Posted in Science & Nature

Endling

Extinction is when there are no more members of a given species left. Countless species have come and gone throughout history, such as the dinosaurs. We are currently going through the most recent episode of mass extinction where a vast number of species are being wiped out from the face of the Earth. The cause of this mass extinction is us.

So-called the Anthropocene Extinction, modern humans have been responsible for the extinction of millions of species over the course of our history. This ranges from the death of megafauna such as the woolly mammoth, to the extermination of the dodo on Mauritius, to the imminent extinction of the Northern white rhinoceros (with only two female rhinos surviving). This is the result of over-hunting, climate change, habitat destruction and predator and disease introduction.

Because of the sheer number of extinctions caused and threatened by us, we have also observed many hauntingly depressing stories of identifying the last member of a species. For example, we know that the last passenger pigeon named Martha died at the Cincinnati Zoo in 1914. The last Tasmanian tiger (thylacine) named Benjamin died in 1936, neglected in a zoo. These poor creatures who are the last of their kind are called endlings.

A particularly sad endling story is that of a Hawaiian bird species known as the Kaua’i ʻōʻō. They are an extinct species of honeyeater bird that could be identified by their strikingly rich, golden yellow leg feathers. The Kaua’i ʻōʻō were also famous for their flute-like duet songs sang between lifelong mating pairs.

The Kaua’i ʻōʻō became threatened as mosquitoes were introduced to the island of Kaua’i by sailors. The mosquitoes transmitted deadly diseases which decimated the population. To escape the mosquitoes, the birds retreated to higher ground. However, the Kaua’i ʻōʻō were cavity nesters, meaning that they made nests in tree hollows, which are found in fewer numbers at high altitudes. This meant that the birds failed to find nesting grounds and their numbers dwindled further.

The last mating pair was last observed in 1981. Despite ornithologists attempting desperately to protect this pair, they could not locate the female after a devastating hurricane struck the island in 1982. Several years later, ornithologist Jim Jacobi was surveying the Alaka’i reserve when he heard the unmistakable call of the Kaua’i ʻōʻō. He quickly used his tape recorder to record the Kaua’i ʻōʻō’s call. When he replayed the tape to the group, he noticed to his surprise that the male Kaua’i ʻōʻō had flown back towards them. He stared in wonder, then realised: the bird had returned because he had thought it heard another bird calling him; a call it hadn’t heard in however long.

We can still listen to this recording of the Kaua’i ʻōʻō endling. We can hear the clear lack of its duet partner’s call – a deafening silence symbolising the death of a species.

The saddest part of this story is knowing that even though we may never know their name or how their call sounds, countless endlings have died a lonely, quiet death all around the world, marking a full stop to their species’ epic narrative.

You can hear the Kaua’i ʻōʻō endling’s call here:

Posted in Science & Nature

Lizard People

What would the world be like if the dinosaurs had not gone extinct? In 1982, palaeontologist Dale Russell proposed a thought experiment regarding the possible evolutionary path of a species called Troodons. The Troodons were small, bird-like dinosaurs from the later periods of the reign of dinosaurs. They grew up to 2.4m in length and about 50kg in weight, standing on two slender hind legs. The most interesting feature of Troodons was their very large brain – six times larger than any other dinosaurs relative to their body weight. This would have most likely allowed the Troodons to be quite intelligent relative to other species, allowing it to utilise crude tools such as rolling a boulder off a cliff.

Russell believed that had the Cretaceous-Paleogene extinction event did not happen 65 million years ago (when a giant meteor struck Earth), the Troodons could have evolved in a path similar to humans, expanding their brain size and using intelligence as a tool of survival. Although its brain size was substantially lower than that of a human, he believes that through evolution, by the present its brain would be the size of a modern human’s. He also believed that evolution would have shaped the Troodons into a “dinosauroid” form, much closer to the shape of a human being. The Dinosauroid (nicknamed lizard people) would have had two fingers and a thumb, large eyes, no hair, internal genitalia (like reptiles), no breasts and a navel (the placenta is instrumental in giving birth to large-brained offspring). Their language would probably have sounded like a bird song.

Given the history of Homo sapiens and our competition and ultimate demise of similar sapient species, it is unclear whether we would have won the survival war against the Dinosauroids, or whether we would have even had the chance to evolve to our stage, as mammals rapidly filled the niche after dinosaurs were wiped out. There is much criticism of Russell’s thought experiment of the Dinosauroid being “too anthropomorphic” (too human-looking), but as suggested in the book K-PAX by Prot, perhaps the humanoid form is the most efficient natural design for an intelligent life form. Realistic or not, it is a fascinating projection of a world that could have been.

Posted in Science & Nature

Verneshot

If there is one thing we learn about dinosaurs, it is that they were wiped off the face of the Earth by an asteroid impact. Another feasible theory is that a supervolcano eruption completely destroyed the ecosystem, wiping out all life on Earth by either directly destroying them via a massive shockwave (if they were within range), or by slowly starving them as the resultant plumes of smoke would have blotted out the sun for years. But interestingly, scientists looking back over some extinction-level events of the past, discovered signs of both an asteroid strike and a volcanic eruption. This sounds to be extremely implausible, as the odds of both happening in the same era are near impossible (unless there is some extremely vengeful deity that hated the dinosaurs).

One theory that tries to explain all of this is the verneshot theory. To better understand the concept of a verneshot, imagine a cartoon character such as Yosemite Sam (the beloved red-bearded, gunslinging cowboy character on Looney Toons) shooting his gun wildly into the sky. Cartoon logic dictates that his bullets will eventually fall back on some unwary bystander. Now imagine if the Earth did the same thing, but instead of a bullet it shoots a giant piece of rock capable of causing mass extinction into the sky.

A verneshot occurs in a similar way a supervolcano erupts, where there is an incredible build-up of super hot molten rock. A supervolcano would be when this molten rock erupts as lava. In the case of a verneshot, massive amounts of carbon dioxide build up instead, leading to a pressure build-up under the crust. When the pressure becomes too much, the crust explodes, with the piece (of indeterminate size) being rocketed into space. However, the giant rock does not end up in space. Instead, it is only launched to a sub-orbital altitude, meaning it will come crashing back down to Earth due to gravity. Thus, a verneshot is when a volcanic eruption acts as a giant cannon to launch a piece of the Earth into the sky, which falls back to Earth as an asteroid-like object.