LAST UNIVERSAL COMMON ANCESTOR OF ALL ORGANISMS Meaning and
Definition
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The last universal common ancestor (LUCA) of all organisms refers to the hypothetical organism from which all living organisms on Earth are descended. According to evolutionary theory, LUCA is considered to be the earliest known living being from which all life forms originated. It represents the most recent organism from which all organisms have diverged through various evolutionary processes over millions of years.
The concept of LUCA suggests that at some point in Earth's history, there existed a universal ancestor that gave rise to the three major domains of life: bacteria, archaea, and eukaryotes. LUCA is thought to have emerged approximately 3.5 to 4 billion years ago during the early stages of life on Earth.
Although the precise characteristics of LUCA remain uncertain, it is believed to have been a simple cellular organism that thrived in a primordial environment, potentially in deep-sea hydrothermal vents or on the ocean floor. LUCA likely possessed minimal genetic information and basic metabolic capabilities, such as the ability to process simple organic molecules. Over time, through genetic mutations and the acquisition of new genetic material, LUCA's descendants eventually gave rise to the diverse array of organisms that inhabit the planet today.
While LUCA itself cannot be directly observed or studied, its existence is inferred through comparative genomics and evolutionary analysis. Unraveling the mysteries of LUCA is a subject of intense scientific interest as it provides insights into the early evolution of life and the commonalities shared by all living organisms.
