In most animals, the genotype of the organisms determines their sex. What is the relationship between sex determination and the environment?
What will be an ideal response?
Answer: Temperature-dependent sex determination (TSD) is one form of environmental sex determination that is common in reptiles: all crocodilians and sea turtles, and in some species of lizards and terrestrial turtles. At the pivotal temperature (intermediate ambient temperature), equal numbers of male and female offspring are produced. Three patterns have been observed from studies of TSD: 1) In some species of turtles, female offspring are produced above the pivotal temperature while males are produced below; 2) some species of lizards produce males when the temperatures are high and females when temperatures are low; and 3) in crocodiles and alligators, larger numbers of female offspring are produced at both low and high temperatures, while the abundance of male offspring is higher at intermediate temperatures.
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The two types of information needed to predict the inheritance pattern of a trait are
A. the way mitosis distributes the alleles of a gene and whether those alleles are dominant or recessive. B. the health of the mother and the father. C. the way genes are distributed in meiosis and the way that they come together when sperm joins egg. D. the age at which the trait appears and how it affects males or females.
Testosterone is:
a. produced by the prostate gland b. produced by the interstitial cells of the testes c. the masculinizing hormone d. both B and C above
Interferon, natural killer cells, and cytotoxic T cells all exert antiviral and anticancer effects
Indicate whether the statement is true or false
In both the anterolateral pathway and the posterior funiculus-medial lemniscal pathway, the axons of the ________ neurons decussate in the CNS
A. primary B. secondary C. tertiary D. quaternary