Wednesday, May 28, 2014

Making My Own Carrots 2

The carrots have been planted in a window box for a few weeks. They experienced a bit of frost the night of the recent complete lunar eclipse, but have rebounded and are now throwing up flower clusters in a few different shades.

I don't have any particular biology notes to mention here, but you can read the earlier post on the subject. I just wanted to share the recent photos.





Part 1: The initial story.

Part 3: Generation 2.

Friday, May 23, 2014

Astrobiology : Biology of Mars

New research indicates that some methanogens, Archaea which breath hydrogen and carbon dioxide while excreting methane, can survive the temperature extremes currently found on the surface of Mars. I find this to be a very interesting piece of data.

Various bacteria have been shown to survive the extreme conditions of vacuum, temperature, and radiation found in space. This second piece of interesting data indicates that bacteria can potentially be transferred from Earth to Mars, where they could survive.

Meteorites are routinely found here on Earth, including a rare few which contain gases matching those found in the atmosphere of Mars. This third piece of interesting data indicates the potential transfer of rocky material from Earth to Mars.

Together, these data indicate that living things could be found on Mars, if they had the opportunity to be transferred there at some time.

This leads us to another piece of data, referred to as the late heavy bombardment. Approximately 4 billion years ago, large rocky fragments were crashing about the inner solar system. The crater-scarred surface of the moon is the most obvious piece of evidence to this time period. Impact craters on Earth and Mars which would have been produced at the same time have been worn away by the erosional processes of the thicker atmospheres and oceans both planets held in the times soon after the bombardment ended. Some of the impacts would have been large enough to sterilize the surface of either planet, evaporating nascent oceans and scattering rocky bits all throughout the solar system. Living cells which had formed on Earth would have been carried into local space on those ejected fragments, only to come raining down later to reseed the cooling planetary surface.

The early environments of Earth and Mars were very much the same. Primordial reducing atmospheres with water oceans would have been found on both. Those rocky seeds which returned life to the sterilized surface of Earth would have also carried life to Mars. The same process would have carried Martian life to Earth, of course, but we have so little evidence from that time period that we really can't say which direction the transfer went.

A few billion years after the late heavy bombardment concluded, we evolved and started asking questions.

The core of Mars had cooled and lost its magnetic field, leading to the Martian atmosphere being stripped away by the persistent solar wind. Without a thick atmosphere, Mars cooled and dried out.  However, even now there is evidence for liquid water on Mars. There is also evidence for methane release into the atmosphere of Mars.

Given how persistent life has been found to be on our planet, living in every place it could possibly find a way to live, I strongly suspect there is life on Mars today. That life would be the last remnants of a formerly thriving biosphere, much like our own, which was descended from the simple forms of life scattered through the solar system during the late heavy bombardment.

Hopefully, we will get the opportunity to go and look while I'm still here to know about it.



References:
  1. Methanogens can survive Martian conditions.
  2. Microbes living in space.
  3. Martian meteorites.
  4. Late heavy bombardment
  5. Martian ocean.
    1. http://en.wikipedia.org/wiki/Mars_ocean_hypothesis
    2. http://www.caltech.edu/content/evidence-martian-ocean
    3. http://www.astrobio.net/news-exclusive/new-evidence-for-ancient-ocean-on-mars/
  6. Mars loss of atmosphere.
    1. http://science.time.com/2013/07/23/revealed-how-mars-lost-its-atmosphere/
  7. Association of methane and water seeps on Mars.
  8. Evidence of methane release on Mars.

Friday, May 16, 2014

A gastropod's lesson.

Guess what happens when you do an unusual project without taking before and after pictures? People might not believe your claims of having done the project.

What does this have anything to do with biology or the photo at right?

This fossil is a cast from a gastropod shell found in Ordovician-age rock found along the Mississippi river in the Twin-Cities of Minnesota. The local Ordovician-age rocks are chock full of brachiopods, but contain very few gastropods. In modern sandy ocean environments, there are very few brachiopods and gastropods are everywhere. The mix of species found within this particular ecosystem has changed dramatically over time, even though the environment is likely to be much the same now as it was back in the Ordovician.

When I found the fossil, only the broken off tip and edge of the outer whorl were evident. My new fossil-hunting-buddy didn't see these hints for what was buried within the rock and expressed skepticism when I pointed them out. My intuition, from fossil hunting periodically over the last decades, led me to be almost certain there was a snail hiding in the rock. Yesterday it was sunny and relatively warm, so I decided to go about excavating the gastropod from its tomb. I sat on the sidewalk at the back of my house and carefully chiseled away the uninteresting (to me) rock surrounding the fossil.

As is common for me, I didn't think to take a photo until the project was complete. You'll just have to (or not) believe my claim of having found and prepared this fossil myself.

When I collected this specimen, I noted another gastropod hiding in a rock which was too large for me to carry. I now have some better tools and I should be able to extract it from the boulder it calls home. If I do collect and prepare it, I'll make sure to take more photos of the process.


References