Life Thrived After More Than 100 Meteorites Struck the Earth
Written by Fraser Cain
Yesterday we talked about the discovery of amino acids in meteorites. And then today comes news that there was an explosion of life (pardon the pun) after meteorites rained down more than 400 million years ago. Even though the Earth was struck by more than 100 1-km meteorites in a short period of time, life not only survived, it thrived.
The string of impacts occurred during the Ordovician period, between 490-440 million years ago. It wasn't quite life as we know it, but creatures were living on land, and organisms had evolved to fit every niche in the oceans.
According to planetary scientists, a disruption in the asteroid belt about 470 million years ago sent hundreds of space rocks out of their normal orbit, and into ours.
Over a few million years, more than 100 separate meteorites larger than 1 km across struck the Earth, throwing up a Sun-clogging shroud of dust. Plants, starved for sunlight, died, and the chains of life depending on them collapsed.
But incredibly, life thrived after this period, evolving into new and interesting life forms.
Researchers from the University of Copenhagen and Lund University gathered together chemical samples from meteorites, fossils, and examined several craters in Sweden. The Lockne crater, for example, is located in northern Sweden and has a diameter of 7.5 km across.
They found evidence for the thriving life forms in layers newer than the ones containing debris from the meteorite strikes.
"You could say that biological evolution experienced a serious boost within a relatively short period of time. And, as is the case with, for example, volcanic eruptions or large forest fires, the impacts initially had a devastating effect on all life, but from the ashes arose a much richer fauna than had existed previously," said Dave Harper from the University of Copenhagen.
This is research we've seen before. Paleontologists announced earlier this year that life can bounce back quickly from an extinction event, but it takes a long time for the true diversity of life to reappear. So, after most life is wiped out by an asteroid, the cockroaches and rats take over. You might have the same number of creatures, but it takes many years before you get rich ecosystems with butterflies and giraffes too.
Original Source: Nature Geoscience
Filed under: Asteroids
March 14th, 2008 at 11:38 pm
Hopefully, the wayward meteorites have cleared their course & we won't get bashed again. Sweden must have been attached to some huge landmass back then, probably Eurasia & closer to tropics.
Shocked minerals & quartzes characterize meteor impacts from Central America too, incl Chicxiulub in Yucatan which contributed to Permian/Triassic 250mya extinction. Some theories claim this Dinosaur extinction began before & continued after(by millions) the impact, so it may have occured gradually, including other factors. The great Flowering began here w diploid Angiosperms outcompeting haploid reproducing ferns & mosses. Soon birds, bats & bees pollinated them.
The survivors of the Ordovician shocks inhabited the deeper oceans. Bivalves(sim to clams), coelenterates (jellies, squid, nautilus, oct), echinoderms(sponges), & mollusks were buffered from climate change. No back bones here. Biodiversification would have filled the vacated or newly-formed biological niches w/o much competition. The other major phyla probably developed terrestially after the smoke cleared, esp vertebrates.
Yes, amino acids pooled together tend to aggregate. Peptide bonds are favorable, exothermic, they give off
energy. UV, heat or chem energy could break bonds & stir up the primordial soup. Then the proteins form manipulable hydrogen bonds & stronger sulphur bonds as they fold upon themselves. Quaternary structures can then form between proteins. Proteins perform life's functions, not nucleic acids, whose only role is regulating proteins, fats, carbs & metabolic byproducts. Conceivably proteins could perform perfunctory life functions & die wholesale w/o replicating, patiently awaiting the day when nucleic acids develop & they form a partnership with this nucleic virus. From there you conjecture bacterium or protozoan's swallowing organs they need (mitochondria, ribosomes, lysosomes, etc).
Since they claim to find amino acids in meteorites, then the Panspermia theory gets a big boost. Is there life in space? Well, I hope there's life out there. And you know what they say "Where there's Hope, there's Life".
Kingdom: Animalia Class: skipped class Phylum: Dischordata Order: hor d'ouvre Family: Hominidae
Genus: Vulcan Species: Spockian
March 15th, 2008 at 12:22 am
Erm, as to that "meteor impacts from Central America too, incl Chicxiulub in Yucatan which contributed to Permian/Triassic 250mya extinction," the impactor that made the crater at Chicxulub is associated with the End-Cretaceous Event, 65 myr ago, not 250 myr. Anyway, I'm curious about the causes that period of 100 bolide strikes during the Ordovician. This was *wat* after the Late Heavy Bombardment. So where did all those bolides come from, and could that ever happen again?
March 15th, 2008 at 5:53 am
Why do Paleontologists seem so surprised. When life is established it is difficult for new life to get started a disaster such as this gives new life an opportunity to develop which it can not do. Remember when a major disaster of this type happens other changes take place giving other life forms opportunities.
March 15th, 2008 at 7:21 am
[...] con mariposas y jirafas también. Autor: Fraser Cain Fecha Original: 14 de marzo de 2008 Enlace Original Articulos RelacionadosLos meteoritos fueron una fuente rica para la sopa primordial La sopa [...]
March 16th, 2008 at 3:35 am
Why is 'explosion of life' a pun that requires to be pardoned?
explode=ex+plaudere='to drive out by clapping or (the opposite of) applauding'
March 16th, 2008 at 8:45 pm
If most of these "meteorites " (asteroid/comets or my preference microplanets) were around 1km in size then many microscopic lifeforms would be unrattled - at least on a global scale:
http://users.tpg.com.au/horsts/climate.htm
One such impact every 10,000 years gives plenty of time for recovery.
It is "higher" organisms that build dwellings on coastal flats and rely on just-in-time food supplies that are vulnerable to these minor impacts.
March 17th, 2008 at 4:11 pm
Sweden must have been attached to some huge landmass back then, probably Eurasia & closer to tropics.
Eurasia didn't exist during the Ordovician. What's now Sweden along with the rest of northern, central, and eastern Europe made up the smallish continent Baltica, which towards the end of the Ordovician collided with Laurentia, a continent consisting of what's now the core of North America. Baltica was in the low southern latitudes during this time.
March 19th, 2008 at 6:26 pm
I was just wondering if anybody else made the connection: the story said, "amino acids in meteorites". Is it possible the new amino acids from meteorites themselves caused the "explosion of life" after the impacts?