Humans' ever spreading presence around the globe influences patterns of biological evolution in ways that we are just beginning to explore. On the Galapagos islands, a body of evidence shows that the effect of our presence is increasing.

Luis F. De León from University of Massachusetts, together with other 6 scientists spent two years observing Darwin's finches(雀类) to evaluate our effects on their behavior. They started by conducting feeding observations on coexisting finch species at sites that range from non-urban to urban. They also employed finch-human interaction experiments to test whether and how finches respond to human presence. To measure whether finch feeding preferences varied with the degree of urbanization, "cafeteria" experiments were carried out－finches were presented with a selection of human and native food items.

The scientists found that Darwin's finches fed almost on human foods like rice and cookies or introduced garden species at urban locations. In contrast, at non-urban sites, finches fed mainly on native plant species and insects. Interaction tests suggest that urban birds get more accustomed to the presence of humans. Finally, at all sites of regular human presence, finches preferred human foods to natural foods.

The researchers warn that exploiting urban environments might present challenges for organisms, including shorter lifespans brought on by the consumption of highly processed foods. Furthermore, the year-round availability of abundant human foods in urban environments might affect ecological and evolutionary processes that promoted species diversification. While the results clearly show a shift to human foods in urban sites, the adaptive significance of that shift is still an open question.

These findings also suggest that human behavior is the main driver of finch preference for human foods. The researchers propose a possibility that the effect of human behavior is facilitated by our tendency to feed birds, be it directly or inadvertently via food dropping or littering.

Angus Neish dared to hope that his fine-looking cattle, bred at Rodmead Farm in Wilt-shire, would nab a prize at the Royal Bath and West Show last month. The annual fair, held near Shepton Mallet, in Somerset, is England's oldest and grandest. As well as a fiercely competitive livestock parade, it features Morris dancing, sheep-shearing and a vintage fairground. Its pony-chariot races are second to none. Many contestants performed vigorously before a large crowd. 100, 000 turned out for some of the three-day show. 

Britons love a fair. No one is sure exactly how many shows there are across the country, but at least 400 days of such rural events happen annually across the country. Roughly one in ten Britons attend them each year. It appears their popularity is rising. 

In late June, it was the turn of the Royal Highland Show, near Edinburgh, where 217, 000 people—breaking a record set in 2019-rolled up. It is estimated that the event last year boosted nearby businesses by almost &40m($51m). 

Why do people go?Nostalgia(怀旧)is evidently a draw. At Bath and West, as colored flags flapped, visitors formed queues, bought cream teas and listened as a military band played wartime hits. Rural shows also have a purpose. Many fairs were founded to spread the knowledge of new farming technology among rural populations. Some of that mission lives on. 

A secondary goal is to better educate those who flood in from towns and cities—urban folk make up a decent share of those who pack the grounds. Some consumers also come armed with powerful knowledge of food supply chains—as well as sometimes picky personal preferences for organic, local, animal-friendly and environmentally sound products. Laura Williams, of the Royal Welsh Show, notes that visitors are"much more invested in farming and interested in where their food comes from"than in years past.

A last purpose, naturally, is for farmers to excel against their rivals in friendly competition. In this respect, Mr. Neish enjoyed an utterly successful day. In a first for Bath and West, his cattle scooped all four of the top prizes on offer in their categories. Such victories do not bring immediate, large financial rewards, but should boost the reputation of his breeding program. 

Zion National Park in Utah has plenty of trails, but Angels Landing may be the most breathtaking. Picture this. You begin the hike on the wide and well-maintained West Rim Trail. It follows the river and then crosses the bottom of the canyon, surrounded by 270-million-year-old layers of rock. Relaxing, right? Just wait for it. The trail then starts to climb via a series of switchbacks (急转弯) leading up the side of the mountain. Then more switchbacks: 21 tighter turns, called "Walter's Wiggles, " where elevation levels rapidly increase. Your heartbeat is probably rapidly increasing at this point, too. 

On top of Walter's Wiggles, you can stop for a stunning view (perhaps with a marriage proposal) and a restroom stop while you contemplate (仔细考虑) the final stretch of the hike. If you're afraid of heights, it's best to turn back now. The last stretch is the real test of bravery. 

The last half mile of the hike is what really ranks it as one of the nation's most dangerous. Angels Landing itself is a fin-like formation jutting (突出) 1, 500 feet out of the canyon, and this is where you make the final 500-foot climb. Guardrails and chains bolted (拴住) into the cliff help you keep from tumbling over the extremely steep ledge. You're literally living on the edge, and you don't want to trust the "angels" down there to catch you. Once you reach the top, however, it'll all be worth it: 360-degree views of the canyon make a great backdrop for kicking back and having a meal before you come back down the way you came. 

Angels Landing might be dangerous, but thankfully, not too many people have had fatal falls. According to the park website, seven people have died in the 100 years the park has existed. Still, this is a very vigorous hike. If you're out of shape, bringing young children along, feel ill or prone to fainting, or are just plain afraid of heights, opt for an easier trail. 

Angel's Landing is a great hike for most of the year, besides the cold winter months when the trails could become dangerously slippery. Summer is the most popular time of year — and therefore the most crowded — but it can also get extremely hot, so opt for an early morning hike while the temperatures are still mild. 

Sure, it's dangerous, but there's a reason this is one of Zion 's most popular hikes. If you're up for the challenge, Angels Landing will definitely deliver rewards. 

This article first appeared on Curiosity. com.