Australasian Science: Australia's authority on science since 1938

Cover Story

Cover Story

Small Fry

Zakharova_Natalia  / iStockphoto

Zakharova_Natalia / iStockphoto

By Anna Kuparinen, Asta Audzijonyte & Elizabeth Fulton

Fish are becoming smaller all over the world as oceans change and catches increase, with even small changes having great consequences for ecosystems and fisheries.

Humans are affecting oceans all around the world – through fishing, pollution and climate change. Overfishing has become a particularly burning issue over the past few decades, as many commercially exploited fish stocks have declined to historically low levels.

In addition, a new problem seems to be emerging – fish around the world are getting smaller. One reason for this decrease in size is the fishing itself, as large, usually older fish are being caught and only young and small fish are left.

Anna Kuparinen is with the University of Helsinki, and Asta Audzijonyte and Elizabeth Fulton are with CSIRO’s Wealth from Oceans Flagship.

Sex: Why Does It Have To Be So Complicated?

ltsimage/iStockphoto

ltsimage/iStockphoto

By Rob Brooks, Guest Editor

Sex. Three simple letters and a world of complication. How can something so simple, so natural and so very important be so bewilderingly complicated?

Scientists writing for or preparing to speak to the popular media are drilled on the importance of simplicity. “If you can’t explain it simply,” Albert Einstein is believed to have said, “you don’t understand it well enough”. Einstein’s own personal correspondence reveals such simplistic one-sidedness that I’m inclined to believe he didn’t understand it at all.

Professor Rob Brooks is Director of the Evolution & Ecology Research Centre at the University of New South Wales, and the author of Sex, Genes & Rock 'n' Roll: How Evolution Has Shaped the Modern World (NewSouth). He is Guest Editor of this edition of Australasian Science.

Hobbit Saga Highlights a Science in Crisis

Painting by Peter Schouten supplied by the University of Wollongong

Homo floresiensis painting by Peter Schouten supplied by the University of Wollongong

By Darren Curnoe

The latest salvo in the ongoing Homo floresiensis battle has placed the science of human evolution in deep conceptual crisis.

The 2004 announcement of Homo floresiensis – dubbed “the Hobbit” – marked the beginning of a saga all too frequent in the rarefied field of human evolution. Immediately upon its announcement, anthropologists divided along long-entrenched party lines to support or oppose the find as something novel to science. Is it a highly unusual new species? Or just a diseased modern human?

Last year saw articles clashing over whether the Liang Bua specimens were simply modern human cretins. Neither side gave any ground.

Extreme Photosynthesis: How Life on Earth Could Survive on Mars

A Chroococcidiopsis colony containing both normal and “far-red” photosynthetic c

A Chroococcidiopsis colony containing both normal and “far-red” photosynthetic cells. Credit: Dennis Nürnberg

By Elmars Krausz

The discovery of a new form of photosynthesis extends the limits where life can survive on Earth, and might provide a first step to terraforming Mars.

Earth is blessed with an abundant supply of liquid water, and is continuously bathed in light from the Sun. Nature has taken advantage of these conditions to evolve more than a trillion life forms.

Life needs chemical energy to drive its machinery along. Essentially, it requires an oxidisable chemical as a source of electrons. Early life forms exploited a number of processes, but in the end the “voltage” of these sources of electrons and the availability of the relevant chemicals were limited. So nature took another tack.

Brain Circuits that Control Drinking

Credit: KariDesign

Credit: KariDesign

By Philip Ryan

Cutting-edge genetic technology has revealed how the “love hormone” oxytocin protects us from drinking too much, and could lead to a better understanding of the brain circuitry underlying mental illnesses.

Gene Drives: A Way to Genetically Engineer Populations

Credit: Mopic/Adobe

Credit: Mopic/Adobe

By Charles Robin

Gene drives occur when a bias in the mechanism of inheritance spreads particular genetic variants through a population. Developments in gene-editing technology now make it possible to construct gene drives that address problems in health, agriculture and conservation.

The concept of gene drives has been around for decades. They occur in natural systems, and scientists have imagined how they might be put to use. Recent advances in gene-editing technology means that “synthetic gene drives” can now be created, and the scope of applications is broad.

It’s time to consider the hazards as well as the opportunities this technology brings, and weigh up the benefits versus the risks. There are also ethical concerns, and scientists must be careful not to leave the community behind.

Genomic Testing as a Lifetime Health Resource?

Credit: mrallen/adobe

Credit: mrallen/adobe

By Ainsley Newson & David Amor

If lives could be saved by being “forewarned” by a genomic test, should we perform genomic testing of all babies at birth?

Rapid developments in genomic testing methods have made the sequencing of a person’s DNA faster and cheaper than ever before. The latest gene sequencing machines can sequence all 20,000 human genes in less than 3 days at a cost of less than $2000 per person. This is comparable to the cost of testing just one gene using slightly older sequencing machines.

But what are the scientific and ethical issues involved in the use of genomic information as a “lifetime health resource”? Are we ready for the wide application of genome testing in people who are otherwise well?

Fertility in the 21st Century

Credit: Clicknique/iStockphoto

Credit: Clicknique/iStockphoto

By Rebecca Robker & Eileen McLaughlin

Fertility is a diverse field of research that encompasses male and female infertility, pregnancy complications, and environmental and lifestyle influences that can affect the reproductive health not only of future generations but also our native wildlife.

In Australia today, one in six couples experiences infertility and typically one child in every classroom was conceived by medically assisted reproduction technologies like IVF. Conversely, an estimated 25% of all pregnancies are electively terminated. Meanwhile, the search for improved contraceptives continues, including contraceptives for men. These prevalent yet polar opposite fertility issues illustrate that reproduction sits squarely at the forefront of health challenges in Australia.

Survival of the Sexiest

iordani/Adobe

Credit: iordani/Adobe

By Barnaby Dixson & Monica Awasthy

“Survival of the fittest” never applied to beards, so why did they evolve and what role do they play in mate selection in modern society?

Facial hair has seen a resurgence in popularity in recent years. Beards are definitely “in”, and men go to great lengths to groom and maintain them. In fact, the male grooming industry is estimated at US$15 billion globally.

But why do beards exist in the first place, and how do biology and culture interplay to shape their meaning as an animal signal?

The Beard as a Badge of Status

Rock around the Cosmic Clock

Credit: NASA/JPL

Credit: NASA/JPL

By Paul Brook

Astronomers examine pulsar emissions for signs of gravitational waves, but now they believe that an asteroid may have affected the accuracy of one of these “cosmic clocks”.

When a massive star reaches the end of its life, a spectacular supernova explosion occurs and most material from the star is flung off into space at speeds of around 10,000 km/s. Since this material has been thrown far and wide, the core of the star is left exposed. This stellar core will now begin a new life as one of two exotic and fascinating objects: either a black hole or a neutron star.