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91-566: Aaron, a wealthy amateur scholar, hires sexagenarian private investigator Howard, whom he meets at a chess club in Chicago to which they both belong, to investigate the gods Baal , Ashtoroth and Moloch , that were worshipped for centuries in Israel during a period of antiquity when the God of Abraham had fallen into disfavor. As Aaron says to Howard while proposing the task, referring to story of Exodus of

182-655: A Yale School of Public Health study. In a UNFPA report about ageing in the 21st century, it highlighted the need to "Develop a new rights-based culture of ageing and a change of mindset and societal attitudes towards ageing and older persons, from welfare recipients to active, contributing members of society". UNFPA said that this "requires, among others, working towards the development of international human rights instruments and their translation into national laws and regulations and affirmative measures that challenge age discrimination and recognise older people as autonomous subjects". Older people's music participation contributes to

273-409: A haploid chromosomal composition that is partially replicated, a condition known as merodiploidy . Prokaryotes lack mitochondria and chloroplasts . Instead, processes such as oxidative phosphorylation and photosynthesis take place across the prokaryotic cell membrane . However, prokaryotes do possess some internal structures, such as prokaryotic cytoskeletons . It has been suggested that

364-688: A paraphyletic group, just like dinosaurs without birds. Unlike the above assumption of a fundamental split between prokaryotes and eukaryotes, the most important difference between biota may be the division between Bacteria and the rest (Archaea and Eukaryota). For instance, DNA replication differs fundamentally between the Bacteria and Archaea (including that in eukaryotic nuclei), and it may not be homologous between these two groups. Moreover, ATP synthase , though common (homologous) in all organisms, differs greatly between bacteria (including eukaryotic organelles such as mitochondria and chloroplasts ) and

455-1088: A prokaryotic cytoskeleton that is more primitive than that of the eukaryotes. Besides homologues of actin and tubulin ( MreB and FtsZ ), the helically arranged building-block of the flagellum , flagellin , is one of the most significant cytoskeletal proteins of bacteria, as it provides structural backgrounds of chemotaxis , the basic cell physiological response of bacteria. At least some prokaryotes also contain intracellular structures that can be seen as primitive organelles. Membranous organelles (or intracellular membranes) are known in some groups of prokaryotes, such as vacuoles or membrane systems devoted to special metabolic properties, such as photosynthesis or chemolithotrophy . In addition, some species also contain carbohydrate-enclosed microcompartments, which have distinct physiological roles (e.g. carboxysomes or gas vacuoles). Most prokaryotes are between 1 μm and 10 μm, but they can vary in size from 0.2 μm ( Mycoplasma genitalium ) to 750 μm ( Thiomargarita namibiensis ). Prokaryotic cells have various shapes;

546-401: A taxon to be found nearby the then-unknown Asgard group). For example, histones which usually package DNA in eukaryotic nuclei, have also been found in several archaean groups, giving evidence for homology . This idea might clarify the mysterious predecessor of eukaryotic cells ( eucytes ) which engulfed an alphaproteobacterium forming the first eucyte ( LECA , l ast e ukaryotic c ommon

637-1198: A bacterium to bind, take up and recombine donor DNA into its own chromosome, it must first enter a special physiological state called competence . About 40 genes are required in Bacillus subtilis for the development of competence. The length of DNA transferred during B. subtilis transformation can be as much as a third to the whole chromosome. Transformation is a common mode of DNA transfer, and 67 prokaryotic species are thus far known to be naturally competent for transformation. Among archaea, Halobacterium volcanii forms cytoplasmic bridges between cells that appear to be used for transfer of DNA from one cell to another. Another archaeon, Sulfolobus solfataricus , transfers DNA between cells by direct contact. Frols et al. (2008) found that exposure of S. solfataricus to DNA damaging agents induces cellular aggregation, and suggested that cellular aggregation may enhance DNA transfer among cells to provide increased repair of damaged DNA via homologous recombination. While prokaryotes are considered strictly unicellular, most can form stable aggregate communities. When such communities are encased in

728-449: A biological timetable that might be a continuation of inherent mechanisms that regulate childhood growth and development. This regulation would depend on changes in gene expression that affect the systems responsible for maintenance, repair and defense responses. Factors causing errors or damage include internal and environmental events that induce cumulative deterioration in one or more organs . One 2013 review assessed ageing through

819-559: A broader sense, ageing can refer to single cells within an organism which have ceased dividing , or to the population of a species . In humans, ageing represents the accumulation of changes in a human being over time and can encompass physical, psychological, and social changes. Reaction time, for example, may slow with age, while memories and general knowledge typically increase. Ageing is associated with increased risk of cancer, Alzheimer's disease , diabetes , cardiovascular disease , increased mental health risks, and many more . Of

910-478: A common transition faced by the elderly, may have both positive and negative consequences. As cyborgs currently are on the rise some theorists argue there is a need to develop new definitions of ageing and for instance a bio-techno-social definition of ageing has been suggested. There is a current debate as to whether or not the pursuit of longevity and the postponement of senescence are cost-effective health care goals given finite health care resources. Because of

1001-399: A higher metabolic rate , a higher growth rate, and as a consequence, a shorter generation time than eukaryotes. There is increasing evidence that the roots of the eukaryotes are to be found in (or at least next to) the archaean Asgard group, perhaps Heimdallarchaeota (an idea which is a modern version of the 1984 eocyte hypothesis , eocytes being an old synonym for Thermoproteota ,

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1092-407: A large extent, is genetically based. For example, numerous perennial plants ranging from strawberries and potatoes to willow trees typically produce clones of themselves by vegetative reproduction and are thus potentially immortal, while annual plants such as wheat and watermelons die each year and reproduce by sexual reproduction. In 2008 it was discovered that inactivation of only two genes in

1183-409: A lower mortality rate compared to individuals who are not physically active. The majority of the benefits from exercise are achieved with around 3500 metabolic equivalent (MET) minutes per week. For example, climbing stairs 10 minutes, vacuuming 15 minutes, gardening 20 minutes, running 20 minutes, and walking or bicycling for 25 minutes on a daily basis would together achieve about 3000 MET minutes

1274-521: A ncestor) according to endosymbiotic theory . There might have been some additional support by viruses, called viral eukaryogenesis . The non-bacterial group comprising archaea and eukaryota was called Neomura by Thomas Cavalier-Smith in 2002. However, in a cladistic view, Eukaryota are Archaea in the same sense as birds are dinosaurs because they evolved from the Maniraptora dinosaur group. In contrast, archaea without eukaryota appear to be

1365-457: A new tissue or animal without ageing. Normal human cells however die after about 50 cell divisions in laboratory culture (the Hayflick Limit , discovered by Leonard Hayflick in 1961). A number of characteristic ageing symptoms are experienced by a majority, or by a significant proportion of humans during their lifetimes. Dementia becomes more common with age. About 3% of people between

1456-659: A nucleus. Both eukaryotes and prokaryotes contain large RNA / protein structures called ribosomes , which produce protein , but the ribosomes of prokaryotes are smaller than those of eukaryotes. Mitochondria and chloroplasts , two organelles found in many eukaryotic cells, contain ribosomes similar in size and makeup to those found in prokaryotes. This is one of many pieces of evidence that mitochondria and chloroplasts are descended from free-living bacteria. The endosymbiotic theory holds that early eukaryotic cells took in primitive prokaryotic cells by phagocytosis and adapted themselves to incorporate their structures, leading to

1547-438: A number of mental health issues as older adults deal with challenges such as the death of loved ones, retirement and loss of purpose, as well as their own health issues. Some warning signs are: changes in mood or energy, changes in sleep or eating habits, pain, sadness, unhealthy coping mechanisms such as smoking, suicidal ideations, and others. [1] Older adults are more prone to social isolation as well, which can further increase

1638-495: A safety net that contributes to the postponement of disability and prevention of impoverishment in old age". It has been argued that population ageing has undermined economic development and can lead to lower inflation because elderly individuals care especially strongly about the value of their pensions and savings. Evidence suggests that pensions, while making a difference to the well-being of older persons, also benefit entire families especially in times of crisis when there may be

1729-485: A shortage or loss of employment within households. A study by the Australian Government in 2003 estimated that "women between the ages of 65 and 74 years contribute A$ 16 billion per year in unpaid caregiving and voluntary work. Similarly, men in the same age group contributed A$ 10 billion per year." Due to increasing share of the elderly in the population, health care expenditures will continue to grow relative to

1820-690: A similar group of selfish individuals (see inclusive fitness and Hamilton's rule ). Should these instances of prokaryotic sociality prove to be the rule rather than the exception, it would have serious implications for the way we view prokaryotes in general, and the way we deal with them in medicine. Bacterial biofilms may be 100 times more resistant to antibiotics than free-living unicells and may be nearly impossible to remove from surfaces once they have colonized them. Other aspects of bacterial cooperation—such as bacterial conjugation and quorum-sensing-mediated pathogenicity , present additional challenges to researchers and medical professionals seeking to treat

1911-473: A single founder (in the way that animals and plants are founded by single cells), which presents a number of theoretical issues. Most explanations of co-operation and the evolution of multicellularity have focused on high relatedness between members of a group (or colony, or whole organism). If a copy of a gene is present in all members of a group, behaviors that promote cooperation between members may permit those members to have (on average) greater fitness than

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2002-430: A specific age for when an individual is allowed or obliged to do particular activities. These age specifications include voting age , drinking age , age of consent , age of majority , age of criminal responsibility , marriageable age , age of candidacy , and mandatory retirement age . Admission to a movie, for instance, may depend on age according to a motion picture rating system . A bus fare might be discounted for

2093-679: A stabilizing polymer matrix ("slime"), they may be called " biofilms ". Cells in biofilms often show distinct patterns of gene expression (phenotypic differentiation) in time and space. Also, as with multicellular eukaryotes, these changes in expression often appear to result from cell-to-cell signaling , a phenomenon known as quorum sensing . Biofilms may be highly heterogeneous and structurally complex and may attach to solid surfaces, or exist at liquid-air interfaces, or potentially even liquid-liquid interfaces. Bacterial biofilms are often made up of microcolonies (approximately dome-shaped masses of bacteria and matrix) separated by "voids" through which

2184-469: A week. Exercise has also been found to be an effective measure to treat declines in neuromuscular function due to age. A meta-analysis found that resistance training with elastic bands or kettlebells provided significant improvements to grip strength, gait speed, and skeletal muscle mass in patients with sarcopenia . Furthermore, another analysis found that the positive effects of resistance exercise on strength, muscle mass, and motor coordination reduce

2275-404: Is evidence on Mars of fossil or living prokaryotes. However, this possibility remains the subject of considerable debate and skepticism. The division between prokaryotes and eukaryotes is usually considered the most important distinction or difference among organisms. The distinction is that eukaryotic cells have a "true" nucleus containing their DNA , whereas prokaryotic cells do not have

2366-403: Is selected for in evolution. Traits that benefit early survival and reproduction will be selected for even if they contribute to an earlier death. Such a genetic effect is called the antagonistic pleiotropy effect when referring to a gene (pleiotropy signifying the gene has a double function – enabling reproduction at a young age but costing the organism life expectancy in old age) and is called

2457-588: Is a similar case for most Asian countries such as the Philippines, Thailand, Vietnam, Singapore, etc. Prokaryote A prokaryote ( / p r oʊ ˈ k ær i oʊ t , - ə t / ; less commonly spelled procaryote ) is a single-cell organism whose cell lacks a nucleus and other membrane -bound organelles . The word prokaryote comes from the Ancient Greek πρό ( pró ), meaning 'before', and κάρυον ( káruon ), meaning 'nut' or 'kernel'. In

2548-481: Is also evidence to suggest that exercise of any type may mitigate the degradation of the neuromuscular junction (NMJ) that occurs with age. Current evidence suggests that aerobic exercise causes the most hypertrophy of the NMJ, although resistance training is still somewhat effective. However, further evidence is necessary to identify optimal training protocols for NMJ function and to further understand how exercise affects

2639-459: Is another common visual disease that appears in older adults. Glaucoma is caused by damage to the optic nerve, causing vision loss. Glaucoma usually develops over time, but there are variations to glaucoma, and some have a sudden onset. There are a few procedures for glaucoma, but there is no cure or fix for the damage, once it has occurred. Prevention is the best measure in the case of glaucoma. In addition to physical symptoms, aging can also cause

2730-472: Is credited with lowering the risk of heart disease and early death. The major contributors to mortality risk reduction appear to be a higher consumption of vegetables, fish, fruits, nuts and monounsaturated fatty acids, such as by consuming olive oil. As of 2021, there is insufficient clinical evidence that calorie restriction or any dietary practice affects the process of ageing. People who participate in moderate to high levels of physical exercise have

2821-491: Is not mainly due to increasing demand from ageing populations, but rather has been driven by rising incomes, costly new medical technology, a shortage of health care workers and informational asymmetries between providers and patients. A number of health problems become more prevalent as people get older. These include mental health problems as well as physical health problems, especially dementia . It has been estimated that population ageing only explains 0.2 percentage points of

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2912-562: Is of particular concern, particularly in developed countries, while social protection and old-age pension coverage remain a challenge for developing countries, where a large proportion of the labour force is found in the informal sector." The global economic crisis has increased financial pressure to ensure economic security and access to health care in old age. To elevate this pressure "social protection floors must be implemented in order to guarantee income security and access to essential health and social services for all older persons and provide

3003-446: Is over 80 now in 33 countries. Ageing is a "global phenomenon", that is occurring fastest in developing countries, including those with large youth populations, and poses social and economic challenges to the work which can be overcome with "the right set of policies to equip individuals, families and societies to address these challenges and to reap its benefits". As life expectancy rises and birth rates decline in developed countries,

3094-625: Is the increase in the number and proportion of older people in society. Population ageing has three possible causes: migration, longer life expectancy (decreased death rate) and decreased birth rate. Ageing has a significant impact on society. Young people tend to have fewer legal privileges (if they are below the age of majority ), they are more likely to push for political and social change, to develop and adopt new technologies, and to need education. Older people have different requirements from society and government, and frequently have differing values as well, such as for property and pension rights. In

3185-465: The Old Testament : Nowhere does it say they don't exist ... What it says is they're false gods ... gods not to be trusted. Although Howard initially turns down the case, thinking Aaron is either crazy or a fool, Aaron is dogged, and increases his offer of reward until Howard eventually relents. However, Howard only agrees to work on the problem for one month to test whether any inroads can be made into

3276-480: The disposable soma effect when referring to an entire genetic programme (the organism diverting limited resources from maintenance to reproduction). The biological mechanisms which regulate lifespan probably evolved with the first multicellular organisms more than a billion years ago. However, even single-celled organisms such as yeast have been used as models in ageing, hence ageing has its biological roots much earlier than multi-cellularity. The Mediterranean diet

3367-533: The hard clam (known as quahog in New England) at 508 years, the Greenland shark at 400 years, various deep-sea tube worms at over 300 years, fish like the sturgeon and the rockfish , and the sea anemone and lobster . Such organisms are sometimes said to exhibit negligible senescence . The genetic aspect has also been demonstrated in studies of human centenarians . Life span, like other phenotypes ,

3458-481: The median age rises accordingly. According to the United Nations, this process is taking place in nearly every country in the world. A rising median age can have significant social and economic implications, as the workforce gets progressively older and the number of old workers and retirees grows relative to the number of young workers. Older people generally incur more health-related costs than do younger people in

3549-475: The two-empire system arising from the work of Édouard Chatton , prokaryotes were classified within the empire Prokaryota . However in the three-domain system , based upon molecular analysis , prokaryotes are divided into two domains : Bacteria (formerly Eubacteria) and Archaea (formerly Archaebacteria). Organisms with nuclei are placed in a third domain: Eukaryota . Prokaryotes evolved before eukaryotes, and lack nuclei, mitochondria , and most of

3640-594: The 21st century, one of the most significant population trends is ageing. Currently, over 11% of the world's current population are people aged 60 and older and the United Nations Population Fund (UNFPA) estimates that by 2050 that number will rise to approximately 22%. Ageing has occurred due to development which has enabled better nutrition, sanitation, health care, education and economic well-being. Consequently, fertility rates have continued to decline and life expectancy has risen. Life expectancy at birth

3731-479: The accumulated infirmities of old age, bioethicist Ezekiel Emanuel , opines that the pursuit of longevity via the compression of morbidity hypothesis is a "fantasy" and that human life is not worth living after age 75; longevity then should not be a goal of health care policy. This opinion has been contested by neurosurgeon and medical ethicist Miguel Faria , who states that life can be worthwhile during old age, and that longevity should be pursued in association with

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3822-490: The age of 80. This degeneration is caused by systemic changes in the circulation of waste products and by the growth of abnormal vessels around the retina. Other visual diseases that often appear with age are cataracts and glaucoma. A cataract occurs when the lens of the eye becomes cloudy, making vision blurry; it eventually causes blindness if untreated. They develop over time and are seen most often with those that are older. Cataracts can be treated through surgery. Glaucoma

3913-567: The ages of 65 and 74, 19% of those between 75 and 84, and nearly half of those over 85 years old have dementia. The spectrum ranges from mild cognitive impairment to the neurodegenerative diseases of Alzheimer's disease , cerebrovascular disease , Parkinson's disease and Lou Gehrig's disease . Furthermore, many types of memory decline with ageing , but not semantic memory or general knowledge such as vocabulary definitions. These typically increase or remain steady until late adulthood (see Ageing brain ). Intelligence declines with age, though

4004-512: The annual growth rate in medical spending of 4.3% since 1970. In addition, certain reforms to the Medicare system in the United States decreased elderly spending on home health care by 12.5% per year between 1996 and 2000. Beauty standards have evolved over time, and as scientific research in cosmeceuticals, cosmetic products seen to have medicinal benefits like anti-ageing creams, has increased,

4095-431: The annual plant Arabidopsis thaliana leads to its conversion into a potentially immortal perennial plant. The oldest animals known so far are 15,000-year-old Antarctic sponges , which can reproduce both sexually and clonally. Clonal immortality apart, there are certain species whose individual lifespans stand out among Earth's life-forms, including the bristlecone pine at 5062 years or 5067 years, invertebrates like

4186-608: The archaea/eukaryote nucleus group. The last common antecessor of all life (called LUCA , l ast u niversal c ommon a ncestor) should have possessed an early version of this protein complex. As ATP synthase is obligate membrane bound, this supports the assumption that LUCA was a cellular organism. The RNA world hypothesis might clarify this scenario, as LUCA might have been a ribocyte (also called ribocell) lacking DNA, but with an RNA genome built by ribosomes as primordial self-replicating entities . A Peptide-RNA world (also called RNP world) hypothesis has been proposed based on

4277-478: The associated diseases. Prokaryotes have diversified greatly throughout their long existence. The metabolism of prokaryotes is far more varied than that of eukaryotes, leading to many highly distinct prokaryotic types. For example, in addition to using photosynthesis or organic compounds for energy, as eukaryotes do, prokaryotes may obtain energy from inorganic compounds such as hydrogen sulfide . This enables prokaryotes to thrive in harsh environments as cold as

4368-433: The attainment of quality of life. Faria claims that postponement of senescence as well as happiness and wisdom can be attained in old age in a large proportion of those who lead healthy lifestyles and remain intellectually active. With age inevitable biological changes occur that increase the risk of illness and disability. UNFPA states that: "A life-cycle approach to health care – one that starts early, continues through

4459-450: The bacterial phylum Planctomycetota has a membrane around the nucleoid and contains other membrane-bound cellular structures. However, further investigation revealed that Planctomycetota cells are not compartmentalized or nucleated and, like other bacterial membrane systems, are interconnected. Prokaryotic cells are usually much smaller than eukaryotic cells. Therefore, prokaryotes have a larger surface-area-to-volume ratio , giving them

4550-587: The bacterium E. coli may split into distinguishable daughter cells, which opens the theoretical possibility of "age classes" among bacteria. Even within humans and other mortal species, there are cells with the potential for immortality: cancer cells which have lost the ability to die when maintained in a cell culture such as the HeLa cell line, and specific stem cells such as germ cells (producing ova and spermatozoa ). In artificial cloning , adult cells can be rejuvenated to embryonic status and then used to grow

4641-421: The biofilm—has led some to speculate that this may constitute a circulatory system and many researchers have started calling prokaryotic communities multicellular (for example ). Differential cell expression, collective behavior, signaling, programmed cell death , and (in some cases) discrete biological dispersal events all seem to point in this direction. However, these colonies are seldom if ever founded by

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4732-490: The bodies of other organisms, including humans. Prokaryotes have high populations in the soil - including the rhizosphere and rhizosheath . Soil prokaryotes are still heavily undercharacterized despite their easy proximity to humans and their tremendous economic importance to agriculture . In 1977, Carl Woese proposed dividing prokaryotes into the Bacteria and Archaea (originally Eubacteria and Archaebacteria) because of

4823-454: The current set of prokaryotic species may have evolved from more complex eukaryotic ancestors through a process of simplification. Others have argued that the three domains of life arose simultaneously, from a set of varied cells that formed a single gene pool. This controversy was summarized in 2005: There is no consensus among biologists concerning the position of the eukaryotes in the overall scheme of cell evolution. Current opinions on

4914-695: The economy in coming decades. This has been considered as a negative phenomenon and effective strategies like labour productivity enhancement should be considered to deal with negative consequences of ageing. In the field of sociology and mental health, ageing is seen in five different views: ageing as maturity , ageing as decline, ageing as a life-cycle event, ageing as generation, and ageing as survival. Positive correlates with ageing often include economics, employment, marriage, children, education, and sense of control, as well as many others. The social science of ageing includes disengagement theory, activity theory, selectivity theory, and continuity theory. Retirement,

5005-417: The emergence of the fungal/animal kingdoms approximately a billion years ago, and the evolution of seed-producing plants 320 million years ago. The sexual organism could henceforth pass on some of its genetic material to produce new individuals and could itself become disposable with respect to the survival of its species. This classic biological idea has however been perturbed recently by the discovery that

5096-530: The evolution and interrelationships of the three domains of life. The division between prokaryotes and eukaryotes reflects the existence of two very different levels of cellular organization; only eukaryotic cells have an enveloped nucleus that contains its chromosomal DNA , and other characteristic membrane-bound organelles including mitochondria. Distinctive types of prokaryotes include extremophiles and methanogens ; these are common in some extreme environments. The distinction between prokaryotes and eukaryotes

5187-480: The formation of the Earth's crust. Eukaryotes only appear in the fossil record later, and may have formed from endosymbiosis of multiple prokaryote ancestors. The oldest known fossil eukaryotes are about 1.7 billion years old. However, some genetic evidence suggests eukaryotes appeared as early as 3 billion years ago. While Earth is the only place in the universe where life is known to exist, some have suggested that there

5278-909: The four basic shapes of bacteria are: The archaeon Haloquadratum has flat square-shaped cells. Bacteria and archaea reproduce through asexual reproduction, usually by binary fission . Genetic exchange and recombination still occur, but this is a form of horizontal gene transfer and is not a replicative process, simply involving the transference of DNA between two cells, as in bacterial conjugation . DNA transfer between prokaryotic cells occurs in bacteria and archaea, although it has been mainly studied in bacteria. In bacteria, gene transfer occurs by three processes. These are (1) bacterial virus ( bacteriophage )-mediated transduction , (2) plasmid -mediated conjugation , and (3) natural transformation . Transduction of bacterial genes by bacteriophage appears to reflect an occasional error during intracellular assembly of virus particles, rather than an adaptation of

5369-482: The genus Hydra have a regenerative ability by which they avoid dying of old age. Early life forms on Earth, starting at least 3.7 billion years ago, were single-celled organisms. Such organisms ( Prokaryotes , Protozoans , algae ) multiply by fission into daughter cells; thus single celled organisms have been thought to not age and to be potentially immortal under favorable conditions. However, evidence has been reported that aging leading to death occurs in

5460-432: The host bacteria. The transfer of bacterial DNA is under the control of the bacteriophage's genes rather than bacterial genes. Conjugation in the well-studied E. coli system is controlled by plasmid genes, and is an adaptation for distributing copies of a plasmid from one bacterial host to another. Infrequently during this process, a plasmid may integrate into the host bacterial chromosome, and subsequently transfer part of

5551-537: The host bacterial DNA to another bacterium. Plasmid mediated transfer of host bacterial DNA (conjugation) also appears to be an accidental process rather than a bacterial adaptation. Natural bacterial transformation involves the transfer of DNA from one bacterium to another through the intervening medium. Unlike transduction and conjugation, transformation is clearly a bacterial adaptation for DNA transfer, because it depends on numerous bacterial gene products that specifically interact to perform this complex process. For

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5642-426: The idea that oligopeptides may have been built together with primordial nucleic acids at the same time, which also supports the concept of a ribocyte as LUCA. The feature of DNA as the material base of the genome might have then been adopted separately in bacteria and in archaea (and later eukaryote nuclei), presumably by help of some viruses (possibly retroviruses as they could reverse transcribe RNA to DNA). As

5733-408: The impact on health care demand. The large number of suggestions in the literature for specific interventions to cope with the expected increase in demand for long-term care in ageing societies can be organized under four headings: improve system performance; redesign service delivery; support informal caregivers; and shift demographic parameters. However, the annual growth in national health spending

5824-616: The industry has also expanded; the kinds of products they produce (such as serums and creams) have gradually gained popularity and become a part of many people's personal care routine. The increase in demand for cosmeceuticals has led scientists to find ingredients for these products in unorthodox places. For example, the secretion of cryptomphalus aspersa (or brown garden snail) has been found to have antioxidant properties, increase skin cell proliferation, and increase extracellular proteins such as collagen and fibronectin (important proteins for cell proliferation). Another substance used to prevent

5915-492: The internal processes (epigenetic maintenance such as DNA methylation ) inherently may cause ageing. Programmed ageing should not be confused with programmed cell death ( apoptosis ). Human beings and members of other species, especially animals, age and die. Fungi, too, can age. In contrast, many species can be considered potentially immortal : for example, bacteria fission to produce daughter cells, strawberry plants grow runners to produce clones of themselves, and animals in

6006-452: The lens of the damage theory, proposing nine metabolic "hallmarks" of ageing in various organisms but especially mammals: There are three main metabolic pathways which can influence the rate of ageing, discussed below: It is likely that most of these pathways affect ageing separately, because targeting them simultaneously leads to additive increases in lifespan. The rate of ageing varies substantially across different species, and this, to

6097-459: The maintenance of interpersonal relationships and promoting successful ageing. At the same time, older persons can make contributions to society including caregiving and volunteering. For example, "A study of Bolivian migrants who [had] moved to Spain found that 69% left their children at home, usually with grandparents. In rural China, grandparents care for 38% of children aged under five whose parents have gone to work in cities." Population ageing

6188-424: The major differences in the structure and genetics between the two groups of organisms. Archaea were originally thought to be extremophiles, living only in inhospitable conditions such as extremes of temperature , pH , and radiation but have since been found in all types of habitats . The resulting arrangement of Eukaryota (also called "Eucarya"), Bacteria, and Archaea is called the three-domain system , replacing

6279-788: The mechanisms that cause NMJ degradation. A meta-analysis showed that loneliness carries a higher mortality risk than smoking. Different cultures express age in different ways. The age of an adult human is commonly measured in whole years since the day of birth. (The most notable exception— East Asian age reckoning —is becoming less common, particularly in official contexts.) Arbitrary divisions set to mark periods of life may include juvenile (from infancy through childhood , preadolescence , and adolescence), early adulthood , middle adulthood , and late adulthood . Informal terms include " tweens ", "teenagers", "twentysomething", "thirtysomething", etc. as well as "denarian", "vicenarian", "tricenarian", "quadragenarian", etc. Most legal systems define

6370-406: The medium (e.g., water) may flow easily. The microcolonies may join together above the substratum to form a continuous layer, closing the network of channels separating microcolonies. This structural complexity—combined with observations that oxygen limitation (a ubiquitous challenge for anything growing in size beyond the scale of diffusion) is at least partially eased by movement of medium throughout

6461-571: The mitochondria and chloroplasts. The genome in a prokaryote is held within a DNA/protein complex in the cytosol called the nucleoid , which lacks a nuclear envelope . The complex contains a single, cyclic, double-stranded molecule of stable chromosomal DNA, in contrast to the multiple linear, compact, highly organized chromosomes found in eukaryotic cells. In addition, many important genes of prokaryotes are stored in separate circular DNA structures called plasmids . Like eukaryotes, prokaryotes may partially duplicate genetic material, and can have

6552-562: The much longer lives of even small mammals, such as the mouse (around 3 years). A model organism for the study of ageing is the nematode C. elegans – having a short lifespan of 2–3 weeks – enabling genetic manipulations or suppression of gene activity with RNA interference , and other factors. Most known mutations and RNA interference targets that extend lifespan were first discovered in C. elegans . The factors proposed to influence biological ageing fall into two main categories, programmed and error-related . Programmed factors follow

6643-403: The nucleus, that eukaryotes arose without endosymbiosis, and that eukaryotes arose through a symbiotic event entailing a simultaneous endosymbiotic origin of the flagellum and the nucleus, in addition to many other models, which have been reviewed and summarized elsewhere. The oldest known fossilized prokaryotes were laid down approximately 3.5 billion years ago, only about 1 billion years after

6734-408: The origin and position of eukaryotes span a broad spectrum including the views that eukaryotes arose first in evolution and that prokaryotes descend from them, that eukaryotes arose contemporaneously with eubacteria and archaebacteria and hence represent a primary line of descent of equal age and rank as the prokaryotes, that eukaryotes arose through a symbiotic event entailing an endosymbiotic origin of

6825-873: The other distinct organelles that characterize the eukaryotic cell. It was once thought that prokaryotic cellular components were unenclosed within the cytoplasm except for an outer cell membrane , but bacterial microcompartments , which are thought to be quasi-organelles enclosed in protein shells (such as the encapsulin protein cages ), have been discovered, along with other prokaryotic organelles . While being unicellular, some prokaryotes, such as cyanobacteria , may form colonies held together by biofilms , and large colonies can create multilayered microbial mats . Others, such as myxobacteria , have multicellular stages in their life cycles . Prokaryotes are asexual , reproducing via binary fission without any fusion of gametes , although horizontal gene transfer may take place. Molecular studies have provided insight into

6916-561: The peculiar case. It is indeed a problem — how to even begin investigating a trail that is centuries cold . Howard turns to a psychic for help, who using a Tarot card reading , sets Howard on a path which leads him to a young boy named Tim from Indiana , in whom the gods have taken an interest. Tim's father, who was in the midst of a mid-life crisis , has recently disappeared. Howard helps Tim in his quest to locate and determine what has become of his father. In their quest they are dogged by supernatural events that are eventually revealed as

7007-587: The physical manifestations of ageing is onobotulinumtoxinA, the toxin injected for Botox. In some cultures, old age is celebrated and honoured. In Korea, for example, a special party called hwangap is held to celebrate and congratulate an individual for turning 60 years old. In China, respect for elderly is often the basis for how a community is organized and has been at the foundation of Chinese culture and morality for thousands of years. Older people are respected for their wisdom and most important decisions have traditionally not been made without consulting them. This

7098-403: The rate varies depending on the type and may, in fact, remain steady throughout most of the human lifespan, dropping suddenly only as people near the end of their lives. Individual variations in the rate of cognitive decline may therefore be explained in terms of people having different lengths of life. There are changes to the brain: after 20 years of age, there is a 10% reduction each decade in

7189-469: The reproductive years and lasts into old age – is essential for the physical and emotional well-being of older persons, and, indeed, all people. Public policies and programmes should additionally address the needs of older impoverished people who cannot afford health care." Many societies in Western Europe and Japan have ageing populations. While the effects on society are complex, there is a concern about

7280-446: The risk for physical and mental conditions such as anxiety, depression, and cognitive decline. [2] A distinction can be made between "proximal ageing" (age-based effects that come about because of factors in the recent past) and "distal ageing" (age-based differences that can be traced to a cause in a person's early life, such as childhood poliomyelitis ). Ageing is among the greatest known risk factors for most human diseases . Of

7371-602: The risk of falls in the elderly, which is a key factor for living a longer and healthier life. In terms of programming, there is no one-size-fits-all approach. General recommendations for improvements to gait speed, strength, and muscle size for reduced fall risk are resistance training programs with two to three 40-60 minute workouts per week, consisting of 1-2 sets of 5-8 repetitions of 2-3 different exercises for each major muscle group, but individual considerations must be taken due to differences in health status, motivation, and accessibility to exercise facilities. There

7462-401: The roughly 150,000 people who die each day across the globe, about two-thirds die from age-related causes. Certain lifestyle choices and socioeconomic conditions have been linked to ageing. Current ageing theories are assigned to the damage concept, whereby the accumulation of damage (such as DNA oxidation ) may cause biological systems to fail, or to the programmed ageing concept, whereby

7553-421: The roughly 150,000 people who die each day across the globe, about two-thirds--100,000 per day--die from age-related causes . In industrialized nations, the proportion is higher, reaching 90%. In the 21st century, researchers are only beginning to investigate the biological basis of ageing even in relatively simple and short-lived organisms, such as yeast . Little is known of mammalian ageing, in part due to

7644-405: The single-cell bacterium Escherichia coli , an organism that reproduces by morphologically symmetrical division. Evidence of aging has also been reported for the bacterium Caulobacter crescintus . and the single cell yeast Saccharomyces cerevisiae . Ageing and mortality of the individual organism became more evident with the evolution of eukaryotic sexual reproduction , which occurred with

7735-427: The snow surface of Antarctica , studied in cryobiology , or as hot as undersea hydrothermal vents and land-based hot springs . Prokaryotes live in nearly all environments on Earth. Some archaea and bacteria are extremophiles , thriving in harsh conditions, such as high temperatures ( thermophiles ) or high salinity ( halophiles ). Many archaea grow as plankton in the oceans. Symbiotic prokaryotes live in or on

7826-467: The total length of the brain's myelinated axons . Age can result in visual impairment , whereby non-verbal communication is reduced, which can lead to isolation and possible depression. Older adults, however, may not experience depression as much as younger adults, and were paradoxically found to have improved mood, despite declining physical health. Macular degeneration causes vision loss and increases with age, affecting nearly 12% of those above

7917-426: The traditional two-empire system . According to the phylogenetic analysis of Hug (2016), the relationships could be the following: A widespread current model of the evolution of the first living organisms is that these were some form of prokaryotes, which may have evolved out of protocells , while the eukaryotes evolved later in the history of life. Some authors have questioned this conclusion, arguing that

8008-656: The workings of the gods who may be "false," but who are, nevertheless, real. This article about a thriller novel of the 2000s is a stub . You can help Misplaced Pages by expanding it . See guidelines for writing about novels . Further suggestions might be found on the article's talk page . Sexagenarian Ageing (or aging in American English ) is the process of becoming older . The term refers mainly to humans , many other animals , and fungi, whereas for example, bacteria, perennial plants and some simple animals are potentially biologically immortal . In

8099-720: The workplace and can also cost more in worker's compensation and pension liabilities. In most developed countries an older workforce is somewhat inevitable. In the United States for instance, the Bureau of Labor Statistics estimates that one in four American workers will be 55 or older by 2020. Among the most urgent concerns of older persons worldwide is income security. This poses challenges for governments with ageing populations to ensure investments in pension systems continues to provide economic independence and reduce poverty in old age. These challenges vary for developing and developed countries. UNFPA stated that, "Sustainability of these systems

8190-410: The young or old. Each nation, government, and non-governmental organization has different ways of classifying age. In other words, chronological ageing may be distinguished from "social ageing" (cultural age-expectations of how people should act as they grow older) and "biological ageing" (an organism's physical state as it ages). Ageism cost the United States $ 63 billion in one year according to

8281-520: Was firmly established by the microbiologists Roger Stanier and C. B. van Niel in their 1962 paper The concept of a bacterium (though spelled procaryote and eucaryote there). That paper cites Édouard Chatton 's 1937 book Titres et Travaux Scientifiques for using those terms and recognizing the distinction. One reason for this classification was so that what was then often called blue-green algae (now called cyanobacteria ) would not be classified as plants but grouped with bacteria. Prokaryotes have

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