Lamarckism: The Theory of Acquired Characteristics
Jean-Baptiste Lamarck believed that an organism's environment creates a "need" for change. He thought animals could intentionally adapt during their lifetime.
Example: A blacksmith who develops large muscles through work would have babies born with naturally large muscles.
Key points of Lamarck's theory:
- Internal Drive
- Use and Disuse
- Inherited Habits
Darwinism: Evolution by Natural Selection
Darwin's theory of evolution by natural selection explains how species change over time. Here are the main ideas in simple words:
- Variation: Individuals in a species are not all the same. They have different traits like size, color, or speed.
- Inheritance: These traits can be passed from parents to offspring.
- Overproduction: More babies are born than can possibly survive.
- Struggle for existence: Because there are too many individuals, they have to compete for food, shelter, and safety.
- Survival of the fittest: Individuals with traits that help them survive in their environment are more likely to live and reproduce.
- Natural selection: Over many generations, these helpful traits become more common in the population. This is how evolution happens.
Example: In a drought, birds with slightly stronger beaks can crack hard seeds that others can't. They survive and pass that trait on. Over time, more birds in the population have strong beaks.
Key points of Darwin's theory:
- Variation
- Inheritance
- Overproduction
- Struggle for Existence
- Survival of the Fittest
- Natural Selection
📊 Side-by-Side Comparison
| Feature | Lamarckism | Darwinism |
|---|---|---|
| Who changes? | The individual changes its own body. | The population changes over generations. |
| Role of Environment | Environment causes the change to happen. | Environment selects existing variations. |
| Role of Effort | Based on use, disuse, and 'need'. | No effort involved; based on luck/genetics. |
| Scientific Proof | Proven wrong (DNA doesn't work this way). | Proven right (supported by modern genetics). |