Concept explainers
Sperm Counts Down on the Farm Contamination of water by agricultural chemicals affects reproductive function in some animals. Are there effects on humans? Epidemiologist Shanna Swan and her colleagues studied sperm from men in four cities in the United States (FIGURE 34. 22). The men were partners of women who had become pregnant and were visiting a prenatal clinic, so all were fertile. Of the four cities, Columbia, Missouri, is located in the county with the most farmlands. New York City in New York is in an area with no agriculture.
Location of Clinic | ||||
Columbia, Missouri | Los Angeles, California | Minneapolis, Minnesota | New York, New York | |
Average age | 30.7 | 29.8 | 32.2 | 36.1 |
Percent nonsmokers | 79.5 | 70.5 | 85.8 | 81.6 |
Percent with history of STD | 11.4 | 12.9 | 13.6 | 15.8 |
Sperm count (million/ml) | 58.7 | 80.8 | 98.6 | 102.9 |
Percent motile sperm | 48.2 | 54.5 | 52.1 | 56.4 |
FIGURE 34.22 Characteristics men h four cities. All men were partners of woman who visited prenatal health clinics, and so were presumably fertile. STD stands for sexually transmitted disease.
2. In which cities did samples show the highest and lowest sperm motility (ability to move)?
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Biology: The Unity and Diversity of Life (MindTap Course List)
- Sperm Counts Down on the Farm Contamination of water by agricultural chemicals affects reproductive function in some animals. Are there effects on humans? Epidemiologist Shanna Swan and her colleagues studied sperm from men in four cities in the United States (FIGURE 34. 22). The men were partners of women who had become pregnant and were visiting a prenatal clinic, so all were fertile. Of the four cities, Columbia, Missouri, is located in the county with the most farmlands. New York City in New York is in an area with no agriculture. Location of Clinic Columbia, Missouri Los Angeles, California Minneapolis, Minnesota New York, New York Average age 30.7 29.8 32.2 36.1 Percent nonsmokers 79.5 70.5 85.8 81.6 Percent with history of STD 11.4 12.9 13.6 15.8 Sperm count (million/ml) 58.7 80.8 98.6 102.9 Percent motile sperm 48.2 54.5 52.1 56.4 FIGURE 34.22 Characteristics men h four cities. All men were partners of woman who visited prenatal health clinics, and so were presumably fertile. STD stands for sexually transmitted disease. 4. Do these data support the hypothesis that living near farmlands can adversely affect male reproductive function?arrow_forwardSperm Counts Down on the Farm Contamination of water by agricultural chemicals affects reproductive function in some animals. Are there effects on humans? Epidemiologist Shanna Swan and her colleagues studied sperm from men in four cities in the United States (FIGURE 34. 22). The men were partners of women who had become pregnant and were visiting a prenatal clinic, so all were fertile. Of the four cities, Columbia, Missouri, is located in the county with the most farmlands. New York City in New York is in an area with no agriculture. Location of Clinic Columbia, Missouri Los Angeles, California Minneapolis, Minnesota New York, New York Average age 30.7 29.8 32.2 36.1 Percent nonsmokers 79.5 70.5 85.8 81.6 Percent with history of STD 11.4 12.9 13.6 15.8 Sperm count (million/ml) 58.7 80.8 98.6 102.9 Percent motile sperm 48.2 54.5 52.1 56.4 FIGURE 34.22 Characteristics men h four cities. All men were partners of woman who visited prenatal health clinics, and so were presumably fertile. STD stands for sexually transmitted disease. Aging, smoking, and sexually transmitted diseases adversely affect sperm. Could differences in any of these variables explain the regional differences in sperm count?arrow_forwardSperm and ova are similar in terms of ________. size quantity produced per year chromosome number flagellar motilityarrow_forward
- Birth Defects and Multiple Births A woman who carries multiple offspring at the same time increases the risk of some birth defects. FIGURE 42.18 shows the results of Yiwei Tang's study of birth defects reported in Florida from 1W6 to 2000. Tang compared the incidence of various defects among single and multiple births. She calculated the relative risk for each type of defect based on type of birth, and corrected for other differences that might increase risk such as maternal age, income, race, and medical care during pregnancy. A relative risk of less than 1 means that multiple births pose less risk of that defect occurring. A relative risk greater than 1 means multiples are more likely to have a defect. FIGURE 42.18 Prevalence, per 10,000 live births, of various types of birth defects among multiple aria single births. Relative risk for each defect is given after researches adjusted for the motor's age, race, previous adverse pregnancy experience, education, Medicaid participation during pregnancy, as well as the infant's sex and number of siblings. 4. Does a multiple pregnancy increase the relative risk of chromosomal defects in offspring?arrow_forwardTRUE OF FALSE Primary spermatocytes are diploid in number like spermatogonia while spermatocytes are haploid in number. Spermatogenesis is the final stage of reproductive cell division by which there is the development of haploid spermatids into sperm. Spermiation is the event by which sperm are released from their connections to Sertoli cells. Digestive secretions from the small intestine complete the digestion of carbohydrates, proteins, and lipids. Bacteria in the large intestines produce minerals and nucleic acids.arrow_forwardFill in the blank: The _______________________ is the funnel-shaped expansion at the end of a uterine tube.arrow_forward
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- JUST ANSWER the NUMBER 5. Three pregnant women due to give birth were admitted to a hospital, accompanied by their partners on the same night. Given that the hospital staff forgot to put name tag on the babies, to be able to identify which baby goes with which couple, a blood test was performed with the following results:arrow_forwardFill in the blank: The number of chromosomes normally present in a human sperm cell is _______________________.arrow_forwardIn humans, one primary spermatocyte yields _____ sperm and _____ polar body(ies), while one primary oocyte yields _____ oocyte(s) and _____ polar body(ies). 1; 2; 1; 2 1; 2; 4; 0 4; 0; 1; 2 4; 0; 4: 0 2; 2; 2; 2arrow_forward
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