The Two Worlds of Reproductive Physiology

What Aspects of Reproduction Do Physiologists Study?

• BOX 17.1 A New Discovery: Genetically Linked Sets of Reproductive Traits

The Environment as a Player in Reproduction

• Temperature and photoperiod are often used as cues
• Latitudinal trends graphically illustrate the importance of the environment
• Animals living in distinctive habitats often use distinctive cues for reproduction

Reproduce Once or More Than Once?

• BOX 17.2 Semelparity in a Mammal

Eggs, Provisioning, and Parental Care

External or Internal Fertilization?

The Timing of Reproductive Cycles

• Sperm storage permits flexible timing between copulation and fertilization
• Embryonic diapause permits flexible timing between fertilization and the completion of embryonic development
• Embryonic diapause and other forms of diapause are common in insects
• Delayed implantation and postpartum estrus play important timing roles in mammals
• Some iteroparous animals reproduce only once a year

Sex Change

Reproductive Endocrinology of Placental Mammals

• Females ovulate periodically and exhibit menstrual or estrous cycles
• Males produce sperm continually during the reproductive season
• BOX 17.3 Sex Determination and Differentiation, Emphasizing Mammals
• Pregnancy and birth are orchestrated by specialized endocrine controls
• Lactation, a costly part of reproduction, is governed by neuroendocrine reflexes

Copyright 2016 Sinauer Associates