WILD 3580 1st Edition Lecture 24Outline of Last Lecture I. Loreal Pit II. Methods of Obtaining PreyIII. Adaptations for SwallowingIV. Reproduction Outline of Current Lecture I. CourtshipII. Delayed Fertilization III. Viparity IV. Extended Parental Investment V. Sex Determination Current LectureI. Courtship- Vision and olfaction o Reptiles use these senses to target chemical cues about specific species and sexual maturityo 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.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 II. Delayed Fertilization - Mating occurs but fertilization is delayed until a later timeo 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 III. Viparity- Oviparouso All turtles and crocodilians o Most snakes and lizards - Ovoviviparous o Some lizards and snakes - Viviparouso 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 Benefits1. Eggs exposed to potential predation for a shorter time 2. Young hatched earlier have a longer time for a growth and fat storage IV. External Parental Investment Low Middle HighTurtles, most snakes and lizards Skinks and Pythons Crocodilians V. Sex Determination - Genotypic sex determination: sex of the offspring is determined at fertilizationo 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 patterns1. Males produced at cooler temperatures; females at warmer temperature (turtles) Pivotal temperature: 50/50 sex
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