Chemosynthetic Autotrophs

When life arose on Earth about 4 billion years ago, the first types of cells to evolve were prokaryotic cells. For approximately 2 billion years, prokaryotic-type cells were the only form of life on Earth. The oldest known sedimentary rocks found in Greenland are about 3.8 billion years old. The oldest known fossils are prokaryotic cells, 3.5 billion years in age, found in Western Australia and South Africa. The nature of these fossils, and the chemical composition of the rocks in which they are found, indicates that these first cells made use of simple chemical reactions to produce energy for their metabolism and growth. Eukaryotic cells evolved into being between 1.5 and 2 billion years ago. Eukaryotic cells appear to have arisen from prokaryotic cells, specifically out of the archaea. Indeed, there are many similarities in molecular biology of contemporary archaea and eukaryotes. However, the origin of the eukaryotic organelles, specifically chloroplasts and mitochondria, is explained by evolutionary associations between primitive nucleated cells and certain respiratory and photosynthetic bacteria, which led to the development of these organelles and the associated explosion of eukaryotic diversity. Today Prokaryotes

According to Margulis, the pre-eukaryotic cell engulfed an aerobic bacterium, but rather than digest and kill the bacterium, a symbiotic relationship was born. This relationship, the aerobic bacterium provided energy through ATP and the eukaryotic cell provided an environment to live while protecting the new symbiont from harm in environmental factors such as oxygen. Because almost all living eukaryotes have a mitochondria, it is safe to assume that this event happened before plants and animals split in the evolutionary lineage.After this first evolutionary leap came a

These chemicals were possibly delivered by large comets and asteroids flying throughout the solar system billions of years ago. Organics, compounds that contain carbon, oxygen, nitrogen, and hydrogen, are very essential in the search of possible life on other planets. The second key ingredient includes a liquid. Like water on Earth, there needs to be a source of liquid that would allow the compounds to mix and interact. Danny Faulkner, Ph.D. says “as the universal solvent, water is absolutely essential for life, making up the majority of the mass of many organisms” (icr.org). Finally, the third key ingredient to finding life on other planets is an energy source. A source of energy, like the sun to Earth, powers these chemical reactions to make life

To maintain life, organisms must be able to convert energy from one form to another. For example, in the process of photosynthesis, algae, plants, and photosynthetic prokaryotes use the energy from sunlight to convert carbon dioxide and water to glucose and oxygen (a waste product).

B. Chemoheterotroph- all protozoa, fungi, and animals and most bacteria use chemicals such as glucose for carbon and energy. Their energy and carbon is organic compounds.

Early earth was dominated with carbon dioxide and hydrogen sulfide. Hydrogen sulfide are invisble gas that were poisonous. We think this is when life first took hold. Penny Boston and Diana Northern investigate how life can survived here. They went to a cave, Cueva day Pl lose which was filled with hydrogen sulfide. Life is thriving inside the cave. Single cell bacterias snot tights were here. Bacteria are common organism, grow adapt and reproduce. Many bacteria were found and they survive from the hydrogen sulfide. If they can find life here, then life can be formed in early earth.

These biologists are particularly interested in the ancient microbes that are laying dormant in Naica, Mexico. For these life forms to survive, it appears that they were able to exist by living off on minerals such as manganese and iron.

There were two types of bacteria: sulfur-eating bacteria, and cyanobacteria. Sulfur eaters were the predominate kind of bacteria, but died out when cyanobacteria started photosynthesizing and producing oxygen. Oxygen is lethal to sulfur-eating bacteria. This was called the great oxygenation. The sugars produced by photosynthesis would be the base of the modern food chain. The origin of archaea is unknown. Eukaryotes came into play around 1.5 billion years ago.

Prokaryotes are ubiquitous, successfully adapting to diverse environments as well as developing symbiotic relationships with host organisms (Lengeler, Drews, & Schlegel, 1999). Prokaryotes may have both autotrophic and heterotrophic characteristics. A cyanobacteria is photosynthetic, commonly called blue-green algae, and may produce toxins (Crayton, 1993). Bacteria are most commonly associated in the general

Microscopic  organisms  known  as  cyanobacteria are  interesting  for  the  following  reasons: [SELECT  ALL  THAT  APPLY] Select  one  or  more: A.  Oxygen  produced  by  their  photosynthesis is  thought  to  be  responsible  for  the  "great oxygenation  event"  about  2.3  billion  years ago.   B.  The  methane  they  produce  is  a greenhouse  gas  that  could  have  helped warm  the  early  Earth,  helping  to  resolve  the Early-­faint-­Sun  paradox. C.  The  chloroplasts  that  carry  out photosynthesis  in  green  plants  are evolutionary  descendents  of  early cyanobacteria.   D.  They  are  known  to  be  the  earliest  forms of  life  on  Earth.

When oxygen and nitrogen combine in water, it forms nitrate, which is an essential chemical for eukaryotic algae; however, cyanobacteria do not need nitrate for their survival, contrary, they use elemental nitrogen. This way, even after the evolution of true algae, even though in fewer quantity, cyanobacteria remained widespread, and oxygen was accumulated.

Autotrophs and heterotrophs are two different organisms that have distinct traits that differentiate them from one another. Autotrophs produce their own food for their energy while heterotrophs are dependent on other organisms for their food, due to this autotrophs are known as primary sources on the food chain level while heterotrophs are the secondary and tertiary sources due to their reliance on autotrophs. Autotrophs are separated in two groups, photoautotrophs and chemoautotrophs, an example of a photoautotroph is algae, photoautotrophs collect their energy from sunlight, carbon dioxide, and water. Iron Bacteria is an example of a chemoautotroph, chemoautotrophs derive their energy from oxidation, which is the process of gaining oxygen.

eutropha has the ability to grow autotrophically, to create its own food from inorganic substances, using nitrogenous waste such as urea in a hydrogen rich environment (Ammann and Reed 1967). This makes R. eutropha an ideal organism to use in an environment like space, which does not readily allow growth. As shown by Foster and Litchfield (1964) electrolysis of water has been considered as a source of oxygen for use in space. The resulting waste surplus of hydrogen can be used by R. eutropha to produce a food source, protein. The bacteria’s use of other waste products such as carbon dioxide and urea would be highly beneficial as a means of disposing of waste efficiently and

Life on Earth is dependent entirely on the energy from the Sun, not only to keep the planet at a suitable temperature but also to provide the energy required to sustain life. The energy of the Sun, in the form of photons, is actively captured by chlorophyll and related pigments present in photosynthetic organisms, like plants and algae. This captured energy is used to convert carbon dioxide into complex energy-rich molecules that can be used by themselves

It is common in the field of microbiology for scientist to need to quantify bacteria. A way to do this is via the production of CO2. Carbon dioxide can be produced as a byproduct of cells performing regular respiration and decomposition activities. For microbes to live and grow successfully they need an adequate source of carbon. The microbes can either produce this source themselves making them autotrophic or receive the carbon from and outside source making them heterotrophic. Without a proper carbon source microbes like bacteria would not be able to function properly and produce several vital components for life including lipids, DNA, sugar, and proteins. All carbon sources are not created equally, not all of them can be used in the same chemical pathway. Glycolysis requires the use of glucose whereas the citric acid cycle can use citrate directly. Lactose is an extremely complex sugar and must be broken down a number of times before it is usable in the process of glycolysis. Succinate and acetate just like citrate can enter directly in to the citric acid cycle or it can also be converted into Acetyl-CoA. Due to the nature of these cycles and how the carbon gets broken down some carbon sources are naturally better than others. Glucose is the best theoretical source with the ability to produce around four CO2 molecules. The second best would be lactose that could produce the same amount of carbon dioxide but at a slower rate. This is followed by citrate which