Describe the interactions between genes and the environment in the sex determination of some reptiles; explain their relevance to human sex determination
What will be an ideal response?
Maleness and femaleness are determined by complex interactions between genes and the environment. Sex determination in some reptiles illustrates the role of environmental factors in determining sex. The internal temperature of the nest in which the eggs develop determines the sex of the offspring. In some species, higher temperatures produce females and lower temperatures produce males. In other species, the opposite is true. From the study of humans, it is clear that someone having an XX or XY chromosome set does not always mean someone develops as a female or male. The outcome depends on the distribution and expression of genes on the X and Y chromosomes and interactions between genes on these chromosomes with many different environmental factors.
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A phage
a. can be found in all living organisms. b. is specific to a particular organism. c. is found in mammals. d. is specific for bacteria. e. is specific for vertebrates.
Mendel would not have seen four different
phenotypes in the F2 generation of his dihybrid crosses if a. the genes were on the same chromosomes. b. the P1 generation was homozygous. c. purple was dominant to white. d. more than two traits were traced. e. all of these are true.
In the above figure, which of the following would
have a haploid number of chromosomes? a. zygote b. multicelled sporophyte c. spores d. multicelled gametophytes e. both c and d
An innate ability to move in a particular direction is called
A. map sense. B. direction sense. C. compass sense. D. timely sense.