Unveiling Evolution: Lamarck, Darwin, and Evidence
Lamarck’s Hypothesis on Evolution
Lamarck’s hypothesis includes ideas such as the following:
- The transformer: a worm, for example, could enter a cocoon and emerge transformed into a butterfly.
- Inheritance of acquired characters: an animal in a polluted environment will adapt to that environment.
Evidence of Evolution
In 1859, Charles Darwin’s theory on the origin of species laid the foundations of biological evolution. Darwin argued that living things that inhabit our planet are products of a process of descent with successive changes, originating from a common ancestor. Therefore, all life started from a common ancestor and evolved gradually. The mechanism by which these changes take place is natural selection.
Many natural phenomena can only be explained by the theory of evolution. Darwin provided many facts that supported his theory, which were later reinforced with new evidence, constituting what is known as the evidence of evolution. This evidence includes paleontological, comparative anatomy, comparative biochemistry, embryology, adaptation/mimicry, geographic distribution, and domestication.
Paleontological Evidence
Paleontology establishes the existence of a change process through the presence of fossil remains of extinct fauna and flora and their distribution across strata.
Comparative Anatomy Evidence
Different species have body parts formed under the same structural pattern, supporting homology between organs or similar relationships, and therefore a common origin and development over time.
Comparative Biochemistry Evidence
Homologies found to be biochemical are a highlight of the evolutionary scale.
Embryological Evidence
All species share similar ancestral characteristics in embryonic development, which disappear during the process.
Adaptation and Mimicry Evidence
In 1848, a black butterfly was discovered in Manchester, having mutated to black after adapting to the blackening of birch logs produced by factory fumes. These butterflies (originally white) perched on trunks with wings outstretched, making them easily detected by birds. Geneticist H.B.D. Kettlewell verified this fact in 1955 after releasing butterflies marked with light and dark colors, recovering twice as many from dark backgrounds as from light ones. The birds served as agents of natural selection.
Mimicry is a mechanism similar to adaptation, where animals use this feature to avoid detection, either through the adoption of certain forms or momentary changes of skin color in harmony with the environment.
Geographic Distribution Evidence
The fact that there is no uniform presence of species across the planet proves that geographic barriers or locomotion or dispersal mechanisms have prevented their distribution, even when there are suitable habitats for development.
Domestication Evidence
Domestication provides a clear example of evolutionary change caused by human intervention. Agricultural or farming activities have provided a field of experimentation on animals and plants, resulting in great variability compared to ancient specimens.