The researchers found.

There, for example in an estuary there more kilograms of trematode worms – parasites – than kilograms of birds, the researchers found.The study results have a potential impact on the perception of the role of parasites in the ecosystem. From an environmental perspective prevent parasites regulators regulators to numerically dominant ways, and as indicators of the health of a particular ecosystem. ‘No one debated whether it is important to understand for ensuring human well-being, how ecosystems function,’said Hechinger.

‘Parasites as much or even more, biomass important important groups of animals – such as birds, fish and crabs,’said Ryan Hechinger, a marine researcher at UCSB and co-lead author of the paper.. Until now , scientists have believed that because parasites are microscopic in size, it is a small part of the biomass in a habitat, while free-living organisms such as fish, birds and other predators make up the vast majority. ‘We quantified the biomass of free-living and parasitic species in three estuaries and discovered that parasites biomass biomass in these ecosystems,’said Armand Kuris, a zoologist at the University of California at Santa Barbara , and a lead author of the paper.This includes symbolic behavior like abstract and realistic art, and body decorations to threads shell beads, ocher and tattoo kits, Musical Instrument, bones, they did it artifact, stone blades and complex hunting and trapping technology, like bows, boomerangs and networks. – Professor Stephen Shennan, UCL the Institute of Archaeology, said: Modern humans are since of at least 160,000 to 200,000 years, but there are no archeological evidence to any technology on basic stone implements up to around 90,000 few years in Europe and west Asian that.

Population density leads to more exchanging ideas and abilities and prevents the loss by innovation. It is this ability maintenance of, combination with a higher probability out of useful innovations of modern the modern of human behavior out at various times in different over the world.. In the study, the UCL omissions took is that complex skills away generations may be only maintain are learned where is a critical level of interaction between people. Through computer simulations of social learning, they demonstrated that up and low – skilled groups could coexist over long periods of and in the level of skill she hanging in local population densities and the level of migrating between them kept.