Lesson 3: Bacteria – Ecology and Diversity

🌍 Introduction: What Is Bacterial Ecology and Diversity?

Let’s start by understanding the terms:

• Ecology means how living things interact with each other and with their environment.
• Diversity means variety or differences among living organisms.

So when we say “Ecology and Diversity of Bacteria,” we mean:
➡ Where bacteria live, how they survive in different environments, and how many different types (species) of bacteria exist.

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🦠 Ancient Origins of Bacteria

Bacteria are among the oldest living things on Earth. The fossil record — which is the history of life written in rocks — shows that:

• Bacteria and another group called archaea (together known as prokaryotes) have been around for about 3.5 billion years!
• For the first 2 billion years, these tiny organisms were the only life forms on Earth.

👉 Even today, they are everywhere:

• In soil, water, air, food, and even inside the bodies of humans, animals, and plants.
• They outnumber all other life forms (like animals, plants, and fungi — the eukaryotes).

What’s even more amazing?
Some bacteria can survive in extreme environments where other organisms can’t — such as boiling hot springs, salty lakes, deep ocean vents, and even radioactive waste!