Category Science

When did agriculture begin?

Taking root around 12,000 years ago, agriculture triggered such a change in society and the way in which people lived that its development has been dubbed the “Neolithic Revolution.” Traditional hunter-gatherer lifestyles, followed by humans since their evolution, were swept aside in favor of permanent settlements and a reliable food supply. Out of agriculture, cities and civilizations grew, and because crops and animals could now be farmed to meet demand, the global population rocketed — from some five million people 10,000 years ago, to more than seven billion today.

There was no single factor, or combination of factors, that led people to take up farming in different parts of the world. In the Near East, for example, it’s thought that climatic changes at the end of the last ice age brought seasonal conditions that favored annual plants like wild cereals. Elsewhere, such as in East Asia, increased pressure on natural food resources may have forced people to find homegrown solutions. But whatever the reasons for its independent origins, farming sowed the seeds for the modern age.

Cattle, goats, sheep and pigs all have their origins as farmed animals in the so-called Fertile Crescent, a region covering eastern Turkey, Iraq and southwestern Iran. This region kick-started the Neolithic Revolution. Dates for the domestication of these animals range from between 13,000 to 10,000 years ago.

Genetic studies show that goats and other livestock accompanied the westward spread of agriculture into Europe, helping to revolutionize Stone Age society. While the extent to which farmers themselves migrated west remains a subject of debate, the dramatic impact of dairy farming on Europeans is clearly stamped in their DNA. 

 

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In the history of agriculture, what are cultigens?

A cultigen (from the Latin cultus – cultivated, and gens – kind) or cultivated plant is a plant that has been deliberately altered or selected by humans; it is the result of artificial selection. These anthropogenic plants, for the most part, have commercial value in horticulture, agriculture or forestry. Because cultigens are defined by their mode of origin and not by where they are growing, plants meeting this definition remain cultigens whether they are naturalised in the wild, deliberately planted in the wild, or growing in cultivation.

Notably, agriculture does not appear to have developed in particularly impoverished settings; domestication does not seem to have been a response to food scarcity or deprivation. In fact, quite the opposite appears to be the case. It was once thought that human population pressure was a significant factor in the process, but research indicated by the late 20th century that populations rose significantly only after people had established food production. Instead, it is thought that—at least initially—the new animals and plants that were developed through domestication may have helped to maintain ways of life that emphasized hunting and gathering by providing insurance in lean seasons. When considered in terms of food management, dogs may have been initially domesticated as hunting companions, while meat and milk could be obtained more reliably from herds of sheep, goats, reindeer, or cattle than from their wild counterparts or other game animals. Domestication made resource planning a more predictable exercise in regions that combined extreme seasonal variation and rich natural resource abundance.

 

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Which spiders do Victorians mistake for a Sydney funnel-web?

Victorian funnel-web, trap-door spiders and mouse spiders do Victorians mistake for a Sydney funnel-web. The Melbourne trap-door spider, stanwellia grisea, looks similar to the Sydney funnel-web. It is found throughout the Melbourne metropolitan area. The Melbourne trap-door spider is quite aggressive, but rarely bites. If you are unlucky enough to be bitten, it can be painful but not dangerous. Mouse spiders, missulena bradleyi, are found on the outskirts of Melbourne, on the Mornington Peninsula and in the drier western areas of Victoria. They can also be aggressive but rarely bite. The bite is not known to be dangerous. Victorian funnel-web, mouse and trap-door spiders all live in burrows in the ground.

Funnel-webs burrow in sheltered sites under logs and rocks where they can find a cool and humid climate. Funnel-webs rush out of their burrow when potential prey, such as beetles, cockroaches, small lizards or snails, walk across silken trip-lines that the spider has placed around the outside of its burrow. They then return to their burrow to eat their meal.

 

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Is it true that all female spiders eat the males after mating?

No, this is not true. Some female spiders do not eat their mates, however some species will eat the male, if they are smaller or food is scarce.

“We were surprised to find that such a simple characteristic such as how small males are relative to females has such a large effect on the frequency of sexual cannibalism,” Wilder said.

Perhaps the most well-known example of spider-women eating spider-men is the black widow. But even that cannibalism case is overstated. For most of the many species of black widows, cannibalism is the exception, not the rule, according to Rod Crawford of the Burke Museum of Natural History & Culture at the University of Washington.

 

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Are daddy long-legs the most poisonous spiders in the world?

It turns out that the notion is false on both counts. But a little clarification is needed.

According to entomologists at the University of California, Riverside, the term “daddy longlegs” is commonly used to refer to two distinct types of creatures: opilionids arachnids with pill-shape bodies and eight long legs that are actually not spiders, and pholcids, which have long legs and small bodies, and thus resemble opilionids, but which are true spiders.

Pholcids, or daddy long-legs spiders, are venomous predators, and although they never naturally bite people, their fangs are similar in structure to those of brown recluse spiders, and therefore can theoretically penetrate skin. For these reasons, “This is most probably the animal to which people refer when they tell the tale,” the entomologists assert.

But is pholcids’ venom extremely poisonous? Surprisingly, because they almost never bite, scientists have never bothered to conduct research to determine their venom’s toxicity to humans . In 2004, the Discovery Channel show “Mythbusters” stepped in to fill this knowledge void. The team set out to coax a daddy longlegs spider into biting the arm of the show’s co-host, Adam Savage.

 

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Is the deadly Sydney funnel-web spider found in Victoria?

Sydney funnelweb spiders are not found in Victoria.

The two Victorian funnelweb spider species are relatives of the Sydney funnelweb spider. 

Funnelweb spiders are found around the east coast and the highlands of Australia (from Queensland to Tasmania) and small regions of South Australia. Most are found on the ground where they build burrows in moist, cool, sheltered areas, but some are tree-dwelling. They are regarded to be the most notorious of the Australian spiders due to their highly toxic and fast-acting venom. However, out of at least 40 species, only the male Sydney funnelweb spiders have been responsible for recorded deaths

Funnelweb spiders have a shiny black head and legs, and black to brown abdomen covered in fine hairs. The females are slightly larger (35 mm) than the males (30 mm).

The female produces a pillow-shaped silk egg sac, which she defends vigorously if disturbed. The spiderlings hatch about 3 weeks later, and stay with the mother for a few months. Funnelwebs reach maturity in about 2–4 years. The females live for 10 or more years, whereas the males die 6–9 months after maturity.

 

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