Lamarckism facts for kids
Lamarckism is an old idea about how living things change over time. This change is called evolution. Today, most scientists believe in the ideas of Charles Darwin, which explain evolution through natural selection.
Lamarckism was developed by a French scientist named Jean-Baptiste de Lamarck. He thought that animals could pass on traits they gained during their lives to their children. For example, Lamarck believed that giraffes got their long necks because their ancestors stretched their necks to reach high leaves. He thought these stretched necks were then passed down to their babies. This idea is called the inheritance of acquired characteristics.
Charles Darwin's ideas were different. He focused on how individuals that are better adapted to their environment are more likely to survive and have babies. These successful individuals pass on their helpful traits.
Later, Gregor Mendel discovered the basic rules of heredity, which is how traits are passed from parents to children. Mendel's rules showed that Lamarck's ideas about acquired characteristics being inherited were wrong. This is why Lamarck's theory is no longer accepted as the way evolution happens. However, both Lamarck and Darwin agreed that evolution does happen.
Lamarck's Ideas on Evolution
Lamarck's theory was more complex than just the idea of inherited acquired traits. Some historians say that focusing only on this one part makes his ideas seem too simple. Lamarck had a full system to explain how evolution works.
He believed evolution happened through two main forces:
- A force that makes things more complex: Lamarck thought that living things naturally become more complex over time. This force would make organisms go from simple to more complicated forms.
- A force that helps things adapt: He also believed that how an animal used its body parts would change them. If an animal used a part a lot, it would grow stronger or bigger. If it didn't use a part, it would shrink. This would help animals adapt to their environment.
So, Lamarck thought that if an environment changed, an animal's needs would change. This would lead to new behaviors, which would change how body parts were used. Over time, these changes would lead to the gradual change of the species.
Today, scientists know that neither of Lamarck's "forces" truly exists in the way he described. However, Lamarck was one of the first to create a complete theory of evolution. Even though his ideas about how it happened were wrong, he helped start the discussion about evolution.
Images for kids
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The long neck of the giraffe is often used as an example in popular explanations of Lamarckism.
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Paul Kammerer
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Trofim Lysenko promoted an ideological form of neo-Lamarckism.
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DNA molecule with epigenetic marks, which can sometimes lead to a pattern of inheritance similar to Lamarckism for a few generations.
See also
In Spanish: Lamarckismo para niños
