Thanks to Birds we have no more Giant Bugs

Sure, they provide the soundtrack of spring and are often lovely to look at. But a new study may offer the best reason yet to appreciate birds: the general absence of gigantic insects from our daily lives.

Today insects are among the smallest creatures on Earth, but about 300 million years ago, huge bugs were fairly common. The dragonfly-like griffinfly, for example, had a wingspan of about 70 centimetres—a little bit smaller than a crow’s. Today’s widest-winged insects are butterfly and moth species that span about a foot (30 centimeters).

The prehistoric bugs’ incredible growth was fueled by an atmosphere that was more than 30 percent oxygen, compared with 21 percent today, experts say. The extra oxygen gave bugs more energy per breath, allowing them to power bigger bodies.

But things changed about 150 million years ago, during the Jurassic period, when the first birds appeared alongside dinosaurs. After birds took to the skies, winged insects stopped growing bigger—even as oxygen levels rose.

As to why the big bugs might have fallen to birds, the maneuverability of any sort of flying thing really scales with size. Small things are much more maneuverable than large things. In other words, large insects may have been easy targets. Another possibility is that birds may simply have eaten the big bugs’ lunch. The birds may have m0re successfully competed for food sources.

The largest insects today could perhaps be three times as large as they currently are, based on current oxygen levels – hip, hip, hooray for birds!!! Learn more here.

Humanity weighs in at 287 million tonnes

Humanity weighs more than 5400 Titanics. Biologists have calculated the total mass of all humans living on Earth, which they say is a better way of measuring our impact on the planet than simply counting our numbers.

Scientists used 2005 data on body mass index (BMI) and average height to work out the average body mass of people for each country. By factoring in population data, they calculated that the total adult population weighed 287 million tonnes. The true figure is larger – as they did not include children – and will grow over the coming decades. Learn more here.

The World’s Population Density, Visualised

It’s difficult to get a handle on the population density around the world. Fortunately, this visualisation makes it a little easier to get your head round it.

Put together by Derek Watkins, it’s actually interactive: you get to use a slider to shift the population density and see it change before your eyes. You should head to his website to try it out for yourself. The image above shows the areas around the world that house five people per square mile or more.

Proposals to Relocate Endangered Species

At the beginning of the 21st century, with 7 billion humans competing for space and resources on a rapidly warming planet, moving species around may be a legitimate option.

It’s called assisted migration. Often the goal is to save endangered plants and animals, though not always. Sometimes the goal is to restore ecological balance.

For example, consider the hypothetical possibility of introducing elephants and Komodo dragons to Australia. At first it sounds mad, but what’s happening now in Australia is a form of madness, too. Massive wildfires that have become a regular and lethal fact of Australian life don’t only represent climate change or natural susceptibility, but the buildup of vegetation that until 50,000 years ago would have been eaten by Australia’s now-extinct megafauna.

Elephants could fill that role again. The idea of introducing elephants may seem absurd, but the only other methods likely to control gamba grass involve using chemicals or physically clearing the land, which would destroy the habitat. Using mega-herbivores may ultimately be more practical and cost-effective. Komodo dragons wouldn’t do much for fires, but they would eat feral pigs and buffalo, the targets of ongoing and largely unsuccessful animal control efforts. Learn more relocation proposals here.

A dam gets blown up to help salmon

Salmon lead a very interesting life.

Starting out as small eggs in a stream bed, they hatch and begin their journey downstream towards the ocean. They spend a couple of years in the streams and rivers growing to a juvenile stage. The young adult salmon then head out to sea and spend several years swimming around. Once they have fully matured, they will swim back to their original stream or river to spawn, or lay their eggs in the water.

Their upstream journey is a challenging one, swimming upstream against rugged rapids, leaping over rocky waterfalls, traversing fish ladders, avoiding fishermen nets and hooks, and staying clear of hungry bears.

But no salmon can overcome the difficulty of traversing a dam!

For 98 years, the 125-foot high Condit Dam in southeastern Washington State, USA, held back the White Salmon River, creating a serene lake, but choking off the waterway to salmon. So, in an historic effort, the dam was dramatically breached, and ecologists hope the increased flow of water will restore the waterway to fish and other aquatic organisms, as well as the birds and mammals that rely on them.

Check it out:

7 Billion: How Did We Get So Big So Fast?

For context, let’s consider a few other numbers. The first: 10,000. That’s approximately how many Homo sapiens existed 200,000 years ago, the date at which scientists mark the divergence of our species from the rest of Homo genus, of which we are the sole survivors.

Now the world’s population is 7 billion people. How did it happen?

However, it must be noted that, as we’ve become big, much of life had to get out of the way. When modern Homo sapiens started scrambling out of East Africa, the average extinction rate of other mammals was, in scientific terms, one per million species years. It’s 100 times that now, a number that threatens to make non-human life on Earth collapse.

Learn more here.

Seven billion

On 31 October, a newborn baby somewhere in the world will become the 7 billionth member of the human race. Or so says the UN – alternatively, this date could be at least a year too early.

Behind the UN’s uncertainty may lie outdated and unreliable census data. The suspicion is that millions of births and deaths have not been counted and there is huge uncertainty about the rate at which women are giving birth.

The precise “day of 7 billion” may not matter much. But the inaccuracies make it harder to answer a more important question: is human population set to peak within the next few decades or will it carry on growing beyond that?

Learn more here or here.

Coral reefs ‘will be gone by end of the century’

Coral reefs are on course to become the first ecosystem that human activity will eliminate entirely from the Earth, a leading United Nations scientist claims. He says this event will occur before the end of the present century, which means that there are children already born who will live to see a world without coral.

The predicted decline is mainly down to climate change and ocean acidification, though local activities such as overfishing, pollution and coastal development have also harmed the reefs. Learn more here.

Human poo killing coral

Coral reef ecologists have laid a persistent and troubling puzzle to rest. The elkhorn coral, named for its resemblance to elk antlers and known for providing valuable marine habitat, was once the Caribbean’s most abundant reef builder. But the “redwood of the coral forest” has declined 90% over the past decade, in part due to highly contagious white pox disease, which causes large lesions that bare the coral’s white skeleton and kill its tissue.

Now, after nearly a decade of data collection and analysis, researchers have fingered the cause of the affliction: human excrement. The finding represents the first example of human-to-invertebrate disease transmission and suggests a practical approach for halting the disease’s spread. Learn more here or here.

8.7 million species on Earth

Fancy discovering a new species? It shouldn’t be too difficult, as the best estimate yet of how many species the planet supports comes up at 8.74 million. Although about a quarter of those are in the sea, some 7.5 million species remain to be discovered.

Previous estimates were around 5.5 million, but the new number means scientists have cataloged less than 15 percent of species now alive—and current extinction rates mean many unknown organisms will wink out of existence before they can be recorded.

The study was driven by a simple question: “Are we within reach of finding all species, or are we way off?”.

“The answer is, we are way off!” Learn more here or here.