Connell's famous barnacle experiment was initiated to learn more about competitive exclusion and distribution of branacle species. Barnacle species are distributed in distinct zones on the rocky shores of the Atlantic coast. The Chthamalus in upper intertidal zone; is a smaller species and the semibalanus in low intertidal zone which is a larger species. Chthamalus found in the higher physical stress and higher temperatures because the low tide levels causes them to be exposed to the extreme outside environment for longer periods of time than the semibalanus. Additionally barnacles can only feed while submerged and the higher up shore a barnacle is, the less it can feed and grow. The experiment wanted to understand why they lived this way.
<u>Answer</u>: A heritable trait can be changed from one generation to another.
<u>Explanation</u>:
- The concept of <em>descent with modification</em> was given by Darwin which simply states that the traits are passed on from the parents to the offsprings.
- The traits that can be passed on are known as <em>heritable traits</em>.
- These traits are passed on with the help of the genes.
- So this passing on of traits explains the term <em>descent</em> in this concept. However, there are always chances that these heritable traits can be changed due to environmental factors or due to the process of recombination and thus the term <em>modification</em>.
- So <em>descent with modification</em> means that a<em> heritable trait is passed from parents to offspring but it can be changed from one generation to another.</em>
The protons have to stay the same