A Medley of Potpourri

Saturday, January 18, 2025

Wildlife conservation

From Wikipedia, the free encyclopedia
https://en.wikipedia.org/wiki/Wildlife_conservation

Wildlife conservation refers to the practice of protecting wild species and their habitats in order to maintain healthy wildlife species or populations and to restore, protect or enhance natural ecosystems. Major threats to wildlife include habitat destruction, degradation, fragmentation, overexploitation, poaching, pollution, climate change, and the illegal wildlife trade. The IUCN estimates that 42,100 species of the ones assessed are at risk for extinction. Expanding to all existing species, a 2019 UN report on biodiversity put this estimate even higher at a million species. It is also being acknowledged that an increasing number of ecosystems on Earth containing endangered species are disappearing. To address these issues, there have been both national and international governmental efforts to preserve Earth's wildlife. Prominent conservation agreements include the 1973 Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) and the 1992 Convention on Biological Diversity (CBD). There are also numerous nongovernmental organizations (NGO's) dedicated to conservation such as the Nature Conservancy, World Wildlife Fund, and Conservation International.

Threats to wildlife

Habitat destruction

Habitat destruction decreases the number of places where wildlife can live in. Habitat fragmentation breaks up a continuous tract of habitat, often dividing large wildlife populations into several smaller ones. Human-caused habitat loss and fragmentation are primary drivers of species declines and extinctions. Key examples of human-induced habitat loss include deforestation, agricultural expansion, and urbanization. Habitat destruction and fragmentation can increase the vulnerability of wildlife populations by reducing the space and resources available to them and by increasing the likelihood of conflict with humans. Moreover, destruction and fragmentation create smaller habitats. Smaller habitats support smaller populations, and smaller populations are more likely to go extinct. The COVID-19 pandemic has caused a significant shift in human behavior, resulting in mandatory and voluntary limitations on movement. As a result, people have started utilizing green spaces more frequently, which were previously habitats for wildlife. Unfortunately, this increased human activity has caused destruction to the natural habitat of various species.

Deforestation

Deforestation is the clearing and cutting down forests on purpose. Deforestation is a cause of human-induced habitat action destruction, by cutting down habitats of different species in the process of removing trees. Deforestation is often done for several reasons, often for either agricultural purposes or for logging, which is the obtainment of timber and wood for use in construction or fuel. Deforestation causes many threats to wildlife as it not only causes habitat destruction for the many animals that survive in forests, as more than 80% of the world's species live in forests but also leads to further climate change. Deforestation is a main concern in the tropical forests of the world. Tropical forests, like the Amazon, are home to the most biodiversity out of any other biome, making deforestation there an even more prevalent issue, especially in populated areas, as in these areas deforestation leads to habitat destruction and the endangerment of many species in one area. Some policies have been enacted to attempt to stop deforestation in different parts of the world, like the Wilderness Act of 1964 which designated specific areas wilderness to be protected.

Overexploitation

Overexploitation is the harvesting of animals and plants at a rate that's faster than the species' ability to recover. While often associated with Overfishing, overexploitation can apply to many groups including mammals, birds, amphibians, reptiles, and plants. The danger of overexploitation is that if too many of a species offspring are taken, then the species may not recover. For example, overfishing of top marine predatory fish like tuna and salmon over the past century has led to a decline in fish sizes as well as fish numbers.

Poaching

Poaching for illegal wildlife trading is a major threat to certain species, particularly endangered ones whose status makes them economically valuable. Such species include many large mammals like African elephants, tigers, and rhinoceros (traded for their tusks, skins, and horns respectively).Less well-known targets of poaching include the harvest of protected plants and animals for souvenirs, food, skins, pets, and more. Poaching causes already small populations to decline even further as hunters tend to target threatened and endangered species because of their rarity and large profits.

Ocean Acidification

As carbon dioxide levels increase concentration in the atmosphere, they increase in the ocean as well. Typically, the ocean will absorb carbon from the atmosphere, where it can be sequestered in the deep ocean and sea floor; this is a process called the biological pump. Increased carbon dioxide emissions and increased stratification (which slows the biological pump) decrease the ocean pH, making it more acidic. Calcifying organisms such as coral are especially susceptible to decreased pH, resulting in mass bleaching events, inevitably destroying a habitat for many of coral's diverse inhabitants. Research (conducted through methods such as coral fossils and ancient ice core carbon analysis) suggests ocean acidification has occurred in the geological past (more likely at a slower pace), and correlate with past extinction events.

Culling

Culling is the deliberate and selective killing of wildlife by governments for various purposes. An example of this is shark culling, in which "shark control" programs in Queensland and New South Wales (in Australia) have killed thousands of sharks, as well as turtles, dolphins, whales, and other marine life. The Queensland "shark control" program alone has killed about 50,000 sharks — it has also killed more than 84,000 marine animals. There are also examples of population culling in the United States, such as bison in Montana and swans, geese, and deer in New York and other places.

Pollution

A wide range of pollutants negatively impact wildlife health. For some pollutants, simple exposure is enough to do damage (e.g. pesticides). For others, its through inhaling (e.g. air pollutants) or ingesting it (e.g. toxic metals). Pollutants affect different species in different ways so a pollutant that is bad for one might not affect another.

Air pollutants: Most air pollutants come from burning fossil fuels and industrial emissions. These have direct and indirect effects on the health of wildlife and their ecosystems. For example, high levels of sulfur oxides (SO_x) can damage plants and stunt their growth. Sulfur oxides also contribute to acid rain, harming both terrestrial and aquatic ecosystems. Other air pollutants like smog, ground-level ozone, and particulate matter decrease air quality.
Heavy metals: Heavy metals like arsenic, lead, and mercury naturally occur at low levels in the environment, but when ingested in high doses, can cause organ damage and cancer. How toxic they are depends on the exact metal, how much was ingested, and the animal that ingested it. Human activities such as mining, smelting, burning fossil fuels, and various industrial processes have contributed to the rise in heavy metal levels in the environment.
Toxic chemicals: There are many sources of toxic chemical pollution including industrial wastewater, oil spills, and pesticides. There's a wide range of toxic chemicals so there's also a wide range of negative health effects. For example, synthetic pesticides and certain industrial chemicals are persistent organic pollutants. These pollutants are long-lived and can cause cancer, reproductive disorders, immune system problems, and nervous system problems.

Climate change

Humans are responsible for present-day climate change currently changing Earth's environmental conditions. It is related to some of the aforementioned threats to wildlife like habitat destruction and pollution. Rising temperatures, melting ice sheets, changes in precipitation patterns, severe droughts, more frequent heat waves, storm intensification, ocean acidification, and rising sea levels are some of the effects of climate change. Phenomena like droughts, wildfires, heatwaves, intense storms, ocean acidification, and rising sea levels, directly lead to habitat destruction. For example, longer dry seasons, warmer springs, and dry soil has been observed to increase the length of wildfire season in forests, shrublands and grasslands. Increased severity and longevity of wildfires can completely wipe out entire ecosystems, causing them to take decades to fully recover. Wildfires are a prime example of the direct negative effect climate change has on wildlife and ecosystems. Meanwhile, a warming climate, fluctuating precipitation, and changing weather patterns will impact species ranges. Overall, the effects of climate change increase stress on ecosystems, and species unable to cope with the rapidly changing conditions will go extinct. While modern climate change is caused by humans, past climate change events occurred naturally and have led to extinctions.

Illegal Wildlife Trade

The illegal wildlife trade is the illegal trading of plants and wildlife. This illegal trading is worth an estimate of 7-23 billion and an annual trade of around 100 million plants and animals. In 2021 it was found that this trade has caused a 60% decline in species abundance, and 80% for endangered species.

This trade can be devastating to both humans and animals. It has the capacity to spread zoonotic diseases to humans, as well as contribute to local extinction. The pathogens to humans may be spread through small animal vectors like ticks, or through ingestion of food and water. Extinction can be caused due to non-native species being introduced that become invasive. An example of how this may happen is through by-catch.These new species will outcompete the native species and take over, therefore causing the local or global extinction of a species.

Due to the fittest animals in the species being hunted or poached, the less fit organisms will mate, causing less fitness in the generations to come. In addition to species fitness being lowered and therefore endangering species, the illegal wildlife trade has ecological costs. Sex-ratio balances may be tipped or reproduction rates are slowed, which can be detrimental to vulnerable species. The recovery of these populations may take longer due to the reproduction rates being slower.

The wildlife trade also causes issues for natural resources that people use in their everyday lives. Ecotourism is how some people bring in money to their homes, and with depleting the wildlife, this may be a factor in taking away jobs.

Illegal wildlife trade has also become normalized through various social media outlets. There are TikTok accounts that have gone viral for their depiction of exotic pets, such as various monkey and bird species. These accounts show a cute and fun side of owning exotic pets, therefore indirectly encouraging illegal wildlife trade. On March 30, 2021, TikTik joined the Coalition to End Wildlife Trafficking Online. They, along with other big social media companies work to protect species from illegal, harmful trade online. Research has shown that machine learning can filter through social media posts to identify indications of illegal wildlife trade. This filtration system is able to search for keywords, pictures, and phrases that indicate illegal wildlife trade, and report it.

Species conservation

It is estimated that, because of human activities, current species extinction rates are about 1000 times greater than the background extinction rate (the 'normal' extinction rate that occurs without additional influence). According to the IUCN, out of all species assessed, over 42,100 are at risk of extinction and should be under conservation. Of these, 25% are mammals, 14% are birds, and 40% are amphibians. However, because not all species have been assessed, these numbers could be even higher. A 2019 UN report assessing global biodiversity extrapolated IUCN data to all species and estimated that 1 million species worldwide could face extinction. Conservation of a select species are often prioritized on several factors which include significant economic and ecological value, as well as desirability or attractiveness. Yet, because resources are limited, sometimes it is not possible to give all species that need conservation due consideration.

The species problem occurring in some cases due to natural hybridization, cryptic species, and natural evolution of species can be represented for species conservation by different approaches, such as multicriteria species approaches, subspecies, evolutionarily significant units, distinct population segments or species-population continuum.

Leatherback sea turtle

The leatherback sea turtle (Dermochelys coriacea) is the largest turtle in the world, is the only turtle without a hard shell, and is endangered. It is found throughout the central Pacific and Atlantic Oceans but several of its populations are in decline across the globe (though not all). The leatherback sea turtle faces numerous threats including being caught as bycatch, harvest of its eggs, loss of nesting habitats, and marine pollution. In the US where the leatherback is listed under the Endangered Species Act, measures to protect it include reducing bycatch captures through fishing gear modifications, monitoring and protecting its habitat (both nesting beaches and in the ocean), and reducing damage from marine pollution. There is currently an international effort to protect the leatherback sea turtle.

Habitat conservation

Habitat conservation is the practice of protecting a habitat in order to protect the species within it. This is sometimes preferable to focusing on a single species especially if the species in question has very specific habitat requirements or lives in a habitat with many other endangered species. The latter is often true of species living in biodiversity hotspots, which are areas of the world with an exceptionally high concentration of endemic species (species found nowhere else in the world). Many of these hotspots are in the tropics, mainly tropical forests like the Amazon. Habitat conservation is usually carried out by setting aside protected areas like national parks or nature reserves. Even when an area isn't made into a park or reserve, it can still be monitored and maintained.

Red-cockaded woodpecker

The red-cockaded woodpecker (Picoides borealis) is an endangered bird in the southeastern US. It only lives in longleaf pine savannas which are maintained by wildfires in mature pine forests. Today, it is a rare habitat (as fires have become rare and many pine forests have been cut down for agriculture) and is commonly found on land occupied by US military bases, where pine forests are kept for military training purposes and occasional bombings (also for training) set fires that maintain pine savannas. Woodpeckers live in tree cavities they excavate in the trunk. In an effort to increase woodpecker numbers, artificial cavities (essentially birdhouses planted within tree trunks) were installed to give woodpeckers a place to live. An active effort is made by the US military and workers to maintain this rare habitat used by red-cockaded woodpeckers.

Conservation genetics

Conservation genetics studies genetic phenomena that impact the conservation of a species. Most conservation efforts focus on managing population size, but conserving genetic diversity is typically a high priority as well. High genetic diversity increases survival because it means greater capacity to adapt to future environmental changes. Meanwhile, effects associated with low genetic diversity, such as inbreeding depression and loss of diversity from genetic drift, often decrease species survival by reducing the species' capacity to adapt or by increasing the frequency of genetic problems. Though not always the case, certain species are under threat because they have very low genetic diversity. As such, the best conservation action would be to restore their genetic diversity.

Florida panther

The Florida panther is a subspecies of cougar (specifically Puma concolor coryi) that resides in the state of Florida and is currently endangered. Historically, the Florida panther's range covered the entire southeastern US. In the early 1990s, only a single population with 20-25 individuals were left. The population had very low genetic diversity, was highly inbred, and suffered from several genetic issues including kinked tails, cardiac defects, and low fertility. In 1995, eight female Texas cougars were introduced to the Florida population. The goal was to increase genetic diversity by introducing genes from a different, unrelated puma population. By 2007, the Florida panther population had tripled and offspring between Florida and Texas individuals had higher fertility and less genetic problems. In 2015, the US Fish and Wildlife Service estimated there were 230 adult Florida panthers and in 2017, there were signs that the population's range was expanding within Florida.

Conservation methods

Wildlife Monitoring

Monitoring of wildlife populations is an important part of conservation because it allows managers to gather information about the status of threatened species and to measure the effectiveness of management strategies. Monitoring can be local, regional, or range-wide, and can include one or many distinct populations. Metrics commonly gathered during monitoring include population numbers, geographic distribution, and genetic diversity, although many other metrics may be used.

Monitoring methods can be categorized as either "direct" or "indirect". Direct methods rely on directly seeing or hearing the animals, whereas indirect methods rely on "signs" that indicate the animals are present. For terrestrial vertebrates, common direct monitoring methods include direct observation, mark-recapture, transects, and variable plot surveys. Indirect methods include track stations, fecal counts, food removal, open or closed burrow-opening counts, burrow counts, runaway counts, knockdown cards, snow tracks, or responses to audio calls.

For large, terrestrial vertebrates, a popular method is to use camera traps for population estimation along with mark-recapture techniques. This method has been used successfully with tigers, black bears and numerous other species. Trail cameras can be triggered remotely and automatically via sound, infrared sensors, etc. Computer vision-based animal individual re-identification methods have been developed to automate such sight-resight calculations. Mark-recapture methods are also used with genetic data from non-invasive hair or fecal samples. Such information can be analyzed independently or in conjunction with photographic methods to get a more complete picture of population viability.

When designing a wildlife monitoring strategy, it is important to minimize harm to the animal and implement the 3Rs principles (Replacement, Reduction, Refinement). In wildlife research, this can be done through the use of non-invasive methods, sharing samples and data with other research groups, or optimizing traps to prevent injuries.

Vaccine administration

Distributing vaccinations to wildlife who are particularly vulnerable is useful in conservation to prevent or decelerate extreme population declination in a species from disease and also decrease the risk of a zoonotic spillover to humans. A pathogen that has never once been exposed to a specific species' evolutionary pathway can have detrimental impacts on the population. In most cases, these risks escalate in conjunction to other anthropogenic stressors, such as climate change or habitat loss, that ultimately lead a population to extinction without human intervention. Methods of vaccination varies depending on both the extent and efficiency of limiting the transmission of disease, and can be applied orally, topically, intranasally (IN), or injected either subcutaneously (SC) or intramuscularly (IM). Conservation efforts regarding vaccinations often only serve the purpose of preventing disease related extinction. Rather than completely cleansing the population of the pathogen, infection rates are limited to a smaller percentage of the population.

Case study: Ethiopian Wolf

The Ethiopian Wolf (Canis simensis), a canid native to Ethiopia, is an endangered species with less than 440 wolves remaining in the wild. These wolves are primarily exposed to the rabies virus by domestic dogs and are facing extreme population declines, especially in the southern Ethiopia region of the Bale Mountains. To counter this, oral vaccinations are administered to these wolves within favorable bait that is widely distributed around their territories. The wolves consume the bait and with it ingest the vaccine, developing an immunity to rabies as antibodies are produced at significant levels. Wolves within these packs who did not ingest the vaccine will be protected by herd immunity as fewer wolves are exposed to the virus. With continued periodic vaccinations, conservationists will be able to spend more resources on further proactive efforts to help prevent their extinction.

Government involvement

In the US, the Endangered Species Act of 1973 was passed to protect US species deemed in danger of extinction. The concern at the time was that the country was losing species that were scientifically, culturally, and educationally important. In the same year, the Convention on International Trade in Endangered Species of Fauna and Flora (CITES) was passed as part of an international agreement to prevent the global trade of endangered wildlife. In 1980, the World Conservation Strategy was developed by the IUCN with help from the UN Environmental Programme, World Wildlife Fund, UN Food and Agricultural Organization, and UNESCO. Its purpose was to promote the conservation of living resources important to humans. In 1992, the Convention on Biological Diversity (CBD) was agreed on at the UN Conference on Environment and Development (often called the Rio Earth Summit) as an international accord to protect the Earth's biological resources and diversity.

According to the National Wildlife Federation, wildlife conservation in the US gets a majority of its funding through appropriations from the federal budget, annual federal and state grants, and financial efforts from programs such as the Conservation Reserve Program, Wetlands Reserve Program and Wildlife Habitat Incentives Program. A substantial amount of funding comes from the sale of hunting/fishing licenses, game tags, stamps, and excise taxes from the purchase of hunting equipment and ammunition.

The Endangered Species Act is a continuously updated list that remains up-to-date on species that are endangered or threatened. Along with the update of the list, the Endangered Species Act also seeks to implement actions to protect the species within its list. Furthermore, the Endangered Species Act also lists the species that the act has recovered. It is estimated that the act has prevented the extinction of about 291 species, like bald eagles and humpback whales, since its implementation through its different recovery plans and the protection that it provides for these threatened species.

Non-government involvement

In the late 1980s, as the public became dissatisfied with government environmental conservation efforts, people began supporting private sector conservation efforts which included several non-governmental organizations (NGOs) . Seeing this rise in support for NGOs, the U.S. Congress made amendments to the Foreign Assistance Act in 1979 and 1986 “earmarking U.S. Agency for International Development (USAID) funds for [biodiversity]”. From 1990 till now, environmental conservation NGOs have become increasingly more focused on the political and economic impact of USAID funds dispersed for preserving the environment and its natural resources. After the terrorist attacks on 9/11 and the start of former President Bush's War on Terror, maintaining and improving the quality of the environment and its natural resources became a “priority” to “prevent international tensions” according to the Legislation on Foreign Relations Through 2002 and section 117 of the 1961 Foreign Assistance Act.

Non-governmental organizations

Many NGOs exist to actively promote, or be involved with, wildlife conservation:

Friday, January 17, 2025

Idée fixe (psychology)

From Wikipedia, the free encyclopedia

Background

According to intellectual historian Jan E. Goldstein, the initial introduction of idée fixe as a medical term occurred around 1812 in connection with monomania. The French psychiatrist Jean-Étienne Dominique Esquirol considered an idée fixe – in other words an unhealthy fixation on a single object – to be the principal symptom of monomania. The term idée fixe had already seeped from psychiatric discourse into literary language before Hector Berlioz employed it in a musical context in his programmatic Symphonie fantastique (subtitled Episode in the Life of an Artist...) of 1830 to denote a recurring melodic theme that references the composer's own romantic obsession (or erotomania) with the actress Harriet Smithson. Especially around the 1820s and 1830s, the concepts of idée fixe and monomania became firmly associated with the Romantic movement in literature, and fixated protagonists feature in a variety of contemporary novels and plays, ranging from the serious to the almost humorous.

As originally employed in the nineteenth and early twentieth centuries, idée fixe described a more specific condition with respect to monomania (a term denoting a wider range of pathologies that did not stem only from a single fixation). A second difference is that the victim of idée fixe was understood to be unaware of the unreality of their frame of mind, while the victim of monomania might be aware. At that time, idée fixe was discussed as a form of neurosis or monomania. According to Goldstein, the original medical diagnosis of monomania "denoted an idée fixe, a single pathological preoccupation in an otherwise sound mind."

The idea of monomania as a diagnostic category was further developed by Esquirol in his work Des Malades Mentales (1839) and was coupled to the idée fixe by Wilhelm Griesinger (1845) who viewed "every single idée fixe [as] the expression of a deeply deranged psychic individuality and probably an indicator of an incipient form of mania".

The "pathologicalization" of political convictions was used to discredit political anarchists. The further historical evolution of idée fixe was much entangled with the introduction of psychologists into legal matters such as the insanity defense, and is found in a number of texts.

Development of the concept

The concept of idées fixes has been expanded and refined by Emil Kraepelin (1904), Carl Wernicke (1906), and Karl Jaspers (1963), evolving into a concept of overvalued ideas. An overvalued idea is a false or exaggerated and sustained belief that is maintained with much less than delusional intensity (i.e., the individual is able to acknowledge the possibility that the ideas may not be true).

Modern usage

In most contexts, idée fixe refers to an obsession or a passion one fixates on. However, the term also has a pathological dimension, denoting serious psychological issues. The pathology is what is denoted in psychology and law.

Idée fixe began as a parent category of obsession, and as a preoccupation of mind the idée fixe resembles today's obsessive–compulsive disorder (OCD). Although the afflicted person can think, reason and act like other people, they are unable to stop a particular train of thought or action. However, in obsessive–compulsive disorder, the person recognizes the absurdity of their obsession or compulsion, which may not be the case with an idée fixe (normally being a delusion). Today, the term idée fixe does not denote a specific disorder in psychology, and does not appear as a technical designation in the Diagnostic and Statistical Manual of Mental Disorders (DSM). It is still used as a descriptive term, appearing in dictionaries of psychology.

In literature

An example of an idée fixe is in Miguel de Cervantes' Don Quixote:

Don Quixote reveals his kinship to the most commonly encountered of Cervantes's character types: the head-in-clouds fantasist, obsessed by his idée fixe.
— Anthony J Close, Miguel de Cervantes, Don Quixote

Although Herman Melville's Captain Ahab may come to mind as another famous example of idée fixe, and it is sometimes referred to this way, more often Ahab's obsession is referred to as monomania (the more inclusive term), and Melville himself does that. It would seem from the description of Ahab's possession that idée fixe applies quite accurately, as the following description suggests:

"Not one jot of his great natural intellect had perished." ... "Yielding up all his thoughts and fancies to his one supreme purpose", Ahab has let his mind's guiding and directing power be usurped by the "sheer inveteracy" of a will driven by "one unachieved revengeful desire"
— Quotes from Moby-Dick, pp. 990, 1007, Thomas Cooley, The ivory leg in the ebony cabinet: madness, race, and gender in Victorian America

However, what makes monomania the better term is that "Captain Ahab ... has an inkling of his true state of mind: 'my means are sane, my motive and my object mad.'"

The words idée fixe also occur explicitly: for example, in Arthur Conan Doyle's Sherlock Holmes:

There is the condition which the modern French psychologists have called the 'idée fixe', which may be trifling in character, and accompanied by complete sanity in every other way. A man might form such an idée fixe... and under its influence be capable of any fantastic outrage.
— Arthur Conan Doyle, The return of Sherlock Holmes

and in Abraham B. Yehoshua's novel about the Mani family through six generations:

...I had begun to despair of his accursed idée fixe which devoured every other idée that it encountered...
— Abraham B. Yehoshua, Mr. Mani

and in the account of the war on terror by George Bush's counter-terrorism chief Richard A. Clarke:

Iraq was portrayed as the most dangerous thing in national security. It was an idée fixe, a rigid belief, received wisdom, a decision already made and one that no fact or event could derail.
— Richard A Clarke, Against All Enemies: Inside America's War on Terror

Legal implications

Possibly the best example of the role of idée fixe in an insanity defense today is its use in identifying paranoid personality disorder.

A frequent manifestation of ... paranoid personality is the presence of an overvalued idea ... a fixed idea (idée fixe) ... which might seem reasonable both to the patient and to other people. However, it comes to dominate completely the person's thinking and life. ... It is quite distinct phenomenologically from both delusion and obsessional idea.
— Femi Oyebode, The expression of disordered personality

Spandrel (biology)

From Wikipedia, the free encyclopedia

https://en.wikipedia.org/wiki/Spandrel_(biology)

In evolutionary biology, a spandrel is a phenotypic trait that is a byproduct of the evolution of some other characteristic, rather than a direct product of adaptive selection. Stephen Jay Gould and Richard Lewontin brought the term into biology in their 1979 paper "The Spandrels of San Marco and the Panglossian Paradigm: A Critique of the Adaptationist Programme". Adaptationism is a point of view that sees most organismal traits as adaptive products of natural selection. Gould and Lewontin sought to temper what they saw as adaptationist bias by promoting a more structuralist view of evolution.

The term "spandrel" originates from architecture, where it refers to the roughly triangular spaces between the top of an arch and the ceiling.

Etymology

The term was coined by paleontologist Stephen Jay Gould and population geneticist Richard Lewontin in their paper "The Spandrels of San Marco and the Panglossian Paradigm: A Critique of the Adaptationist Programme" (1979). Evolutionary biologist Günter P. Wagner called the paper "the most influential structuralist manifesto".

In their paper, Gould and Lewontin employed the analogy of spandrels in Renaissance architecture, such as the curved areas of masonry between arches supporting a dome that arise as a consequence of decisions about the shape of the arches and the base of the dome, rather than being designed for the artistic purposes for which they were often employed. The authors singled out properties like the necessary number of four spandrels and their specific three-dimensional shape. At the time, it was widely thought in the scientific community that everything an animal has developed that has a positive effect on that animal's fitness was due to natural selection or some adaptation. Gould and Lewontin proposed an alternative hypothesis: that due to adaptation and natural selection, byproducts are also formed. Because these byproducts of adaptations that had no real relative advantage to survival, they were termed spandrels. In the biological sense, a "spandrel" might result from a requirement inherent in the body plan of an organism, or as a byproduct of some other constraint on adaptive evolution.

In response to the position that spandrels are just small, unimportant byproducts, Gould and Lewontin argue that "we must not recognize that small means unimportant. Spandrels can be as prominent as primary adaptations". A main example used by Gould and Lewontin is the human brain. Many secondary processes and actions come in addition to the main functions of the human brain. These secondary processes and thoughts can eventually turn into an adaptation or provide a fitness advantage to humans. Just because something is a secondary trait or byproduct of an adaptation does not mean it has no use.

In 1982, Gould and Vrba introduced the term "exaptation" for characteristics that enhance fitness in their present role but were not built for that role by natural selection. Exaptations may be divided into two subcategories: pre-adaptations and spandrels. Spandrels are characteristics that did not originate by the direct action of natural selection and that were later co-opted for a current use. Gould saw the term to be optimally suited for evolutionary biology for "the concept of a nonadaptive architectural by-product of definite and necessary form – a structure of particular size and shape that then becomes available for later and secondary utility".

Criticism of the term

Gould and Lewontin's proposal generated a large literature of critique, which Gould characterised as being grounded in two ways. First, a terminological claim was offered that the "spandrels" of Basilica di San Marco were not spandrels at all, but rather were pendentives. Gould responded, "The term spandrel may be extended from its particular architectural use for two-dimensional byproducts to the generality of 'spaces left over', a definition that properly includes the San Marco pendentives."

Other critics, such as Daniel Dennett, further claimed (in Darwin's Dangerous Idea and elsewhere) that these pendentives are not merely architectural by-products as Gould and Lewontin supposed. Dennett argues that alternatives to pendentives, such as corbels or squinches, would have served equally well from an architectural standpoint, but pendentives were deliberately selected due to their aesthetic value. Critics such as H. Allen Orr argued that Lewontin and Gould's oversight in this regard illustrates their underestimation of the pervasiveness of adaptations found in nature.

Response to criticism

Gould responded that critics ignore that later selective value is a separate issue from origination as necessary consequences of structure; he summarised his use of the term 'spandrel' in 1997: "Evolutionary biology needs such an explicit term for features arising as byproducts, rather than adaptations, whatever their subsequent exaptive utility ... Causes of historical origin must always be separated from current utilities; their conflation has seriously hampered the evolutionary analysis of form in the history of life." Gould cites the masculinized genitalia of female hyenas and the brooding chamber of some snails as examples of evolutionary spandrels.

Gould (1991) outlines some considerations for grounds for assigning or denying a structure the status of spandrel, pointing first to the fact that a structure originating as a spandrel through primary exaptation may have been further crafted for its current utility by a suite of secondary adaptations, thus the grounds of how well crafted a structure is for a function cannot be used as grounds for assigning or denying spandrel status. The nature of the current utility of a structure also does not provide a basis for assigning or denying spandrel status, nor does he see the origin of a structure as having any relationship to the extent or vitality of a later co-opted role, but places importance on the later evolutionary meaning of a structure. This seems to imply that the design and secondary utilization of spandrels may feed back into the evolutionary process and thus determine major features of the entire structure. The grounds Gould does accept to have validity in assigning or denying a structure the status of spandrel are historical order and comparative anatomy. Historical order involves the use of historical evidence to determine which feature arose as a primary adaptation and which one appeared subsequently as a co-opted by-product. In the absence of historical evidence, inferences are drawn about the evolution of a structure through comparative anatomy. Evidence is obtained by comparing current examples of the structure in a cladistic context and by subsequently trying to determine a historical order from the distribution yielded by tabulation.

Examples of spandrels

Human chin

The human chin has been proposed as an example of a spandrel, since modern humans (Homo sapiens) are the only species with a chin, an anatomical feature with no known function. Alternatively however, it has been suggested that chins may be the result of selection, based on an analysis of the rate of chin evolution in the fossil record.

Language

There is disagreement among experts as to whether language is a spandrel.

Linguist Noam Chomsky and Gould himself have both argued that human language may have originated as a spandrel. Chomsky writes that the language faculty, and the property of discrete infinity or recursion that plays a central role in his theory of universal grammar (UG), may have evolved as a spandrel. In this view, Chomsky initially pointed to language being a result of increased brain size and increasing complexity, though he provides no definitive answers as to what factors may have led to the brain attaining the size and complexity of which discrete infinity is a consequence. Steven Pinker and Ray Jackendoff say Chomsky's case is unconvincing. Pinker contends that the language faculty is not a spandrel, but rather a result of natural selection.

Newmeyer (1998) instead views the lack of symmetry, irregularity and idiosyncrasy that universal grammar tolerates and the widely different principles of organization of its various sub-components and consequent wide variety of linking rules relating them as evidence that such design features do not qualify as an exaptation. He suggests that universal grammar cannot be derivative and autonomous at the same time, and that Chomsky wants language to be an epiphenomenon and an "organ" simultaneously, where an organ is defined as a product of a dedicated genetic blueprint. Rudolph Botha counters that Chomsky has offered his conception of the feature of recursion but not a theory of the evolution of the language faculty as a whole.

Music

There is disagreement among experts as to whether music is a spandrel.

Pinker has written that "As far as biological cause and effect are concerned, music is useless. It shows no signs of design for attaining a goal such as long life, grandchildren, or accurate perception and prediction of the world", and "I suspect that music is auditory cheesecake, an exquisite confection crafted to tickle the sensitive spots of at least six of our mental faculties." Dunbar found this conclusion odd, and stated that "it falls foul of what we might refer to as the Spandrel Fallacy: 'I haven't really had time to determine empirically whether or not something has a function, so I'll conclude that it can't possibly have one.'" Dunbar states that there are at least two potential roles of music in evolution: "One is its role in mating and mate choice, the other is its role in social bonding."

Cascadia subduction zone

From Wikipedia, the free encyclopedia
https://en.wikipedia.org/wiki/Cascadia_subduction_zone

Area of the Cascadia subduction zone (left) and a USGS scenario ShakeMap for a M9 event

The Cascadia subduction zone is a 960 km (600 mi) fault at a convergent plate boundary, about 100–200 km (70–100 mi) off the Pacific coast, that stretches from northern Vancouver Island in Canada to Northern California in the United States. It is capable of producing 9.0+ magnitude earthquakes and tsunamis that could reach 30 m (98 ft). The Oregon Department of Emergency Management estimates shaking would last 5–7 minutes along the coast, with strength and intensity decreasing further from the epicenter. It is a very long, sloping subduction zone where the Explorer, Juan de Fuca, and Gorda plates move to the east and slide below the much larger mostly continental North American plate. The zone varies in width and lies offshore beginning near Cape Mendocino, Northern California, passing through Oregon and Washington, and terminating at about Vancouver Island in British Columbia.

The Explorer, Juan de Fuca, and Gorda plates are some of the remnants of the vast ancient Farallon plate which is now mostly subducted under the North American plate. The North American plate itself is moving slowly in a generally southwest direction, sliding over the smaller plates as well as the huge oceanic Pacific plate (which is moving in a northwest direction) in other locations such as the San Andreas Fault in central and southern California.

Tectonic processes active in the Cascadia subduction zone region include accretion, subduction, deep earthquakes, and active volcanism of the Cascades. This volcanism has included such notable eruptions as Mount Mazama (Crater Lake) about 7,500 years ago, the Mount Meager massif (Bridge River Vent) about 2,350 years ago, and Mount St. Helens in 1980. Major cities affected by a disturbance in this subduction zone include Vancouver and Victoria, British Columbia; Seattle, Washington; and Portland, Oregon.

History

Tradition

There are no contemporaneous written records of the 1700 Cascadia earthquake. Orally transmitted legends from the Olympic Peninsula area tell of an epic battle between a thunderbird and a whale. In 2005, seismologist Ruth Ludwin set out to collect and analyze anecdotes from various First Nations groups. Reports from the Huu-ay-aht, Makah, Hoh, Quileute, Yurok, and Duwamish peoples referred to earthquakes and saltwater floods. This collection of data allowed the researchers to come up with an estimated date range for the event; the midpoint was in the year 1701.

Ghost forests

During low tide one day in March 1986, paleogeologist Brian Atwater dug along Neah Bay with a nejiri gama, a small hand hoe. Under a top layer of sand, he uncovered a distinct plant—arrowgrass—that had grown in a layer of marsh soil. This finding was evidence that the ground had suddenly sunk under sea level, causing saltwater to kill the vegetation. The event had happened so quickly that the top layer of sand sealed away the air, thus preserving centuries-old plants.

In 1987, Atwater mounted another expedition paddling up the Copalis River with Dr. David Yamaguchi, who was then studying the eruptions of Mount St. Helens. The pair happened upon a section of "ghost forest", so-called due to the dead, gray stumps left standing after a sudden inundation of salt water had killed them hundreds of years ago. Originally thought to have died slowly due to a gradual rise in sea level, closer inspection yielded a different story: the land plummeted up to two meters during an earthquake. Having initially tested spruce using tree-ring dating, they found that the stumps were too rotted to count all the outer rings. However, upon having examined those of the western red cedar and comparing them to the living specimens meters away from the banks, they were able to approximate their year of death. There were rings up until the year 1699, indicating that the incident had occurred shortly thereafter. Root samples confirmed their conclusion, narrowing the time frame to the winter of 1699 to 1700.

As with the arrowgrass site, the banks of the Copalis River are lined with a layer of marsh followed by a layer of sand. Jody Bourgeois and her team went on to demonstrate that the sand cover had originated with a tsunami surge rather than a storm surge.

In 1995, an international team led by Alan Nelson of the USGS further corroborated these findings with 85 new samples from the rest of the Pacific Northwest. All along British Columbia, Washington State, and Oregon, the coast had fallen due to a violent earthquake and been covered by sand from the subsequent tsunami.

A further ghost forest was identified by Gordon Jacoby, a dendrochronologist from Columbia University, 60 feet (18 m) underwater in Lake Washington. Unlike the other trees, these suffered from a landslide rather than a dip in the fault during a separate event around 900 CE.

Activity

In the 1960s, underground fractures were uncovered by oil companies in Puget Sound. These were believed to be inactive through the 1990s.

In the 1980s, geophysicists Tom Heaton and Hiroo Kanamori of Caltech compared the generally quiet Cascadia to more active subduction zones elsewhere in the Ring of Fire. They found similarities to faults in Chile, Alaska, and Japan's Nankai Trough, locations known for megathrust earthquakes, a conclusion that was met with skepticism from other geophysicists at the time.

Orphan tsunami

A 1996 study published by seismologist Kenji Satake supplemented the research by Atwater et al. with tsunami evidence across the Pacific. Japanese annals, which have recorded natural disasters since approximately 600 CE, had reports of a sixteen-foot tsunami that struck the coast of Honshu Island during the Genroku era. Since no earthquake had been observed to produce it, scholars dubbed it an "orphan tsunami". Translating the Japanese calendar, Satake found the incident had taken place around midnight of 27–28 January 1700, ten hours after the earthquake occurred. The original magnitude 9.0 earthquake in the Pacific Northwest had thus occurred around 9 pm Pacific Standard Time on 26 January 1700.

Geophysics

Structure of the Cascadia subduction zone

The Cascadia subduction zone is a 1,000 km (620 mi) long dipping fault that stretches from Northern Vancouver Island to Cape Mendocino in northern California. It separates the Juan de Fuca and North America plates. New Juan de Fuca plate is created offshore along the Juan de Fuca Ridge.

The Juan de Fuca plate moves toward, and eventually is pushed under the continent (North American plate). The zone separates the Juan de Fuca plate, Explorer plate, Gorda plate, and North American plate. Here, the oceanic crust of the Pacific Ocean has been sinking beneath the continent for about 200 million years, and currently does so at a rate of approximately 40 mm/yr.

At depths shallower than 30 km (19 mi) or so, the Cascadia zone is locked by friction while stress slowly builds up as the subduction forces act, until the fault's frictional strength is exceeded and the rocks slip past each other along the fault in a megathrust earthquake. Below 30 km (19 mi) the plate interface exhibits episodic tremor and slip.

The width of the Cascadia subduction zone varies along its length, depending on the angle of the subducted oceanic plate, which heats up as it is pushed deeper beneath the continent. As the edge of the plate sinks and becomes hotter and more molten, the subducting rock eventually loses the ability to store mechanical stress; earthquakes may result. On the Hyndman and Wang diagram (not shown, click on reference link below) the "locked" zone is storing up energy for an earthquake, and the "transition" zone, although somewhat plastic, could probably rupture.

The Cascadia subduction zone runs from triple junctions at its north and south ends. To the north, just below Haida Gwaii, it intersects the Queen Charlotte Fault and the Explorer Ridge. To the south, just off Cape Mendocino in California, it intersects the San Andreas Fault and the Mendocino fracture zone at the Mendocino triple junction.

Recent seismicity

Subduction zones experience various types of earthquakes (or seismicity); including slow earthquakes, megathrust earthquakes, interplate earthquakes, and intraplate earthquakes. Unlike other subduction zones on Earth, Cascadia currently experiences low levels of seismicity and has not generated a megathrust earthquake since January 26, 1700. Despite low levels of seismicity compared to other subduction zones, Cascadia hosts various types of earthquakes that are recorded by seismic and geodetic instruments, such as seismometers and GNSS receivers.

Tremor, a type of slow fault slip, occurs along almost the entire length of Cascadia at regular intervals of 13–16 months. Tremor occurs deeper on the subduction interface than the locked area where megathrust earthquakes occur. The depth of tremor along the subduction interface in Cascadia ranges from 28 km to 45 km, and the motion is so slow that it is not felt at the surface by people or animals, but it can be measured geodetically. The highest density of tremor activity in Cascadia occurs from northern Washington into southern Vancouver Island, and in northern California. Tremor in Cascadia is monitored by the Pacific Northwest Seismic Network's semi-automatic tremor detection system.

The majority of interplate earthquakes, or earthquakes that occur near the boundaries of tectonic plates, near the Cascadia subduction zone occur in the forearc of the overriding North American plate in Washington, west of the Cascade Volcanic Arc and east of where tremor occurs. These earthquakes are sometimes referred to as crustal earthquakes, and they are capable of causing significant damage due to their relatively shallow depths. A damaging magnitude 7 interplate earthquake occurred on the Seattle Fault around 900–930 CE that generated 3 meters of uplift and a 4-5 meter tsunami. A substantial number of forearc interplate earthquakes also occur in northern California. Much less interplate seismicity occurs in Oregon compared to Washington and northern California, although Oregon hosts more volcanic activity than its neighboring states.

Intraslab earthquakes, frequently associated with stresses within the subducting plate in convergent margins, occur most frequently in northern Cascadia along the west coast of Vancouver Island and in Puget Sound, and in southern Cascadia within the subducting Gorda plate, near the Mendocino triple junction offshore of northern California. The 1949 Olympia earthquake was a damaging magnitude 6.7 intraslab earthquake that occurred at 52 km depth and caused eight deaths. Another notable intraslab earthquake in the Puget Sound region was the magnitude 6.8 2001 Nisqually earthquake. Intraslab earthquakes in Cascadia occur in areas where the subducting plate has high curvature. Much of the seismicity that occurs off the coast of northern California is due to intraplate deformation within the Gorda plate. Similar to the distribution of interplate earthquakes in Cascadia, intraslab earthquakes are infrequent in Oregon, with its strongest earthquake since statehood being the 5.6 magnitude 1993 Scotts Mills earthquake, an oblique-slip quake.

Megathrust earthquakes

Earthquake effects

Megathrust earthquakes are the most powerful earthquakes known to occur, and can exceed magnitude 9.0, which releases 1,000 times more energy than magnitude 7.0 and 1 million times more energy than a magnitude 5.0. They occur when enough energy (stress) has accumulated in the "locked" zone of the fault to cause a rupture. The magnitude of a megathrust earthquake is proportional to length of the rupture along the fault. The Cascadia subduction zone, which forms the boundary between the Juan de Fuca and North American plates, is a very long sloping fault that stretches from mid-Vancouver Island to Northern California.

Because of the great length of the fault, the Cascadia subduction zone is capable of producing very large earthquakes if rupture occurs along its entire length. Thermal and deformation studies indicate that the region 60 kilometers (about 40 miles) downdip (east) of the deformation front (where plate deformation begins) is fully locked (the plates do not move past each other). Further downdip, there is a transition from fully locked to aseismic sliding.

In 1999, a group of Continuous Global Positioning System sites registered a brief reversal of motion of approximately 2 centimeters (0.8 inches) over a 50 kilometer by 300 kilometer (about 30 mile by 200 mile) area. The movement was the equivalent of a 6.7 magnitude earthquake. The motion did not trigger an earthquake and was only detectable as silent, non-earthquake seismic signatures.

In 2004, a study conducted by the Geological Society of America analyzed the potential for land subsidence along the Cascadia subduction zone. It postulated that several towns and cities on the west coast of Vancouver Island, such as Tofino and Ucluelet, are at risk for a sudden, earthquake initiated, 1–2 m subsidence.

San Andreas Fault connection

Studies of past earthquake traces on both the northern San Andreas Fault and the southern Cascadia subduction zone indicate a correlation in time which may be evidence that quakes on the Cascadia subduction zone may have triggered most of the major quakes on the northern San Andreas during at least the past 3,000 years or so. The evidence also shows the rupture direction going from north to south in each of these time-correlated events. The 1906 San Francisco earthquake seems to have been a major exception to this correlation, however, as it was not preceded by a major Cascadia quake.

Earthquake timing

Great earthquakes
estimated year		interval
2005 source	2003 source	(years)
About 9 p.m., January 26, 1700 (NS)		780
780–1190 CE	880–960 CE	210
690–730 CE	550–750 CE	330
350–420 CE	250–320 CE	910
660-440 BCE	610–450 BCE	400
980–890 BCE	910–780 BCE	250
1440–1340 BCE	1150–1220 BCE	unknown

The last known great earthquake in the northwest was the 1700 Cascadia earthquake, 324 years ago. Geological evidence indicates that great earthquakes (> magnitude 8.0) may have occurred sporadically at least seven times in the last 3,500 years, suggesting a return time of about 500 years. Seafloor core evidence indicates that there have been forty-one subduction zone earthquakes on the Cascadia subduction zone in the past 10,000 years, suggesting a general average earthquake recurrence interval of only 243 years. Of these 41, nineteen have produced a "full margin rupture", wherein the entire fault opens up. By comparison, similar subduction zones in the world usually have such earthquakes every 100 to 200 years; the longer interval here may indicate unusually large stress buildup and subsequent unusually large earthquake slip.

There is also evidence of accompanying tsunamis with every earthquake. One strong line of evidence for these earthquakes is convergent timings for fossil damage from tsunamis in the Pacific Northwest and historical Japanese records of tsunamis.

The next rupture of the Cascadia subduction zone is anticipated to be capable of causing widespread destruction throughout the Pacific Northwest.

Forecasts of the next major earthquake

Prior to the 1980s, scientists thought that the subduction zone did not generate earthquakes like other subduction zones around the world, but research by Brian Atwater and Kenji Satake tied together evidence of a large tsunami on the Washington coast with documentation of an orphan tsunami in Japan (a tsunami without an associated earthquake). The two pieces of the puzzle were linked, and they then realized that the subduction zone was more hazardous than previously suggested.

In 2009, some geologists predicted a 10% to 14% probability that the Cascadia subduction zone will produce an event of magnitude 9.0 or higher in the next 50 years. In 2010, studies suggested that the risk could be as high as 37% for earthquakes of magnitude 8.0 or higher.

Geologists and civil engineers have broadly determined that the Pacific Northwest region is not well prepared for such a colossal earthquake. The earthquake is expected to be similar to the 2011 Tōhoku earthquake and tsunami, because the rupture is expected to be as long as the 2004 Indian Ocean earthquake and tsunami. The resulting tsunami might reach heights of approximately 30 meters (100 ft). FEMA estimates some 13,000 fatalities from such an event, with another 27,000 injured, which would make it the deadliest natural disaster in American, and North American, history. FEMA further predicts that a million people will be displaced, with yet another 2.5 million requiring food and water. An estimated 1/3 of public safety workers will not respond to the disaster due to a collapse in infrastructure and a desire to ensure the safety of themselves and their loved ones. Other analyses predict that even a magnitude 6.7 earthquake in Seattle would result in 7,700 dead and injured, $33 billion in damage, 39,000 buildings severely damaged or destroyed, and 130 simultaneous fires.

Cascade Volcanic Arc

The Cascade Volcanic Arc is a continental volcanic arc that extends from northern California to the coastal peninsula of Alaska. The arc consists of a series of Quaternary age stratovolcanoes that grew on top of pre-existing geologic materials that ranged from Miocene volcanics to glacial ice. The Cascade Volcanic arc is located approximately 100 km inland from the coast, and forms a north-to-south chain of peaks that average over 3,000 m (10,000 ft) in elevation. The major peaks from south to north include:

Lassen Peak and Mount Shasta (California)
Crater Lake (Mazama), Three Sisters, Mount Jefferson, Mount Hood (Oregon)
Mount Adams, Mount St. Helens, Mount Rainier, Glacier Peak, Mount Baker (Washington)
Mount Garibaldi and Mount Meager massif (British Columbia)

The most active volcanoes in the chain include Mount St. Helens, Mount Baker, Lassen Peak, Mount Shasta, and Mount Hood. Mount St. Helens captured worldwide attention when it erupted catastrophically in 1980. St. Helens continues to rumble, albeit more quietly, emitting occasional steam plumes and experiencing small earthquakes, both signs of continuing magmatic activity.

Most of the volcanoes have a main, central vent from which the most recent eruptions have occurred. The peaks are composed of layers of solidified andesitic to dacitic magma, and the more siliceous (and explosive) rhyolite.

Volcanoes above the subduction zone

The volcanoes above the subduction zone include:

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