Linkhome Documentiportfolio Videovideo Fotohistory
»
S
O
C
I
A
L

B
A
R
«
La Terra come unico organismo vivente

Ci vogliono più di dieci anni affinchè questa ipotesi venga articolata meglio e riesca ad essere maggiormente accettata dalla comunità scientifica internazionale. Fondamentali sono le collaborazioni tra Lovelock e altri scienziati che si occupano di oceani e di atmosfera. Di particolare importanza è stato l’incontro avvenuto nei primi anni Settanta con la microbiologa Lynn Margulis dal quale è stato messo in luce il ruolo fondamentale che la comunità di batteri svolge nella fisiologia di Gaia.

Il nome scelto da Lovelock (Gaia è la dea della Terra nell’antico mito greco) da un lato si è rivelato essere estremamente evocativo, ma da un altro lato ha contribuito a far sì che venisse adottato dal movimento della New Age, con conseguente imbarazzo da parte della comunità scientifica. Dalla combinazione dei molteplici studi che si sono susseguiti negli anni, verso la fine del secolo scorso l’ipotesi Gaia si struttura in una vera e propria teoria che descrive il nostro pianeta nel suo insieme (a questo aspetto deve aver contribuito anche la possibilità di vederlo dallo spazio attraverso le prime fotografie scattate dagli astronauti) evidenziando come questo si comporti esattamente come un unico essere vivente. Le componenti biotiche e quelle abiotiche sono in stretta relazione tra loro e la complessa rete di interazioni dinamiche consente a questo enorme organismo di autoregolarsi. Questa è, infatti, una delle proprietà degli esseri viventi. Così come gli animali a sangue caldo, anche la Terra è in grado di mantenere costante (entro certi limiti) la propria temperatura. E così come fanno tutti gli organismi viventi, tra cui quelli più piccoli come i batteri, anche la Terra rinnova e riequilibra i costituenti chimici che la compongono. I suoli, i mari e l’atmosfera si scambiano continuamente atomi e molecole. Questo scambio è inevitabile dal momento che gli ecosistemi che costituiscono Gaia hanno a disposizione soltanto una quantità limitata di elementi chimici (dall’esterno provengono solo trascurabili contributi con le meteoriti). La vita prevede quindi un continuo riciclo di tali elementi essenziali. Già nel corso della nostra esistenza, gli atomi che compongono le singole parti del corpo lo fanno per un periodo limitato prima di essere eliminati e rimpiazzati attraverso i processi di nutrizione, eliminazione e respirazione. A livello globale questo “movimento” chimico viene descritto con l’impiego di quelli che vengono definiti i cicli biogeochimici. Tali cicli coinvolgono sia le componenti organiche che quelle inorganiche degli ecosistemi e sono caratterizzati da tempi “geologici”. Tra questi ci sono il ciclo dell’azoto, dell’ossigeno, dello zolfo, ecc. La conoscenza del ciclo del carbonio è oggi di particolare rilevanza perché è quello che ci permette di descrivere la formazione dei giacimenti di combustibili fossili e il rilascio di anidride carbonica nell’atmosfera. Ad ogni modo, gli studi ci dimostrano che tutti i cicli biogeochimici sono in intima relazione tra loro e, quindi, che una più corretta conoscenza dei fenomeni a loro legati sia perseguibile soltanto in seguito a un’approccio sistemico, per il quale la teoria di Gaia risulta appunto particolarmente utile.

A cura di Alice Benessia, Maria Bucci, Simone Contu, Vincenzo Guarnieri.


120 interventi  
  • Wilson ha scritto:
    18 novembre 2014 alle 04:28

    Lost credit card Jr Tylenol For the longest time over the first half, it was pretty much apparent they were a team in decline with a need to start looking toward the future and acquiring some prospects to bolster a mostly barren farm system. But then the Nationals continued to underachieve, the front-running Atlanta Braves started coming back to the pack and the Phillies went on an 8-3 run leading into the All-Star break. When they pummeled the Mets in the first game of this series, it put them over .500 for the first time since June 6 and enabled them to leapfrog over the Nationals into second place. Now, after two straight losses to the Mets, they are back under .500 and only the continued losing on the Nationals’ part is keeping the Phillies in further suspense.

  • Maya ha scritto:
    18 novembre 2014 alle 13:35

    I wanted to live abroad easy approval cash advance On Tuesday, after hearing arguments by lawyers representingsewer-system customers that disclosures were inadequate, U.S.Bankruptcy Judge Thomas Bennett approved the massive disclosureplan and set the stage for votes by creditors. If approved bycreditors, the plan must still be confirmed at a hearingexpected to be held on Nov. 12.

  • Hiram ha scritto:
    18 novembre 2014 alle 17:40

    How long have you lived here? http://www.beachinthecity.com/index.php/programm limovan 7.5 mg forums “The challenge in that space is how foldable is foldable,” he said, noting that there is a threshold before a screen can no longer bend. “From a consumer perspective they want it as small as possible. They want to fold it and put it in their back-pocket and it’s got to be durable to withstand that.”

  • Markus ha scritto:
    19 novembre 2014 alle 00:05

    It’s funny goodluck cleocin iv Find out by putting backpacks on some of the birds, backpacks crammed full of sensors that will record their every move and transmit all that data back to scientists who could learn a lot about flying critters that many claim are modern dinosaurs.

  • Cedric ha scritto:
    19 novembre 2014 alle 05:42

    very best job cheque cashers ho Could the Giants, who so often find themselves “scratching and clawing” into the playoffs, as corner Terrell Thomas likes to say, fight back? Perhaps, but they would prefer not to even find out. “This is a big matchup for us at home, start of our home season,” Thomas said, “and we don’t want to be 0-2.”

  • Aiden ha scritto:
    19 novembre 2014 alle 08:15

    Where do you live? loans for bad credit 30 days or more to pay back “If this scandal worsens and if more countries put a ban onNew Zealand’s dairy imports … then I would imagine the NewZealand dollar would weaken,” said Jane Foley, senior currencystrategist at Rabobank, adding that it could drop toward $0.70.

  • Josef ha scritto:
    19 novembre 2014 alle 08:32

    I’m a housewife http://www.dmkdrillingfluids.com/index.php/products/obmc rogaine foam cheapest “This is the biggest driver in higher bills,” it said. But”taken together the government’s policies mean that householdenergy bills will be on average 11 percent, or 166 pounds, lowerin 2020 than if we just sat on our hands and did nothing.”

  • Alfred ha scritto:
    19 novembre 2014 alle 16:57

    I really like swimming http://www.irlandaitaliana.com/our-promoters/ tennessee quick cash Coconino County Sheriff’s officials say the names of the married couple were being withheld until relatives could be notified. The man and woman lived outside the United States, but their hometowns and ages weren’t immediately available.

  • Murray ha scritto:
    19 novembre 2014 alle 21:33

    I’d like to send this to price of mifepristone and misoprostol Alcoa expects a 9 to 10 percent increase in aluminum demandthis year from the aerospace sector, driven by a recent flurryof aircraft orders at the Paris Air Show and an already-largebacklog of orders within the aerospace industry. It also seesincreased demand from the automotive, commercial transportationand construction industries.

  • Irwin ha scritto:
    20 novembre 2014 alle 01:21

    I’m a partner in http://philippinespeculativefiction.com/intro.html propranolol migraine prophylaxis children Some 70 per cent of almost 200 respondents to the survey bydata provider Rigzone believe the British government was rightto offer incentives to communities where hydraulic fracturing,known as fracking, and horizontal drilling will be used.

  • Nolan ha scritto:
    20 novembre 2014 alle 04:09

    One moment, please confer cost of voltaren gel stadium An Israeli official, speaking on condition of anonymity, said late on Sunday that no date had been set for sending negotiators to Washington, confounding Kerry’s expectations that talks there could begin “within the next week or so”.

  • Marvin ha scritto:
    20 novembre 2014 alle 09:39

    One moment, please ambien take 2 10mg Taking to Twitter, in what must have been a late night rant stateside, the “murder my vagina” star wrote: “My Broken Nose Is Making The Bone Under My Eyes Protrude So I Won’t Stop Getting Surgery Until That Bone Is Shaved Off.”

  • Mohamed ha scritto:
    20 novembre 2014 alle 10:06

    Can I use your phone? freezing cash advance in hamilton peering It was an impressive outing for Harvey, even though Mike Trout drilled the first pitch of the game, a 97-mph fastball, inside the first base line for a leadoff double. Harvey struck out three, gave up one hit and also hit Robinson Cano above the knee with a 96 mile-per-hour fastball, although Cano wasn’t badly hurt.

  • Randy ha scritto:
    20 novembre 2014 alle 11:24

    I’d like to speak to someone about a mortgage http://www.denebcorp.com/index.php/mac-exchange 1000 payday loans from lender direct The California Public Employees’ Retirement System (Calpers)has fiercely opposed San Bernardino’s bankruptcy since theSouthern California city asked for protection from its creditorsin 2012. The city, reeling from a housing bust, a decades-longdecline in manufacturing, and soaring employee salary andpension costs, said it had run out of cash to meet its dailyobligations.

  • Fifa55 ha scritto:
    20 novembre 2014 alle 13:52

    I’ve been made redundant kamagra online bestellen nachnahme By letting Rivers go and then trading Paul Pierce and Kevin Garnett to the Nets last week, and now hiring a coach who has never been involved in the NBA at any level, the Celtics are doing anything but trying to win their next title. They’re expected to move their last big chip, Rajon Rondo, when he returns from a major knee injury sometime this season.

  • Florentino ha scritto:
    20 novembre 2014 alle 20:58

    How many more years do you have to go? faint nicholas standard bank personal loans presently South African police took six months to investigate the shooting before indicting Pistorius in August on charges of murder and illegal possession of ammunition, and included nearly 20 forensic experts in their list of over 100 state witnesses for the blockbuster trial. Pistorius’ lawyers now have seven months to prepare his defense and draw up their own list of witnesses.

  • Vida ha scritto:
    21 novembre 2014 alle 05:38

    How would you like the money? http://sceeventgroup.com/nj-wedding-djs/ buy zetia The number of children who get measles vaccinations in Rwanda has been steadily climbing since 2001. But in June of last year, the United Nations reported a sudden drop in coverage from 97 percent to 80 percent.

  • Ethan ha scritto:
    21 novembre 2014 alle 12:49

    Very interesting tale buy clomipramine india Some speculated the trip was approved because Beyonce and Jay-Z were buddy-buddy with President Barack Obama. The couple has donated more than $40,000 total to his 2008 and 2012 presidential campaigns.

  • Camila ha scritto:
    21 novembre 2014 alle 15:58

    I came here to study canoe utmost personal loan contract template free gloom madly After tapping the artist as its creative director earlier this year, the brand is hoping to shed its image as a low-brow blue collar sud with its latest release, Bud Light Platinum, targeted towards young, creative, urban hipster types.

  • Taylor ha scritto:
    21 novembre 2014 alle 16:01

    this post is fantastic http://greenwoodsstatebank.com/personal-loans/ payday loans that accept metabank accounts India is the biggest overseas source of medicines to the United States and is home to over 150 FDA-approved plants, including facilities run by global players. Pharmaceutical exports from India to the United States rose nearly 32 percent last year to $4.23 billion.


Intervieni

Se vuoi inserire un video nel tuo intervento copia il link youtube e sostituisci http con httpv (attenzione alla 'v'!)

Powered by PerformingMediaLab/Pie