Understanding Lamarck’s Theory of Evolution and Giraffes
Understanding Lamarck’s Theory of Evolution
Lamarck’s theory published in Philosophie Zoologique can be summarized in these points:
Key Points of Lamarck’s Theory
- All living things are products of nature and have evolved over a long time.
- Spontaneous generation is a fact; organisms can arise anywhere.
- Living matter has inherent properties that allow it to progress alongside environmental changes.
- The use of an organ that is commonly and frequently used develops slowly in proportion to its use. Similarly, the lack of use weakens the organ and may lead to its disappearance.
- All that has been acquired or lost under the influence of the environment is conserved in the offspring: Law of acquired characteristics.
Example: The Giraffe’s Long Neck
The paradigmatic example of Lamarckian evolution is the explanation of the long neck of giraffes. At that time, this phenomenon had recently been discovered. Giraffes have long necks because:
- Giraffes eat the leaves of acacia trees, which are becoming increasingly scarce at lower heights.
- Each generation strives to reach higher trees to eat.
- The increased neck length is transmitted to successive generations.
- After many generations, giraffes have developed long necks.
In summary, the Law of acquired characteristics is the essence of Lamarck’s theory of evolution.