Which of the following best describes Jean-Baptiste Lamarck's ideas about evolution, and why are they considered incorrect today?

• A. Lamarck believed that mutations in DNA are the primary source of evolutionary change; this is incorrect because he did not understand genetics.
• B. Lamarck proposed that organisms could acquire traits during their lifetime and pass them on to their offspring; this is incorrect because acquired traits do not alter genetic material and cannot be inherited.
• C. Lamarck argued that all species were created independently and do not change over time; this is incorrect because he actually believed in species change.
• D. Lamarck suggested that evolution occurs through natural selection acting on heritable variation; this is incorrect because he did not recognize the role of natural selection.

Answer: (B)

Verified step by step guidance

1. Step 1: Understand the historical context of Jean-Baptiste Lamarck's ideas. Lamarck was an early evolutionary thinker who proposed a mechanism for how species change over time, predating Darwin's theory of natural selection.
2. Step 2: Examine Lamarck's central idea, known as the theory of inheritance of acquired characteristics. He suggested that organisms could acquire traits during their lifetime through use or disuse of certain features and pass these traits to their offspring. For example, he believed that giraffes stretched their necks to reach higher leaves, and this acquired longer neck trait was inherited by their descendants.
3. Step 3: Identify why Lamarck's theory is considered incorrect today. Modern genetics has shown that acquired traits, such as muscle growth from exercise or neck stretching, do not alter the DNA in germ cells (sperm and egg). Only genetic changes in germ cells can be passed to offspring.
4. Step 4: Compare Lamarck's ideas to the modern understanding of evolution. Today, we know that evolution occurs through mechanisms like natural selection acting on heritable genetic variation, mutations, and genetic recombination, which Lamarck did not account for.
5. Step 5: Clarify misconceptions about Lamarck's beliefs. He did not argue that species were created independently or that evolution occurs through natural selection. Instead, his focus was on the inheritance of acquired traits, which is why his ideas are considered outdated in light of modern evolutionary biology.