Evolutionary Theories and Evidence: From Redi to Lamarck

Redi’s Experiment

Redi placed pieces of the same type of meat in three jars. He left open the first jar, covered the second with fabric, and closed the third with cork. After a few days, maggots were found in the first two jars, but not the third.

Pasteur’s Experiment

Pasteur placed meat soup in two flasks with an S-shaped neck. After sterilizing the liquid, he observed decomposition in one flask. Cutting the neck of the other flask led to decomposition. Conclusion: S-shaped neck prevented microorganisms from entering.

Oparin’s Theory

Step 1: Abiotic synthesis of monomers from simple organic compounds. Step 2: Monomers combined to form polymers. Step 3: Formation of coacervates. Step 4: Origin of nucleic acid and protein controlled metabolism inside a lipid membrane.


Species always stay the same, according to Cuvier’s Catastrophism. Creationism states living things were created as they are today.


Charles Lyell popularized the idea that the Earth was shaped by the same processes still in operation today.

The Present Day Hypothesis

Possible places where living things could have first appeared, such as deep-sea hydrothermal vents.


Changes that lead to the appearance of new species and large groups of organisms after drastic change. Biodiversity refers to the wide variety of living things on our planet.

Theory of Spontaneous Generation

Humans once thought life began from inanimate objects. Jan Baptist Van Helmont’s experiment and Panspermia theory.

Anatomical Evidence

Comparing the anatomy of living things with fossils. Homologous, analogous, and vestigial organs.

Fossil Evidence

Organisms that existed in the past and are different from present-day organisms. Fossils support evolutionary theories and are considered evolutionary links.

Embryological Evidence

Embryological development as a summary of evolution. Coevolution, mutualism, parasitism, mimesis, and domestication.

Molecular Evidence

Study of molecules found in living things reveals evolutionary relationships.

Biogeographical Evidence

How species are distributed on the planet.

Origin of Species (SPECIATION)

Genetic isolation, gradual differentiation, speciation, and punctuated equilibrium.


Jean-Baptiste Lamarck’s theory of inheritance of acquired traits.