Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Old age, death and evolution

05.02.2007
A hypothesis of the evolutionary origin of ageing has been suggested by A.V. Makrushin, specialist of the I.D. Papanin Institute of Biology of Inland Waters (Russian Academy of Sciences) and published in the Progress of Gerontology journal (2006, issue 19). According to this hypothesis, Metazoa animals had initially possessed physical immortality, but lost this property in the course of evolution.

The first Metazoa animals possessed a modular structure, consisting of several identical individuals combined into a colony. The colony appeared due to gemmation, where sponges grow out of the body of another sponge, to form a colony of perfectly identical creatures. A sponge colony is motionless. If the environment changes, the colony cannot move but can change shape. This happens as follows: some members of the colony are born, others - atrophy, or, as the researchers say, undergo involution.

A signal to involution for some members is formation of other members. The members of a growing colony use substances released after the old members atrophy as building materials. Since all modules of the colony are genetically identical, the death of some part of them does not damage the gene pool. Therefore, this ancient extinction mechanism served exclusively for changing the colony shape and did not promote evolution of modular organisms.

In the course of evolution, animals reproducing in an asexual way started to separate completely from each other. A lot of Polychaeta worms can reproduce by division or even by gemmation, but each derived organism already lives separately. However, in such way of reproduction, gemmation of descendants causes involution of parental tissues as before.

... more about:
»AGE »Metazoa »colony »death »gemmation

The difference is that the parental organism dies in this case, so, in A.V. Makrushin’s opinion, this can be already considered ageing. However, such ageing does not impact the evolution yet, because the genotype of the parents that died of old age continues to exist in their offsprings. However the Metazoa animals continued to evolve and finally did away with gemmation. Each of their offsprings, with the exception of monozygotic twins, possessed a unique genotype, and the loss of an individual was an irreplaceable genetic loss. And the mechanism of gerontal involution of tissues, which was preserved by these advanced creatures, resulted now not only in the death of a single individual, but in changing the gene pool of an entire species. Thus ageing began to influence the species evolution.

All Metazoa animals are descendants of modular organisms, from which they inherited ability to gerontal tissue involution. This is a universal and very ancient mechanism of ageing. Probably, it originated several times in the course of evolution of different groups of modular multicellular animals.

A.V. Makrushin also gives other examples where, from his point of view, ageing happens according in line with other mechanisms. For example, some hydra species die a natural death, having completed reproduction, but some adult insects die of hunger as their oral organs are underdeveloped. Their life span is determined by the fat reserve accumulated during their larval existance.

However, the primary ageing mechanism of the multicellular is gerontal tissue atrophy. Now, this mechanism is a key part of evolution, including human development, which means we have to grow old.

Nadezda Markina | alfa
Further information:
http://www.informnauka.ru

Further reports about: AGE Metazoa colony death gemmation

More articles from Life Sciences:

nachricht Researchers identify potentially druggable mutant p53 proteins that promote cancer growth
09.12.2016 | Cold Spring Harbor Laboratory

nachricht Plant-based substance boosts eyelash growth
09.12.2016 | Fraunhofer-Institut für Angewandte Polymerforschung IAP

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Electron highway inside crystal

Physicists of the University of Würzburg have made an astonishing discovery in a specific type of topological insulators. The effect is due to the structure of the materials used. The researchers have now published their work in the journal Science.

Topological insulators are currently the hot topic in physics according to the newspaper Neue Zürcher Zeitung. Only a few weeks ago, their importance was...

Im Focus: Significantly more productivity in USP lasers

In recent years, lasers with ultrashort pulses (USP) down to the femtosecond range have become established on an industrial scale. They could advance some applications with the much-lauded “cold ablation” – if that meant they would then achieve more throughput. A new generation of process engineering that will address this issue in particular will be discussed at the “4th UKP Workshop – Ultrafast Laser Technology” in April 2017.

Even back in the 1990s, scientists were comparing materials processing with nanosecond, picosecond and femtosesecond pulses. The result was surprising:...

Im Focus: Shape matters when light meets atom

Mapping the interaction of a single atom with a single photon may inform design of quantum devices

Have you ever wondered how you see the world? Vision is about photons of light, which are packets of energy, interacting with the atoms or molecules in what...

Im Focus: Novel silicon etching technique crafts 3-D gradient refractive index micro-optics

A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.

Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...

Im Focus: Quantum Particles Form Droplets

In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.

“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ICTM Conference 2017: Production technology for turbomachine manufacturing of the future

16.11.2016 | Event News

Innovation Day Laser Technology – Laser Additive Manufacturing

01.11.2016 | Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

 
Latest News

Researchers identify potentially druggable mutant p53 proteins that promote cancer growth

09.12.2016 | Life Sciences

Scientists produce a new roadmap for guiding development & conservation in the Amazon

09.12.2016 | Ecology, The Environment and Conservation

Satellites, airport visibility readings shed light on troops' exposure to air pollution

09.12.2016 | Health and Medicine

VideoLinks
B2B-VideoLinks
More VideoLinks >>>