we have evolved together. In some cases co-evolution created mutualistic relationships, connecting humans to natural elements, and prompting the web of life theory that in fact all life is one living system. Other examples, such as human response to music being similar to bird response, show some of the similarities in our evolutionary development with other animals. A final aspect of co-evolution is the mapping of biodiversity and linguistic diversity. Skutnabb-Kangas et al. (2003) mapped approximately 7000 languages and found that high areas of biodiversity predicted high areas of linguistic diversity.