A recent study from the Center for Ecology and Conservation at the University of Exeter in the UK has found out that being a highly attractive species can increase the risk of its extinction.

The study further explains that the differences in appearance between males and females of the same species, which is called sexual dimorphism, can actually make an animal go extinct, instead of ensuring survival by making them more attractive mates.

The researchers concluded that there is up to 10 times more chance for species with greater sexual or physical differences to go extinct.

However, Darwin's theory of survival of the fittest explains that animals choose their partners based on its sex-specific viability.

Sexual dimorphism can bring about differences in color, shape, size, and structure in some animals and plants.

The best example of sexual dimorphism can be seen in peacocks. The males have elaborate tails with bright colors, while the females are dull and have shorter feathers. The bigger the tail of the male peacock, the more attractive it becomes to the peahen.

Other research has found that huge horns and bone frills in some dinosaurs were meant to make them more attractive to their mates, rather than being used in fights with other males.

The current study shows that developing pretty features might come at a huge cost to some species.

"The evolutionary costs of such traits help to enforce the honesty of the associated displays, but can also reduce the fitness of populations in general and thereby increase the risk of [the]population," the researchers of University wrote, according to Tech Times.

The research was published in the journal Nature this week.

The researchers studied fossils of 93 species of ostracods, which are also known as seed shrimps. These shrimps lived 84 million years ago. In the study, the team looked at their physical traits and the approximate time of extinction.

They concluded that male ostracods, also known as seed shrimp, evolved heavily in terms of their appearance to the point that they missed out on other survival factors.

Jonathan Payne, a geological sciences professor at Stanford University also pointed out that this theory might be only applicable to ostracods and not to human beings and other animals. Also, the researchers said that the ostracods' size and their ability to regulate body temperature were major hurdles for the study. </s> Close

Species that are highly attractive or different have higher risks of extinction compared to those that blend similarly with the rest, a new study finds.

A research published this week in the journal Nature reported that sexual selection in ancient animals determined which species will survive or go extinct.

Peacocks, for example, have evolved with big colorful tails. The bigger their tails, the more attractive they become to the opposite sex.

Also, paleontologists ruled that the huge horns and bone frills common in triceratops were meant to woo potential mates and not necessarily to defend or attack an enemy.

Sexual Dimorphism

David Punzalan and David Hosken, researchers at the Center for Ecology and Conservation at the University of Exeter in the UK, have defined sexual dimorphism as the obvious differences in male and female physiology, behavior, and morphology.

In Darwin's theory of survival of the fittest, sexual dimorphism has become closely related to sexual selection, a phenomenon in which animals choose their partners based on its sex-specific viability.

There are two contrasting evolution models related to sexual selection. One suggests that dimorphism actually helps species adapt to their environment; thus, making them less likely to become extinct. The other states that exaggerated physical traits make them a target for predators.

Risk Of Extinction

As a result, species with greater sexual or physical differences went extinct for up to 10 times compared to species with typical appearances.

"The evolutionary costs of such traits help to enforce the honesty of the associated displays, but can also reduce the fitness of populations in general and thereby increase the risk of [the] population," the researchers wrote.

Fossils of 93 species of ostracods that existed some 84 million years ago during the Late Cretaceous period were analyzed based on their physical traits and the approximate time of extinction.

Researchers found that male ostracods, also known as seed shrimp, evolved heavily in terms of their appearance to the point that they missed on other survival factors.

The research "provides a strong indication, and the first good documentation from the fossil record, that sexual dimorphism tends to increase extinction risk," said Jonathan Payne, a geological sciences professor at Stanford University.

However, Payne further said that information from the fossilized ostracods may not necessarily apply to human beings and other animals. Researchers cited the ostracods' size and their ability to regulate body temperature in water as major limitations of the study.

ⓒ 2018 TECHTIMES.com All rights reserved. Do not reproduce without permission. </s> When plant and animal species go extinct, it's usually a clear sign that humans have messed up. We've over-hunted, destroyed habitats, polluted waterways, and altered the climate by burning fossil fuels, wiping species off the planet for good.

We tend to study extinctions to understand just how much we have disrupted the planet's ecosystems. But in a new scientific study published on Monday, scientists said we're not paying nearly enough attention to the "prelude" to global extinction — as in, the dwindling population sizes and ranges of existing species that can be a warning sign of a bigger extinction event to come.

SEE ALSO: 800 wildlife species at risk from Trump's 'beautiful' border wall

As with extinctions, these declines have serious consequences for the natural systems we all depend on for clean air and water, food, and shelter.

"This is the case of a biological annihilation occurring globally, even if the species these populations belong to are still present somewhere on Earth," Rodolfo Dirzo, the study's co-author and a biology professor at the Stanford Woods Institute for the Environment, said in a press release.

For their analysis, published in the Proceedings of the National Academy of Sciences, Dirzo and his colleagues mapped the ranges of 27,600 species of birds, amphibians, mammals, and reptiles worldwide. The sample represents nearly half of all known land-based vertebrate species.

Scientists estimated that, of these species, nearly one-third of the vertebrates are declining in population size and range. Shrinking ranges mean animals — especially migratory species — have less room to hunt, breed, and hunker down.

As ranges decline, population numbers also dwindle, pushing a species closer to the edge of extinction.

Tropical regions saw the greatest number of decreasing species, particularly in south and southeast Asia. In Thailand and Myanmar, for instance, illegal hunting and logging of rosewood trees has drastically reduced the population of Indochinese tigers. Indonesia's Sumatran orangutan has lost roughly 60 percent of its habitat as farmers burn and drain swamp forests to produce palm oil.

Temperate regions had similar or higher proportions of decreasing species compared to tropical regions, according to the study.

Dirzo and his co-authors also looked at 177 well-analyzed mammal species and examined population losses between 1990 and 2015. Within this group, all have lost 30 percent or more of their geographic ranges. Some had been hit especially hard: more than 40 percent of the species have lost over 80 percent of their ranges. "It is a prelude to the disappearance of many more species and the decline of natural systems that make civilization possible," Gerardo Ceballos, the study's lead author and an ecology professor at the National Autonomous University of Mexico, said in the press release. Monday's research adds to the broader scientific debate about the " " — which is likely happening to the planet right now, and might be the biggest mass extinction since the dinosaurs disappeared 66 million years ago. During Earth's 4.5-billion-year history, five major extinction events have wiped out nearly all the species on the planet, the geological record shows. Asteroid strikes, volcanic eruptions, and natural climate shifts were likely to blame for those past events. However, this sixth mass die-off is largely due to human activities, such as population growth, habitat destruction, pollution, and climate change. In their paper, Dirzo, Ceballos, and Stanford professor Paul Ehrlich suggested that billions of animal populations that once roamed the Earth are gone. A separate 2016 study by World Wildlife Fund said global populations of vertebrates have declined by 58 percent between 1970 and 2012. The authors of Monday's paper said their research shows "Earth's sixth mass extinction has proceeded further than most assume." They added that the steep population declines amount to a "massive erosion of the greatest biological diversity" in Earth's history.
A study in Nature shows species which are visually unusual or attractive go extinct at higher rates.