The first organism, the common ancestor to all life on Earth, is now thought to have had no nucleus. It was the small single-celled ancestors of both bacteria and archaea, which have spread all over Earth and evolved into many successful varieties, including extremeophiles. (It’s humbling to realize that our health and well-being is dependent on our personal gut biome, which is composed of these critters.)
Archaea and bacteria have different fats in their cell membrane, but their common ancestor had both types of fat, so it probably leaked. This weakened the common ancestor. It disappeared eventually, giving way to those who chose just one fat and became archaea. Bacteria chose another fat, and both have done well to this day. Now bacteria fill every niche on this Earth. It is a very successful being. However, recent studies have shot down the double fat argument.
Bacterial strains have been created in the lab that have 30% archaeal lipid and 91% bacterial lipid, but they don’t leak–shooting down the above theory for the ancestor’s demise. The puzzle remains. What was the first organism on Earth and why didn’t it survive until now?
Why do we care? Because we don’t understand how life got its very first start here on Earth, hence we don’t know how to look for signs of life or its potential on exoplanets.
What does survive here on Earth now–to give an example of life’s amazing extreme possibilities–is a weird critter in the hot, acid blue-green lake called Laguna Caliente in Costa Rica. The critter Acidiphilium is alone in this lake with floating clumps of sulfur (See
EOSbuza060118). The lake is considered to be just barely habitable. It resembles what we suppose might be like ancient Martian terrain. Sulfuric and hydrochloric acids are in the air, and the water’s pH is 0.29, 10 times more acidic than our stomachs.
Finding life in such extreme places on Earth gives us hope that life might have evolved on exoplanets like 55 Cancri, which is tidally locked but may have lava lakes on its hot side and hints of an atmosphere like Earth’s. The planet’s density is also like Earth’s, so it is probably
rocky. The dark side is not as cool as it might be. Its sunny side keeps it too hot to maintain liquid water. Since it is carbon-rich, its center could contain diamond.
Ross 128b is a rocky, temperate planet, 1.3 Earth’s mass and only eleven light-years away from us. Its year is only 10 days long, so it is probably tidally locked and may be a life denier. Hopefully, Ross 128b will be a prime target for TESS’s atmospheric studies.
Other exoplanets to watch are those with a stratosphere, where the temperature increases with higher altitudes. Proxima b is another exoplanet to watch, since it is the right size and has an ok temperature for life. Kepler-90 has the same number of planets as our sun, if that
counts for anything. Twenty-nine exoplanets less than twice Earth’s size have been found by Kepler to be in their star’s habitable zone. The list of exoplanets with hope for life goes on and will soon expand with atmospheric data as TESS begins work.
Author of The Archives of Varok
The View Beyond Earth (Book 1.)
The Webs of Varok (Book 2.)
Nautilus Silver Award 2013 YA
ForeWord IBPA finalist 2012 adult SF
The Alien Effect (Book 3.)
An Alien’s Quest (Book 4. Released Nov.21, 2016)
Excerpts, Synopses, Reviews, On Writing, Characters and More-
Reviews of significant books- www.goodreads.com/Cary_Neeper
How the Hen House Turns- www.ladailypost.com
Complexity, Bio, Bibliography and Links- caryneeper.com
Astrobiology- astronaut.com search:Who’s Out There