Arrange the following events of "biogeny theory" in a sequence.
A. Formation of coacervates
B. Aerobic organisms came to existence
C. Heterotrophic organisms began to form
D. Mycoplasmas are first formed cells

Key Points

• Biogeny theory explains the origin of life on Earth through gradual chemical and biological processes.
• In the correct sequence:
  1. Formation of coacervates (pre-cellular structures that marked the beginning of organization).
  2. First cells (Mycoplasmas) were formed, which were simple and lacked a rigid cell wall.
  3. Heterotrophic organisms began to form, relying on external organic molecules for energy.
  4. Aerobic organisms emerged, utilizing oxygen for respiration as oxygen levels in the atmosphere increased.
• Coacervates are aggregates of macromolecules that exhibit primitive cell-like properties, marking the early stages of life development.
• This theory aligns with the gradual steps of life evolution from simple chemicals to complex life forms.

Important Points

• Biogeny theory is rooted in concepts proposed by Oparin-Haldane and later supported by experiments such as Miller-Urey.
• Formation of coacervates was a critical step, as they could absorb and concentrate organic molecules.
• Heterotrophic organisms evolved to utilize organic matter, marking the transition to biological functions.
• Aerobic organisms appeared after oxygen levels in the atmosphere rose due to photosynthetic activity by primitive organisms.