Final answer:
Bacteria are the most commonplace, abundant, and diverse form of life on Earth. They inhabit nearly all environments and have a population estimated to be 5 x 1030. Bacteria's success stems from their adaptability and essential roles in various ecological systems.
Step-by-step explanation:
Bacteria are the most common, diverse, and abundant forms of life on Earth. This remarkable abundance is attributed to their ability to adapt and survive in various environmental conditions. Bacteria are found practically on every surface and thrive in environments ranging from the deepest oceans to soil and even inside the bodies of other organisms. It’s estimated that there are 5 x 1030 bacteria on Earth, a figure which highlights their immense population.
Due to their simplistic structure as prokaryotic organisms, bacteria can live in extreme conditions that would be inhospitable to more complex life forms. This adaptability has allowed them to flourish for billions of years, evolving into a multitude of species with a variety of functions, including some that survive in harsh conditions similar to those of the early Earth. The first life forms are thought to be even simpler than modern bacteria, yet, today’s bacteria are a testament to the evolutionary success of these microorganisms.
Their success is also measured by their essential role in ecological systems and in the health of larger organisms, including humans. Bacteria play critical roles in processes such as digestion and nutrient cycling, making life as we know it possible. Their presence in and on our bodies in numbers greater than our own cells highlights their significance in our own biology.