A RECENT expedition to New Jerseyorganised by the American Museum ofNatural History in New York, US,returned with a sizable haul from thefossilised world. The team led by DavidGrimaldi uncovered one of the richestdeposits of amber ever found. Thedeposits found in central New Jersey areestimated to be around 95-65 millionyears old. "It is scientifically the mostimportant of all amber fossils," saysGrimaldi.
Around 100 species of insects andplants trapped in the ancient tree sap areunknown to the world. Three tiny flowers - that had perhaps fallen from anoak tree - have been recovered fromapproximately 40 kg of amber. Theirdiscovery is of great significance to thescientific community as the flowers dateback to some 90 million years, whendinosaurs inhabited the earth. The flowers are the oldest fully preserved ones tobe found in amber. They may hold cluesto the origin of the flowering plants thatcurrently dominate the earth.
Apart from the oldest flowers, theNew Jersey amber deposit containsother specimens like the world's oldestfossilised mosquito with proboscissharp enough to pierce a dinosaur'sthick skin; the oldest moth whosemouth indicates its transition from abiting insect to one that sucks the nectarof flowers; and the oldest bitingblack fly.
Although amber is found mostly inconifers like pines, it occurs even insequoias and cedars apart from certaindecidous trees. The dried up tree resin,is believed to be a defence mechanismagainst wood-boring insects. It tricklesdown the bark of the wounded treesencapsulating the insect and hermeticallysealing the injured part of the trunksimultaneously. When the 'trees with thedried res 'in fall later, they get buried inthe soft sediment found at the bottom ofstill and shallow waters. Over millionsof years these resin molecules consolidate, forming a string of resin-beadswhich resemble plastic because of theirchemical inertness and, air and water-tight nature. The amber is not selectivein nature rather, it devours anythingthat comes its way.
Amber fossils give us clues as to thewhere and how of the preservation ofcertain plant and animal characteristicsor mannerisms. They may also revealwhether or not insects and flowers helpeach other in evolution. Preserved inamber are images from the past likemites riding on the backs of sweat bees,a leaf beetle spitting out a stream of noxious bubbles in self defense and spiders mating.
Although amber is an excellent preserver of ancient life forms, it is unable to prevent the fragmentation Of DNAstrands. DNA found in amber is scientifically very interesting as it happens to bethe best preserved protein on earth, withthe amber dehydrating the captive andthe terpenes in the resin acting as a fixative. Although scientifically the DNA maybe of importance, biologically it isworthless since it cannot be of use as ablueprint to generate life.
Genetic material has been extractedfrom a 17 million-year-old magnolialeaf, a 30 million -year- old termite anda 120 million-year-old weevil, butunlike what happens in the movieJurassic Park, scientists have not beenable to re-create a living entity from bitsof DNA.
Surprisingly, amber deposits that donot contain fossils may not be important to scientists and biologists, butcommand value as precious stones andare much sought after by artists andjewellers. Amber is found in a variety ofcolours (about 250 shades) like white,red, blue and green.