97. A hormone facilitates oogenesis in mammals. The same hormone down regulates the transfer of nutrients from the placenta. The likely effect of the hormone on life history strategies is that it facilitates
    (1) ‘r’ type of reproduction.
    (2) ‘K’ type of reproduction.

Introduction

Hormones play a pivotal role in shaping the reproductive strategies of mammals. Some hormones not only facilitate the development of eggs (oogenesis) but also influence how nutrients are transferred from the placenta to the developing fetus. When a hormone promotes oogenesis while simultaneously downregulating placental nutrient transfer, it has significant implications for the evolutionary life history strategies of the species.

Hormonal Effects on Reproduction and Placenta

Certain placental hormones, such as placental lactogens and chorionic gonadotropins, have evolved to regulate a variety of reproductive functions, including oogenesis and nutrient transfer. The placenta is central to fetal development, acting as a conduit for nutrients, gases, and hormones between mother and fetus. When nutrient transfer is limited by hormonal action, the developing offspring may receive less maternal investment per pregnancy.

Life History Strategies: r-Type vs. K-Type

Life history strategies in mammals are often categorized as r-type or K-type:

• r-type reproduction is characterized by high reproductive rates, early maturity, production of many offspring, and low parental investment per offspring.

• K-type reproduction involves fewer offspring, later maturity, and high parental investment, often resulting in higher offspring survival.

Hormonal Influence on Life History Strategy

A hormone that facilitates oogenesis (increasing the number of eggs or potential offspring) but downregulates placental nutrient transfer (reducing investment per offspring) will push the reproductive strategy toward:

• More offspring per reproductive event

• Lower investment in each individual offspring

• Potentially lower survival rates per offspring

This pattern aligns with r-type reproduction, where the emphasis is on quantity rather than quality of offspring.

Conclusion

A hormone that promotes oogenesis while downregulating placental nutrient transfer will facilitate r-type reproduction. This strategy favors producing many offspring with less investment in each, increasing the likelihood that at least some will survive in unpredictable environments.

Correct answer:
(1) ‘r’ type of reproduction.