Dogs are widely used by the police as biological recognition systems to detect drug smuggling and drug caches. Yet recent eviden
ce suggests that insects, rather than mammals, might be used more effectively in this capacity. In the 1950s, German biologist Dietrich Schneider developed the first method that enabled researchers to record activity in insect olfactory nerves and to identify the compounds or class of compounds that trigger a particular behavioral response. The position of the insect olfactory organs on the surface of its body allows for direct investigation of the system’s response. Schneider’s technique formed the foundation of an olfactory detection system based upon insects, a system that is at least as effective as the ones based upon mammals.Insects have olfactory systems that are very similar to those of vertebrates. Insects first detect odors via finger-like protuberances on the antenna, called olfactory sensilla. The odorant molecules pass through pores in the outer cuticle of the sensilla and become attached to an odorant-binding protein. This protein carries the hydrophobic molecules through the lymph fluid found inside the cell and attaches them to receptors on the dendritic projections of a sensory nerve cell. Finally, these receptors send signals to the central nervous system, allowing researchers to detect and interpret the responses.It can be inferred from the passage that insects would be less useful for helping researchers to detect drugs if which of the following were true?A) They were as accurate as, but not more accurate than, dogs in detecting drugs.B) Insect olfactory systems did not deliver odorants to nerve cells, as vertebrate olfactory systems do.C) Dietrich Schneider did not develop the first method that enabled researchers to record the activity in insect olfactory nerves.D) They did not have finger-like protuberances for detecting odors.E) The signal sent to the insect’s central nervous system did not allow researchers to classify the compound that triggered the response.
Answer - A The ratio of a child with clear skin with that of freckled skin is 1:2. When genotype rr mates with genotype Rr, the following genotypes are expected: Rr = clear skin dominant rr= freckled skin
