In 1996 a severe 6day winter storm killed more than 50 of a

In 1996 a severe 6-day winter storm killed more than 50% of a cliff swallow population in southwestern Nebraska. Biologists compared the body size of dead birds to that of surviving birds by measuring several body parts (wing length, tarsus length beak depth, etc.) and calculating a combined measure of body size. They also measured these traits in the next published in this article; Brown, C. R. and M. B. Brown 1998. Intense Natural Selection on Body Size and Wing and Tail Asymmetry in Cliff Swallows During Severe Weather. Evolution. Vol 52, No. 5pp, 1461-1475 Two other biologists. F. W. Allendorf and G. Luikart wrote a book in 2006 called Conservation and the Genetics of Populations. On page 191 Allendorf and Luikart include the 2 graphs shown at the side and state that they adapted the graphs from Brown and Brown (1998). In their caption Allendorf and Luikart state that the arrows indicate the population means. So in graph (a) one arrow, labeled \"Survived\", indicates the mean body size of birds that survived the storm. In graph (b), does \"original\" mean the entire population before the storm or only the survivors? Look at the arrow labeled \"original\". Does it appear to be in the correct place?. Explain your answer. What does your finding in part (a) suggest about the reliability of secondary sources? Apply the theory of natural selection to explain any changes in the cliff swallow populations. Your answer should include the concepts of variation, inheritance, and differential fitness. Please review the Evolution Basics PPT before you write your answer. Male long-tailed widowbirds have very long tails during the breeding season; several tail feathers are more than 16\' long on a 6\' body\' in contrast, females are plain brown with short tails. Males fly over fields of grass displaying to females. Observations show that some males attract several females while other males get no mates To test the hypothesis that females preferentially choose to mate with males

Solution

c)According to Brown and Brown observation birds which were skelletaly larger,having shorter wings and tails with less assymetry in wings survived. Nature the birds with more assymetrical wing span and smaller skeletal structire to die out. Changes in bill size and wing lenghth helped the surviving species to build nest and prey insects more efficiently.Thus they could survive the 6-day winter storm. This the explanation according to natural selection.

a) In graph b ,original means the population that survived after the stom whose characteristics is plotted with the next generation.The arrow is not in the correct place as it should be on the black bars as it refers to the surviving population.