Q: I read this background article the other day: Declines in population size can result in a loss of genetic diversity, and owing to genetic variation's role in the evolutionary potential of a species, this could in turn result in an observable Allee effect. As a species' population becomes smaller, its gene pool will be reduced in size as well. One possible outcome from this genetic bottleneck is a reduction in fitness of the species through the process of genetic drift, as well as inbreeding depression. This overall fitness decrease of a species is caused by an accumulation of deleterious mutations throughout the population. Genetic variation within a species could range from beneficial to detrimental. Nevertheless, in a smaller sized gene pool, there is a higher chance of a stochastic event in which deleterious alleles become fixed (genetic drift). While evolutionary theory states that expressed deleterious alleles should be purged through natural selection, purging would be most efficient only at eliminating alleles that are highly detrimental or harmful. Mildly deleterious alleles such as those that act later in life would be less likely to be removed by natural selection, and conversely, newly acquired beneficial mutations are more likely to be lost by random chance in smaller genetic pools than larger ones.Although the long-term population persistence of several species with low genetic variation has recently prompted debate on the generality of inbreeding depression, there are various empirical evidences for genetic Allee effects. One such case was observed in the endangered Florida panther (Puma concolor coryi). The Florida panther experienced a genetic bottleneck in the early 1990s where the population was reduced to 25 adult individuals. This reduction in genetic diversity was correlated with defects that include lower sperm quality, abnormal testosterone levels, cowlicks, and kinked tails. In response, a genetic rescue plan was put in motion and several female pumas from Texas were introduced into the Florida population. This action quickly led... I am facing a new situation today: Molly and Brian are two friends who moved away from one another after becoming close in college. They still talk on the phone regularly and see each other a couple times a year. During a recent conversation, the subject of population comes up. Molly's town is currently increasing a steady decrease in population, and Brian's town has been seeing an increase in population. Using the knowledge I acquired from the background article, how should I answer correctly the following question regarding my new situation: Which town's citizens will be on average worse at running a race?
A: Molly's
Question: I read this background article the other day: Electronegativities generally increase from left to right across a period. This is due to an increase in nuclear charge. Alkali metals have the lowest electronegativities, while halogens have the highest. Because most noble gases do not form compounds, they do not have electronegativities. Note that there is little variation among the transition metals. Electronegativities generally decrease from top to bottom within a group due to the larger atomic size. I am facing a new situation today: John was studying the periodic table. To make things easier for him he divided the table in different sections, section A, section B, section C, and section D. Section A elements are located at the left of the table, but section B elements are located at the right side of the table. Section C elements are located at the top, but section D elements are located at the bottom. Using the knowledge I acquired from the background article, how should I answer correctly the following question regarding my new situation: Which elements would have more electronegativities, section C or section D?
Answer: section C
[Q]: I read this background article the other day: Wind dispersal of seeds, or anemochory, is one of the more primitive means of dispersal. Wind dispersal can take on one of two primary forms: seeds can float on the breeze or alternatively, they can flutter to the ground. The classic examples of these dispersal mechanisms include dandelions (Taraxacum spp., Asteraceae), which have a feathery pappus attached to their seeds and can be dispersed long distances, and maples (Acer (genus) spp., Sapindaceae), which have winged seeds and flutter to the ground. An important constraint on wind dispersal is the need for abundant seed production to maximize the likelihood of a seed landing in a site suitable for germination. There are also strong evolutionary constraints on this dispersal mechanism. For instance, species in the Asteraceae on islands tended to have reduced dispersal capabilities (i.e., larger seed mass and smaller pappus) relative to the same species on the mainland. Reliance upon wind dispersal is common among many weedy or ruderal species. Unusual mechanisms of wind dispersal include tumbleweeds. A related process to anemochory is anemophily, which is the process where pollen is distributed by wind. Large families of plants are pollinated in this manner, which is favored when individuals of the dominant plant species are spaced closely together.Wind also limits tree growth. On coasts and isolated mountains, the tree line is often much lower than in corresponding altitudes inland and in larger, more complex mountain systems, because strong winds reduce tree growth. High winds scour away thin soils through erosion, as well as damage limbs and twigs. When high winds knock down or uproot trees, the process is known as windthrow. This is most likely on windward slopes of mountains, with severe cases generally occurring to tree stands that are 75 years or older. Plant varieties near the coast, such as the Sitka spruce and sea grape, are pruned back by wind and salt spray near the coastline.Wind can also cause plants damage through sand abrasion. Strong winds... I am facing a new situation today: John was studying plant varieties in different regions. He fist visited the Pacific Northwest. He found that the wind was constantly very strong there. He marked it as case A. Then he studied the plants in the Midwest. He found that on average the wind speed was very light there. He marked it as case B. Using the knowledge I acquired from the background article, how should I answer correctly the following question regarding my new situation: In which case seedlings would spend less energy to repair the damaged stems, case A or case B?
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[A]: case B
Question: I read this background article the other day: Rain dissolves fertilizer in the soil. Runoff carries it away. The fertilizer ends up in bodies of water, from ponds to oceans. Nitrogen is a fertilizer in the water. Since there is a lot of nitrogen, it causes algae to grow out of control. Pictured below is a pond covered with algae ( Figure below ). Algae use up carbon dioxide in the water. After the algae die, decomposers break down the dead tissue. The decomposers use up all the oxygen in the water. This creates a dead zone. A dead zone is an area in a body of water where nothing grows because there is too little oxygen. There is a large dead zone in the Gulf of Mexico ( Figure below ). The U.S. states outlined on the map have rivers that drain into the Gulf of Mexico. The rivers drain vast agricultural lands. The water carries fertilizer from these areas into the Gulf. I am facing a new situation today: Iceland and Ireland both used agriculture as a the main component of their economies. Ireland used lots of fertilizer and had big environmental problems as a result. Iceland does a lot of greenhouse agriculture using geothermal energy, so it is more protective towards the environment. Using the knowledge I acquired from the background article, how should I answer correctly the following question regarding my new situation: Which country had less fertilizer in their bodies of water?
Answer:
Iceland