Among the following patterns, which is likely to represent the phenomenon of senescence? Please note that the x-axis represents the age and the y-axis the number of offspring (the solid lines) or the probability of survival (the dashed lines). (A) (B) (C) (D)

In a shocking discovery, biologists discover dragons! Dragon geneticists determine that flame eyes (F) are dominant to blue eyes (f) and burbling (B) is dominant to whistling (b). They suspect that the two genes are linked in one of the autosomes. They mate a true-breeding, flame-eyed, burbling female with a true-breeding, blue-eyed, whistling male. They then mate a pair of offspring.  a) Assuming dragon genetics follows the same rules as fruit flies, what ratio of phenotypes would you expect in the F2 generation if the genes were not linked? (Remember you are crossing FfBb x FfBb).   b) If the genes are linked, which of the  F2 phenotypes would occur at a lower frequency than would be expected if the genes were not linked?

In African clawed toads, albino skin (a) is recessive to green skin (A). Two toads are mated. One of the parents has green skin and one has albino skin. Among the resulting offspring are twenty albinos and eighteen greens. (Show your work below!) (a) What is the genotype of the green parent? (b) What is the genotype of the albino parent? (c) What are the genotypes of the offspring? Greens Albinos (d) Did segregation of alleles occur? (e) Did independent assortment of alleles occur? (f) Explain your answers. (g) Which of Mendel’s Laws is demonstrated by this example?

Because of non-disjunction in some stocks of Drosophila. melanogaster, about 1 in 65,000 egg cells have two copies of the X chromosome and about 1 in 375 egg cells have no X chromosome. Assuming that meiosis in males is ‘always normal', what is the expected frequency of XXX females and XO males arising from any number of fertilized eggs? Do not be concerned as to whether it is lethal or not.

Is senescence inevitable? Please explain your answer, accounting for the great variation inpatterns of aging among different species.

In fruit flies, chromosomal crossing over does not occur in meiosis in males, whereas crossing over does occur in meiosis in females. In fruit flies that are heterozygous at many genes (i.e. many maternal and paternal versions of the genes differ), at what stage would cells no longer be heterozygous for any gene during the process of meiosis? a)After the second meiotic division in males, and after the first meiotic division in females. b)After the second meiotic division in both males and females. c)After the first meiotic division in both males and females. d)After the first meiotic division in males, and after the second meiotic division in females.