Answer:
The evolutionary mechanism that could be influencing the allele frequencies between both islands and the mainland population might be Founder Effect.
Explanation:
Genetic drift is the random change that occurs in the allelic frequency of a population through generations. The magnitude of this change is inversely related to the size of the original population. These changes produced by genetic drift accumulate in time and eventually, some alleles get lost, while some others might set. Genetic drift affects a population and reduces its size dramatically due to a disaster -bottleneck effect- or because of a population split -founder effect-. In <u>founder effect</u>, a new population originates when a few individuals who are coming from a bigger population carrying its genes, settle down in a new area and reproduce. This small population might or might not be genetically representative of the original one. Some rare alleles might be exceeded or might be completely lost. Consequently, when the small population increases in size, it will have a genetically different composition from the original one. In these situations, <u>genetic variability is reduced</u> and there exists the possibility of developing a peculiar allelic composition. If the number of individuals that originated the new population is low, the founder effect will be very extreme, because the effects of the genetic drift are inversely proportional to the original number of individuals.
<em>In the exposed situation, the evolutionary mechanism that could be influencing the allele frequencies between both islands and the mainland population might be Founder Effect. The fact that both islands are similar in their frequencies might be due to little genetic variation on island 1, or because dispersion to island 2 is a recent event on time. </em>
Answer: Option C) "excludes agricultural runoff"
Explanation:
The Clean Water Act (CWA) established in 1972 is a federal law made in United States to address the adverse effect of water pollution. The act was aimed to maintain the physical, chemical, and biological integrity of the nation's waters.
A major shortcoming of the Clean Water Act (CWA) is agricultural runoff which is a nonpoint source (NPS) pollution. Large scale agriculture activities have an adverse impact on groundwater and surfacewater as they carry heavy fertilizer, pesticide and water inputs.
The federal CWA establish water quality standards and total maximum daily loads (TMDLs) to asses the pollution caused by agricultural water with the help of regulatory mechanisms.
Hence, the correct option C.
The anthers are in the elevated position so that the pollinators will be attracted towards it, and that the pollen grains are easily carried away by the agents of pollination. The proper pollination is essential for the process of fertilization.
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A twitch is defined as a single, brief contraction period and then relaxation period of a skeletal muscle in response to a single stimulation. Contraction period involves receptive power strokes that pull the thin filaments past the thick filaments shortening sacromeres and muscle tension increases as the sacromeres shorten. Relaxation period begins with or release of cross bridges resulting from the return of Ca2+ back to sarcoplasmic reticulum. The strength of skeletal muscle contractions can be broadly separated into twitch, summation, and tetanus. A twitch is a single contraction and relaxation cycle produced by an action potential within the muscle fiber itself.
