comprehension Questions & Answers based on the provided text:
Here are some comprehension questions, ranging in difficulty, with answers based solely on the provided text.
1. What is the central idea of this study?
Answer: The central idea is that there’s a trade-off between reproduction adn lifespan in mammals. Limiting reproduction, through contraception or sterilization, is linked to an increased lifespan, suggesting that the energy and resources saved from reproduction can be redirected towards maintaining the body and increasing longevity.
2. How did the researchers gather data for this study?
Answer: The researchers analyzed records from 117 mammal species living in zoos and aquariums worldwide. They also combined this data with a meta-analysis of 71 previously published studies.
3. What was the average lifespan increase observed in mammals with limited reproduction?
Answer: The study found an average lifespan increase of about ten percent in mammals with long-term hormonal contraception or permanent surgical sterilization.
4. Why are zoos considered a “unique setting” for this type of research?
Answer: Zoos provide a unique setting because reproduction is carefully managed, allowing for natural comparison groups of animals who have received contraception or sterilization versus those who haven’t, all within the same environment.
5. What did the study reveal about how males and females benefit from reduced reproduction?
Answer: The study found that the biological pathways differed. For males, only castration (not vasectomy) increased lifespan, indicating the effect stems from eliminating testosterone. For females, several forms of sterilization were beneficial, likely due to avoiding the physical demands of pregnancy and reproductive cycling.
6. What is the “survival-health paradox” mentioned in the text, and how might this study help explain it?
Answer: The “survival-health paradox” refers to the observation that post-menopausal women often live longer than men but experience higher levels of frailty and chronic illness. The study suggests this might be as while limiting reproduction extends lifespan,it can also have downsides for later-life health outcomes,possibly weakening immune defenses.
7.What evidence exists regarding the impact of reduced reproduction on human lifespan?
Answer: Some past records of Korean Eunuchs suggest they lived about 18 percent longer than non-castrated men, but researchers caution these records are debated. Surgical sterilization in women (hysterectomy or oophorectomy) is linked to a very small (1%) reduction in lifespan.
8. According to the text, why might the effects of reproduction be different for humans compared to other mammals?
Answer: The text states that human environments – through healthcare, nutrition, and social support – can buffer or reshape the costs of reproduction.
9. How did castration effect the cause of death in male mammals?
Answer: Castrated males were less likely to die from causes linked to aggression or risky behavior.
10. In your own words, explain the “reproduction – survival trade-off.”
Answer: (This requires synthesis, but should be based on the text) The reproduction-survival trade-off means that animals have a limited amount of energy and resources. Investing heavily in reproduction – things like pregnancy, raising young, and producing sex hormones – takes away from the energy available for maintaining the body, fighting off disease, and ultimately, living a longer life. Therefore, there’s a balance between how much energy an animal puts into reproduction versus how much it puts into its own survival.