Jean-Baptiste de Lamarck proposed a mechanism for how life changes over time. Explain the
two principles of his mechanism. use and disuse inheritance of acquired characteristics
Although Lamarck\'s mechanism of evolution does not explain the changes in species over time,
his thinking has been influential. What is considered to be the great importance of his ideas?
Concept 22.2 Descent with modification by natural selection explains the adaptations of
organisms and the unity and diversity of life Charles Darwin proposed that the mechanism of
evolution is natural selection and that it explains how adaptations arise. What are adaptations?
Give two examples of adaptations.
Solution
Lamarck theorized early concepts of evolution. One of his principles \'use and disuse\' mentioned
that individuals lose the characteristics over time if they are not used and they gain
characteristics if they are used. If the organism started using a body part/organ more, then it
would develop more in the life time. He explained this with the example of giraffes where they
had to use their necks more to reach and eat the high placed leaves in the trees. This increased
use of their necks strengthened it and gradually increased its length. Example for the disuse of
organ - he mentioned about the appendix in humans which is not being used and is slowly
diminishing in size over time.
The second principle was Inheritance of acquired characteristics: This mentioned that the
changes in features and characteristics that were gained in the lifetime of an individual wil be
transmitted to the next generation offspring. he supported this too with the example of giraffes
mentioning that the long neck once acquired by a giraffe to reach high leaves, is transmitted to
the giraffe offspring..
Jean-Baptiste de Lamarck proposed a mechanism for how life changes ov.pdf
1. Jean-Baptiste de Lamarck proposed a mechanism for how life changes over time. Explain the
two principles of his mechanism. use and disuse inheritance of acquired characteristics
Although Lamarck's mechanism of evolution does not explain the changes in species over time,
his thinking has been influential. What is considered to be the great importance of his ideas?
Concept 22.2 Descent with modification by natural selection explains the adaptations of
organisms and the unity and diversity of life Charles Darwin proposed that the mechanism of
evolution is natural selection and that it explains how adaptations arise. What are adaptations?
Give two examples of adaptations.
Solution
Lamarck theorized early concepts of evolution. One of his principles 'use and disuse' mentioned
that individuals lose the characteristics over time if they are not used and they gain
characteristics if they are used. If the organism started using a body part/organ more, then it
would develop more in the life time. He explained this with the example of giraffes where they
had to use their necks more to reach and eat the high placed leaves in the trees. This increased
use of their necks strengthened it and gradually increased its length. Example for the disuse of
organ - he mentioned about the appendix in humans which is not being used and is slowly
diminishing in size over time.
The second principle was Inheritance of acquired characteristics: This mentioned that the
changes in features and characteristics that were gained in the lifetime of an individual wil be
transmitted to the next generation offspring. he supported this too with the example of giraffes
mentioning that the long neck once acquired by a giraffe to reach high leaves, is transmitted to
the giraffe offspring.
