The Modulation of Lifespan by Natural Selection

Holliday, Robin

doi:10.1007/978-94-017-0283-6_2

Cited by 2 publications

(4 citation statements)

References 19 publications

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“…In this case, mortality is reduced, so that the individuals, on average, will survive for a longer period of time. Moreover, the females that live the longest will produce the most offspring, and genes that favour this trend will therefore be selected (Holliday 1996(Holliday , 2003. One consequence of this evolutionary change may be an increase in animal numbers, but then the food resources required would also have to increase.…”

Section: Natural Selection For Reduced Mortalitymentioning

confidence: 97%

“…A few years later Williams (1957) argued that there would be selection for pleiotropic mutations which increase survival in young animals, whilst decreasing it in old ones. The Medawar-Williams theories are really concerned with the modulation of longevity rather than the evolution of ageing, because organisms that do not age at all (such as some simple animals) are in a steady state, and therefore there can be no early-acting and late-acting genes (Holliday 2003).…”

Section: Introductionmentioning

confidence: 99%

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Ageing and the extinction of large animals

Holliday¹

2005

Biogerontology

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In the modulation of longevity by natural selection there is a trade-off between the investment of resources in the maintenance of the body, or soma, and the investment in reproduction. There is accumulating evidence that long-lived mammalian species have much more efficient maintenance than short-lived ones. It is also clear that short-lived ground-living mammalian species reproduce very much more quickly than larger long-lived species, and in all mammals there is an inverse relationship between maximum reproductive potential and maximum longevity. These features of life-history strategies very strongly support the disposable soma theory of the evolution of ageing. Slow development and large size are associated with delayed ageing. If the environment changes, for whatever reason, small rapidly breeding species are able to adapt and survive much more easily that large slow breeding species. This can explain the very well documented extinction of many large mammalian species during the Pleistocene. In an environment which remains constant for a long period of time, selection favours the evolution of larger species, but these are put at risk if the environment becomes less favorable. Fluctuating environments are more likely to promote the evolution of small short-lived species with high fecundity.

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Section: Natural Selection For Reduced Mortalitymentioning

confidence: 97%

Section: Introductionmentioning

confidence: 99%

Ageing and the extinction of large animals

Holliday¹

2005

Biogerontology

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“…With regard to life span, there have been two very different trends in mammalian evolution. 24 If the mortality increases, perhaps on account of a change in environment or the appearance of a new predator, then the population will decline. There will then be selection for earlier development and reproduction, with an increase in the number of offspring.…”

Section: The Modulation Of Aging By Natural Selectionmentioning

confidence: 99%

“…With regard to life span, there have been two very different trends in mammalian evolution 24 . If the mortality increases, perhaps on account of a change in environment or the appearance of a new predator, then the population will decline.…”

Section: The Modulation Of Aging By Natural Selectionmentioning

confidence: 99%

Aging is No Longer an Unsolved Problem in Biology

Holliday

2006

Annals of the New York Academy of Sciences

138

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For much of the 20th century, the accumulation of a considerable amount of information about the processes of aging did not reveal the underlying mechanisms. Toward the end of that century, the biological basis for aging became very much clearer. It became apparent that the best strategy for animals' survival was to develop to an adult, but not to invest resources in maintaining the body, or soma, indefinitely. In their natural environment, animals do not survive environmental hazards (predators, disease, starvation, and drought) to reach a long life span. There is thus a trade-off between the investment of resources in reproduction, and the survival time of the soma. At a stroke, this solves the problem of different rates of aging in different species, because those that develop and reproduce fast also have short life spans, and those that develop and reproduce slowly have long life spans. This difference is due to actual resources invested in the maintenance of the adult soma. There is now much evidence that long-lived mammals have much more efficient maintenance mechanisms than short-lived mammals. Thus, aging can be defined as the eventual failure of maintenance. It also became apparent that many different maintenance mechanisms exist, and that these depend on very many genes and a considerable investment in metabolic resources. Most individual theories of aging revolve around the failure of a given maintenance system, but as there are many of these, it is likely that most of the important theories have some degree of truth. A broad interpretation of the different degenerative changes during senescence should therefore be adopted, with the major conclusion that aging is multicausal. It is also evident that the evolved design of many components of complex animals is incompatible with indefinite survival. We can therefore conclude that this evolved design is intrinsically related to the fact of aging. This in turn means that aging cannot be reversed, although it may be modulated, as, for example, by calorie restriction.

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The Modulation of Lifespan by Natural Selection

Cited by 2 publications

References 19 publications

Ageing and the extinction of large animals

Ageing and the extinction of large animals

Aging is No Longer an Unsolved Problem in Biology

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