A (Cricket) Song Long Forgotten

Along with most soft tissue, color, and a host of other features of prehistoric life, the sounds those long-gone creatures made are lost through the depth of time. While we make inferences about the sounds made by Parasaurolophus, Tyrannosaurus rex, the earliest birds, and the other animals living at the time, those projections are just just guesses, based on an approximation of acoustic and air flow properties. If those creatures had vocal chords, or any soft-tissue mechanism for creating sound, then we today have no way of recreating those noises.

A singing modern cricket
From what-when-how

However, there are some animals that don't use soft tissue and complex skull structure to create sound. Modern crickets, katydids, and other insects in the Orthoptera order create sound by running a row of "teeth" on one wing across the other, similar to a violinist running a bow across the strings. These fine details, however, very rarely preserve in the fossil record. It was not until a very detailed specimen, from North China, was discovered that Dr Fernando Montealegre-Zapata and Professor Daniel Robert, experts in biomechanics, were able to determine how ancient crickets made noise, and what they would have sounded like. This 165 million-year-old cricket had similar stridulating organs (the mechanism used to make sound) to modern species, something that's never been seen before in a fossil. The team built a reconstruction of that structure, and compared it to many modern species, to determine what it sounded like. In fact, the fossil was so detailed that they could fully recreate the song of this species, named Archaboilus musicus. You can listen to it here.


Unless the laws of physics suddenly allow us to build a time machine to the past, we will never know exactly how the Jurassic landscape sounded. The discovery of A. musicus, and hopefully more insects like it, along with understanding the sounds made by amphibians, mammals, dinosaurs, and reptiles, based on what information we can glean from the fossils and what we know of modern creatures, will help us to slowly piece together a more dynamic landscape of the past, engaging not just the eyes, but the ears as well.

Source: Science Daily- Fossil cricket reveals Jurassic love song
Wired - 165-Million-Year-Old Cricket Song Comes Back to Life

The Extreme Tardigrade

Most extremophiles are bacteria, living in places like the deep-sea hydrothermal vents, sulfuric hot pools, oxygenless layers in the ocean, and other environments that are deadly to every other form of life. But there are a few extremophile animals, such as the tardigrade.

>

Impressed yet? These invertebrates are some of my favorite living animals, and are a fascinating study in how evolution works. We still barely understand extremophiles of this sort, and there's a lot more research to be done. If you are interested in learning more, there are some resources below the break.

The Census of Marine Life

Around 70% of Earth's surface is covered in water. On average, this water -the ocean- is about 14,000 ft (2.65 miles, 4.267 km) deep.^(source) The ocean is also one of the least well-explored places on our planet. It's practically an alien world. Recently, numerous scientists, including marine biologists, oceanographers, geologists, and others, have been working to rectify this gap in our knowledge of the planet. One exciting new step they've taken is the new Census of Marine Life.

The scale of this project was fantastic: over 2700 scientists, from more than 80 different countries, publishing 2600 papers over the course of a decade, spending countless hours on field expeditions and lab analysis. The recently published Census shows an impressive scale of oceanic diversity: 120,000 species, from plankton to whales and everything in between, were observed through the course of this project. Multiple maps were created to show where different organisms live.

Still, as impressive and large scale as this census of the oceans is, it's far from comprehensive. On the maps of organism ranges, there are places that show where the sea has yet to be explored. Dr. Ian Poiner, chair of the Census Steering Committee, claims that there are still at least 3/4 of a million species in our oceans that remain undiscovered. This is just a start to understanding our fellow creatures beneath the waves. There's a lot yet to learn. Space may be the final frontier, but the ocean holds tantilizing opportunities for exploration as well.

For more information on the Marine Life Census, and to explore the OBIS (Ocean Biogeographic Information System) database, visit the Census of Marine Life.

Source: Science Daily: First Census of Marine Life shows ocean life is richer, more connected, more altered than expected

Algae and Developing Genders

An interesting question in evolution has always been how the two genders evolved. Most unicellular animals don't have district genders; they can reproduce both sexually and asexually. Two little single celled algae look pretty much the same, right down to the gametes that combine to create a new algal cell. Most multicellular animals, however, can be classified pretty easily as either male or female. The majority of these are only able to reproduce sexually (there are some species of reptile that get around this, but that's a discussion for another post). Plants, too, have a distinct male and female. Considering sexual dimorphism -the development of a distinct male and female in a species- is a trait uncommon in single cell organisms and common in multicellular ones, there must have been some evolutionary change which made different genders far more beneficial. Unfortunately, neither single cell organisms nor genetic material preserve in the fossil record, so we cannot look there for answers.

Volvox carteri

A comparison of two closely related algal species has given researchers some interesting clues on this evolutionary gap. Volvox carteri is a multicellular green algae, and its cousin, Chlamydomonas reinhardtii, is single celled. Their genomes are pretty much identical, with one giant exception. In the area of the genetic code that serves as the algal version of X and Y chromosomes, Volvox had some of the same genes and Chlamydomonas, along with a wide variety more. In fact, this section is five times larger in Volvox. This was a huge surprise. In the past, researchers had though that the "sex chromosomes," X and Y, had developed as a section of the genome deteriorated. These algae suggest that the opposite is true: that, for whatever reason, the bits of DNA involved with gender and reproduction can change and diversify very quickly.

There is a lot more study that has to be done to map out any sort of evolutionary path for this change. The team is looking more closely at the "new" genes in Volvox, as well as comparing both species to a third, Gonium, which is an intermediate between Volvox and Chlamydomonas. It's one of the first breakthroughs in determining how sexual dimorphism originally around. It will take time, but it's a very interesting first step to solving this evolutionary mystery.

Source: Science Daily- Lessons from the Pond: Clues from green algae on the origin of males and females

A Life Without Air

When you think of an organism, you probably think of some type of animal. These creatures need one particular element to gain energy and survive: oxygen. Most of the sugars and fats that are burned within our bodies, and those materials are made with oxygen. There are some bacteria which can survive anaerobically - without air - but certainly no animals that can, right?

An anaerobic animal,
of the group Loricifera
Image Source: Science Daily

Well... not quite. Deep in the Mediterranean Sea live little multicellular creatures that have never come across oxygen. More than that, they are submersed in sulphides, which are usually toxic to animals. Researchers had previously found some multicellular organisms in this and other deep hypersaline anoxic basics, but had assumed that they had died and floated down into this harsh environment. Not the case with these little Loricifera, however. Tests showed that not only where the animals alive, they were thriving and reproducing.

So, how do they do it? Most animals, including humans, need to metabolize oxygen using mitochondria. This process produces energy. For a short period of time, individual cells can produce enough energy to survive without oxygen, but not for any extended length of time. These creatures live in a complete absence of oxygen. The researches used an electron microscope to see what the Loricifera used to produce energy. Instead of the aerobic mitochondria common in pretty much every other animal, they have hydrogenosomes, similar to those found in bacteria that also inhabit anaerobic environments. In other words, instead of using oxygen dissolved in the water to survive, they use the hydrogen dissolved in the water.

This finding is really exciting. Before this, scientists had guessed that there must have been some form of animal that lived without oxygen, way back in the early history of life (550 to 600 million years ago). This gives us more clues about the nature of these creatures. It also opens the door to more research in other anoxic part of the ocean. It seems unlikely that the Loricifera species is the only animal that thrives in this environment, now that we've discovered it is possible.

Source: Science Daily- First Animals to Live without Oxygen Discovered

Eggshell DNA

One of the problems with studying extinct species is that... well, they're extinct. With fossils, especially, it is difficult to learn much about a creature besides what its skeleton tells us. This is why the idea of extracting fossil DNA is so exciting. With strands of fairly intact DNA, scientists could analyze different genes in an extinct creature, giving some clue to things like coloration, evolutionary lineage, etc. If there was enough really well preserved DNA, it could even be possible to bring extinct species back to life.

Elephant Bird Skeleton and Egg

There's a major problem with extracting DNA from fossils, though. DNA is an extremely fragile molecule; it does not take long for it to degrade once a creature dies. Even the best preserved fossil bones have partial DNA at best. While this does prevent a lot of ethical questions, like whether we should bring extinct creatures back if we could, it makes understanding those creatures much more challenging.

A recent article published in the Royal Society journal offers a new possibility in recovering fossil DNA, however. Scientists looked, not to bones, but to eggshell to try and extract DNA. They successfully recovered genetic material from the eggshell of Aepyomis, the elephant bird of Madagascar, for the first time. They were also able to get DNA from New Zealand duck and moa eggshells, and Australian emu and owl eggshells, the oldest of which was 19,000 years old. Because eggshells are pretty resistant to decomposition, it makes sense that they would preserve the DNA better than bone.

This is an exciting step towards perhaps getting a fuller understanding of extinct species. It's still no where near dinosaurs, but it provides a new way to look. It will be interesting to see where this sort of research takes the studies of zoology and paleontology in the future.

Source: Discovery Channel- Fossilized Eggshells Yield DNA

Sea Slug Going Green

It's pretty common knowledge that plants use chlorophyll to turn sunlight into energy. It's what gives them their green color. Animals typically don't have chlorophyll, and so need to consume plants or other animals to gain the energy necessary to survive. (A few single cell plankton produce chlorophyll, but they barely meet the definition of an animal) A newly discovered sea slug has learned how to cut out the middleman. According to Sidney Pierce, the biologist who discovered these creatures, they can steal the chloroplasts from algae, as well as the genetic material needed to make chlorophyll.

This is possibly one of the coolest discoveries I've seen in marine biology, along with the tool-using octopus. Scientists knew that organisms could swap genetic material; bacteria do it all the time. However, the fact that this sea slug can steal the genes to make chlorophyll so successfully is remarkable. Baby sea slugs are born with the ability to produce chlorophyll, although not the ability to produce chloroplast that allow them to use the chlorophyll. It's a very neat evolutionary adaptation. The sea slugs have integrated one of the traits that make plants so successful. How, scientists have no idea. There is no known mechanism that lets the DNA transfer like this. It's another area to be further researched.

Source: Live Science- Surprising Sea Slug is Half-Plant, Half-Animal

Mobile Home for an Octopus

Tool usage was once considered to be one of the key features separating us from other animals. However, recently we have discovered that most primates, some birds, and a few other mammals use tools as well. And now, for the first time, we have found an invertebrate using tools. The best way to describe this is simply to watch:

These octopi, Amphioctopus marginatus, are using the coconut shells are a protective home. Now, you might think that this is similar to what hermit crabs do. After all, they are also an invertebrate which uses discarded shells to protect themselves. However, a hermit crab's shell is more like a hat for us: just put it on and forget about it. The coconut shells of these octopi are much different. As you could see in the video above, the creatures hold the shells under their bodies and "run" along the sea floor. They also go through an elaborate process to put two coconut halves together, completely encasing themselves. Far more effort than simply putting on a shell and forgetting about it.

The adaptations that life on this planet have come up with are pretty incredible. We've just scratched the surface in learning about our fellow creatures on this planet. More research is certain to reveal even more amazing behaviors.

For more information, visit National Geographic.