Chemical and Biological Evolution: From Molecules to Biodiversity

Posted on Mar 2, 2025 in Geology

Chemical Evolution

Refers to the processes that created the molecules that make up living things (biomolecules), and then formed structures called protocells, which exhibited a certain organization and were separated from the environment by membranes:

  • Biomolecules were created.
  • More and more complex biomolecules were created.
  • Protocells were formed.

Biological Evolution

Processes that led protocells to become different types of cells, and resulted in all the different organisms ever to have inhabited the Earth:

  • Primitive cells were formed.
  • Different types of prokaryotic cells were created.
  • The first eukaryotic cells appeared as a result of endosymbiosis.

Theories About the Origin of Biodiversity

Fixist Theories

Uphold the idea that the species that currently exist on Earth were created by God and they have not changed in any way. Cuvier proposed the theory of catastrophism. According to this theory, Earth had experienced several events and because of that, a lot of species had disappeared.

Evolutionary Theories

Actualism: Events of Earth’s distant past were caused by the action of forces that are identical to those that are in operation today.

Evolutionism: Maintains that species undergo a process of transformation which results in the appearance of new species.

Lamarck’s Theory

  • Spontaneous generation (appearance of the simplest life forms, which had evolved into more complex organisms).
  • An internal impulse exists within organisms that drives them to improve themselves and become more complex.
  • The characteristics acquired through their use or disuse are transferred to the next generation: they are inheritable traits.

Darwin’s Theory

  • The world is not static, but in a process of transformation.
  • The process of change is gradual and continuous.
  • Similar organisms are related and have a common ancestor.
  • Evolutionary change is the result of natural selection.

Natural Selection

Is a process that favors the individuals in populations that are best adapted to the environment and which, over time, will lead to the appearance of new species.

Neo-Darwinism

Also known as the synthetic theory, it is a revised version of the theory of natural selection, enriched by contributions from studies made in fields such as genetics, paleontology, and taxonomy after Darwin’s time.

Proof of Evolution

Evidences

  • Comparative Anatomy:
    • Homologous organs: Same origin and same basic structure, although their shape is different as a result of adaptation to different functions.
    • Analogous organs: These are the organs that have a different origin but a similar shape, as they have adapted to the environment to perform the same function.
  • Paleontological: It is the science that studies the history of the Earth through its fossils. Fossils are the remains of ancient living things.
  • Biogeographical Evidence: Study of the distribution of living things over different areas of the Earth also provides evidence of evolution.
  • Embryological Evidence
  • Molecular Evidence: There exists a fact that says that all living things are made up of the same type of molecules; this fact tells us that we all have a common origin.