BIOL113 M2 L1

• What evidence suggests that prokaryotic life evolved between 3.5 and 3.85 Billion Years Ago (BYA)?

  Stromatolites, fossilised mats of ancient prokaryotes have been discovered that are 3.85 BYA. ,

  Isotopically light carbon that appears to have gone through biological processes appears to be 3.85 BYA. , Cell like structures that appear to be prokaryotic cells appear in the fossil record approximately 3.5 BYA. 
• What does a reducing atmosphere mean?

  Oxidation is prevented due to the absense of oxygen and other oxidating gases or vapours. The first atmosphere had lots of water vapour and volcanic eruptions were responsible for putting several gases into the air. These gases; methane, Co2, ammonia, hydrogen sulfide and hydrogen, were highly reductive, and would have been readily oxidized if there was oxygen around.
• how old is the earth ?

  ~5 Billion years old
• Where did abiotic synthesis of organic molecules happen?

  1. Deep in the oceans at hydrothermal vents
  2. Rocky pools or hot springs
  3. Water and land interface
  4. Sandy pourous clays
  5. Outerspace (comets, meteorites)
• what does abiotic mean ?

  Non-living
• what does biotic mean?

  living
• how would sandy pourous clays synthesize organic molecules ?

  Has potential to attract things to it, acting as a binding agent for non-clay components.
• How can hydrothermal vents synthesise organic molecules ?

  Deep-sea vents provided stability amid meteorite strikes. These vents released gases and housed iron sulphides, which can facilitate chemical reactions, potentially sparking the formation of organic molecules like acetate, which could have influenced the development of modern enzymes.
• how could meteorites synthesise organic molecules?

  Basic chemicals can change into organic molecules with energy, which might come from lightning or chemical gradients. In a 2014 Czech study, adenine, guanine, cytosine, and uracil – crucial for RNA and DNA – formed when formamide and clay were hit with strong laser pulses, like meteorite impacts on early Earth. This suggests formamide, with its essential elements, might have been a starting point for many organic molecules, indicating that meteorite impacts could have jumpstarted life on Earth.
• Where did the energy for abiotic syntheis of organic molceules come from ?

  UV light and lightning
• How did micro-organisms transform the planet?

  Early microorganisms like cyanobacteria performed photosynthesis, which involved absorbing carbon dioxide and releasing oxygen, contributing to the establishment of a stable oxygen-rich atmosphere. Additionally, microbial activity in soil and oceans influenced the cycling of gases like nitrogen and carbon, regulating atmospheric composition and maintaining environmental balance.
• Outline at least one reason that microorganisms are extremely diverse

  Microbes inhabit diverse habitats, from extreme environments like deep-sea vents to soil and human bodies, leading to specialisation and niche adaptation.
• Describe three features of a population that experience Darwinian evolution

  Multiplication, an organism needs a way to replicate itself and the offspring of this organism must resemble it in some way (hereditary). For a population to be successful it needs to have variance, this strengthens the populations’ ability to survive diseases or random changes in the environment.  
• whats the difference between something that is alive and something that is not alive ?

  Living things are organized, grow, reproduce, respond to their environment, maintain stability, and undergo metabolism. Non-living things lack these characteristics. For instance, fire and salt crystals do not grow, reproduce, respond to stimuli, maintain stability, or undergo metabolism, so they are considered non-living.