WILD 3580 1st Edition Lecture 24 Outline of Last Lecture I Loreal Pit II Methods of Obtaining Prey III Adaptations for Swallowing IV Reproduction Outline of Current Lecture I Courtship II Delayed Fertilization III Viparity IV Extended Parental Investment V Sex Determination Current Lecture I Courtship Vision and olfaction o Reptiles use these senses to target chemical cues about specific species and sexual maturity o Pheromones chemical signal that conveys a message to conspecifics o Displaying dulap and head bobbing Aquatic Turtles o Males have longer claws to use during courtship by vibrating claws on females face Tactile Vision Tortoises These notes represent a detailed interpretation of the professor s lecture GradeBuddy is best used as a supplement to your own notes not as a substitute II III IV V o Chemical communication and vision through stereotype displays movements Snakes o Olfaction and vision o Males participate in a combat dance against each other Crocodilians o Use vocal communications roaring to defend territories and mates Delayed Fertilization Mating occurs but fertilization is delayed until a later time o Sperm is stored in the female reproductive tract Occurs most in marine and freshwater turtles some snakes and lizards o Advantages optimal time for mating may not be suitable to bear young Viparity Oviparous o All turtles and crocodilians o Most snakes and lizards Ovoviviparous o Some lizards and snakes Viviparous o Few lizards and snakes Rate of Development o Related to temperature Ex Eastern Fence Lizard o 23 degree Celsius hatch in 85 days o 33 degree Celsius hatch in 35 days The hotter the temperature the sooner young will hatch Benefits 1 Eggs exposed to potential predation for a shorter time 2 Young hatched earlier have a longer time for a growth and fat storage External Parental Investment Low Middle High Turtles most snakes and lizards Skinks and Pythons Crocodilians Sex Determination Genotypic sex determination sex of the offspring is determined at fertilization o Heterogametic different sex chromosomes Temperature dependent sex determination TSD sex is determined by temperature during incubation Crocodilians many turtles and some lizards Not in snakes o General Mechanism average temperature during the middle third thermos sensitive period of embryonic development When gonads are developing 3 major patterns 1 Males produced at cooler temperatures females at warmer temperature turtles Pivotal temperature 50 50 sex ratio
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