evidence for evolution of LUCA near hydrothermal vents Flashcards
How can LUCA’s genetic make-up be investigated?
By studying genes that are found widely in bacteria and archaea today. These genes are believed to have been inherited from LUCA, the last universal common ancestor.
What does a shared gene between bacteria and archaea suggest about LUCA?
If a gene is shared by both, it suggests LUCA had that gene, as it was inherited from a common ancestor.
What did researchers identify as genes in LUCA’s genome?
355 protein families likely found in LUCA’s genome, including genes for anaerobic metabolism and for fixing carbon dioxide and nitrogen.
What does the presence of genes for anaerobic metabolism and fixing gases suggest about LUCA’s environment?
LUCA likely lived in an environment rich in hydrogen, iron, and carbon dioxide, possibly around hydrothermal vents.
What are hydrothermal vents?
Hydrothermal vents are cracks in the Earth’s surface where hot water emerges, carrying reduced chemicals like iron sulphide.
Why are white smokers (alkaline hydrothermal vents) important for the origin of life?
They provide high temperatures (60–90°C) and chemical compounds like hydrogen, methane, ammonia, and sulphides, which could have provided the energy needed to create early life.
What compounds were likely abundant at hydrothermal vents to support early life?
Hydrogen, methane, ammonia, sulphides, and carbon dioxide, which are important for assembling carbon compounds into polymers.
Why were high concentrations of carbon dioxide important for LUCA?
High carbon dioxide levels would have been necessary for carbon fixation processes in early life, allowing cells to convert inorganic carbon into usable organic forms.
What does the hydrothermal vent hypothesis suggest about the origin of LUCA?
The hydrothermal vent hypothesis suggests that LUCA likely evolved in or around hydrothermal vents, where the right conditions for early metabolism and the synthesis of complex molecules existed.
