Exam 46: Animal Reproduction

Increasing the temperature of the human scrotum by 2°C (that is, near the normal body core temperature) and holding it there would most likely ________.

Human sperm cells first arise in the ________.

An ectopic pregnancy occurs when a fertilised egg implants somewhere other than in the lining of the uterus. Usually it implants in the oviduct. Which of the following would be the most likely explanation for such a pregnancy being unsuccessful?

In male mammals, excretory and reproductive systems share

Oestrogens found in the environment have raised concerns about effects on reproductive health of animals. Researchers studied the effects that oestrogens in the water have on sexual differentiation in zebrafish. They exposed embryo-larval (0-21 days post-hatching), juvenile (21-42 days post-hatching), and adult (over 200 days post-hatching) fish to three concentrations of 17β-oestradiol (5, 25, and 100 nanograms/litre) that are within the range of concentrations found in water leaving sewage treatment plants in different countries. They then examined the proportion of males and females when the fish exposed at embryo-larval and juvenile stages reached adulthood. Embryo-larval stage fish that had been exposed to 100 ng/l 17β-oestradiol resulted in adult populations that had substantially more females than males compared to control groups. Embryo-larval fish that had been exposed to 5 and 25 ng/l of 17β-oestradiol did not show a statistically significant shift in the proportion of females. (Brion, F., C. R. Tyler, X. Palazzi, B. Laillet, J. M. Porcher, J. Garric, and P. Flammarion. 2004. Impacts of 17β-oestradiol, including environmentally relevant concentrations, on reproduction after exposure during embryo-larval-, juvenile-, and adult-life stages in zebrafish (Danio rerio). Aquatic Toxicology 68:193-217.) -What is the significance of using the concentrations of 5, 25, and 100 ng/l of 17β-oestradiol in this experiment?

Genetic mutations in asexually reproducing organisms lead to more evolutionary changes than do genetic mutations in sexually reproducing ones because ________.

Refer to the following figure, which diagrams the reproductive anatomy of the human male, to answer the question. In the figure, which letter points to the vas deferens?

For which of the following is the number the same in spermatogenesis and oogenesis?

Among non-mammalian vertebrates, the cloaca is an anatomical structure that functions as ________.

In close comparisons, external fertilisation often yields more offspring than does internal fertilisation. However, internal fertilisation typically offers the advantage that ________.

Refer to the following figure, which diagrams the reproductive anatomy of the human male, to answer the question. In the figure, which letter points to the prostate gland?

Evidence that parthenogenic whiptail lizards are derived from sexually reproducing ancestors includes ________.

Refer to the following figure, which diagrams the reproductive anatomy of the human female, to answer the question. In the figure, which letter points to the corpus luteum?

Which statement about human reproduction is correct?

For your internship at the local zoo, you have been assigned to help with the new orangutan-breeding program. Little is known about orangutan reproductive hormones, but hormone feedback cycles are often the same in closely related animals. You have been asked to use your knowledge of the interactions of human reproductive hormones to recommend injections to promote ovulation in a female orangutan when a visiting male arrives for a brief breeding visit. -Which of the following hormones would you use if you want to induce ovulation right away?

Refer to the following figure, which diagrams the reproductive anatomy of the human female, to answer the question. In the figure, which letter points to the cervix?

For water fleas of the genus Daphnia, switching from a pattern of asexual reproduction to sexual reproduction coincides with ________.

A physician finds that a nine-year-old male patient is entering puberty much earlier than usual. Such a condition is most likely the result of a tumour in the ________.

The primary difference between oestrous and menstrual cycles is that ________.

On a submarine expedition to the ocean bottom, you discover a population of fish that are only female. What type of reproduction does this fish most likely use?