By the early 1800s, scholars were well aware of the fact that Earth and the crea

Question

By the early 1800s, scholars were well aware of the fact that Earth and the creatures on it had changed over time, but they were at a loss to explain how or why. One early attempt to explain how organisms change over time was an idea by a scholar named Jean-Baptiste Lamarck (1744- 1829). Lamarck observed that organisms not only had adapted to their environment but also had passed on those adaptations to their young. He theorized that environmental forces encourage gradual, physical changes in an organism, and these changes are passed on to its young. Over time, these small changes build up generation to generation, creating change in a population. In other words, Lamarck proposed that evolution occurs through the following basic steps: Science Source 1. Organisms are born with certain traits. 2. Over the course of an organism's life, these traits gradually change due to pressures in the environment. The changes that occurred during an organism's life are passed on to its young. 3. This idea is similar to current understandings of how evolution works, but it is not quite correct. Which of the following situations is a counterexample that disproves Lamarck's proposed pattern of how evolution occurs? O The seeds of miniature bonsai trees germinate to become full-sized trees, not miniature bonsai trees. O If you take a red flower and plant it in a field of yellow flowers, it will not spontaneously change its color to yellow. O Horses have long legs because the act of running stretches out the legs, encouraging bone and muscle mass to stretch downward. Today, there are many common misconceptions affecting popular understanding of evolutionary theory. The following table lists just a few commonly held conceptions about evolution and natural selection. For each statement, select whether it is true or false. True or False? Natural selection is the only process that leads to biological evolution. The last common ancestor of the four-legged vertebrates had Hoxc6 genes. Biological evolution does not occur within a single generation of a population. Natural selection occurs as a result of individual organisms trying to adapt to their environment. True False

Explanation / Answer

Please find the answers below:

Answer 1: Choice 1 (according to the phenomenon of Lamarckism, the constant application of a physical stimulus tends to make the population to bear the same phenotype. However, bonsai trees are individually made to develop a specific phenotype. But the presence of normal genes in their seeds prevent observation of bonsai trees in the next generation)

Answer 2:

Part 1: False (other forces of biological evolution are mutation, gene drift, selective reproduction etc)

Part 2: True (this gene corresponds to a conserved homebox sequence found in the humans as well)

Part 3: True (evolution is a slow and gradual process arising due to accumulation of various mutations across many generations)

Part 4: True (natural selection is a process in which an individual tries to acclimatize according to its environment and hence it is selected over the other individuals who have not acclimatized)

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