1st life on earth was

Options

A. Cyanobacteria
B. Chemoheterotrophs
C. Autotrophs
D. Photoautotrophs

Answer

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks about the first life forms on Earth. We need to identify which type of organism was the earliest to appear.

2. **Options Analysis**: The options provided are:
- A) Cyanobacteria
- B) Chemo-hydrotropes
- C) Autotropes
- D) Photo-autotropes

3. **Identifying the Correct Answer**: According to the video transcript, the correct answer is **B) Chemo-hydrotropes**.

4. **Explanation of Chemo-hydrotropes**:
- Chemo-hydrotropes are the first living organisms that formed in the ocean.
- They thrived in an environment rich in organic molecules.
- Their method of obtaining nutrition involved the absorption of organic material, which is characteristic of chemo-hydrotropic nutrition.

5. **Characteristics of Early Life**:
- These organisms were prokaryotic.
- They obtained energy through the fermentation of organic matter.
- The environment in which they existed was an oxygen-free (O2-free) atmosphere, also referred to as a reducing atmosphere.

6. **Subsequent Developments**: After the emergence of chemo-hydrotropes, autotrophs appeared, leading to a rapid increase in heterotrophs, which eventually impacted the availability of nutritional sources in the sea.

7. **Conclusion**: Thus, the first life forms on Earth were chemo-hydrotropes, which played a crucial role in the early development of life in a reducing atmosphere.

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