incubation and development

incubation and development - Incubation and Development All...

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Incubation and Development All egg-laying vertebrates control egg temperature in some way. Birds are the only ones that have a direct transfer of body heat incubation behavior is important
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Length of Incubation 1. Egg Mass (single most important factor determining incubation time) - larger eggs take longer to hatch 10 – 14 days in small passerines 10 – 12 weeks in albatrosses Why ? Developmental rate tends to be constant; slowly- growing birds grow slowly inside and outside the egg Large birds grow more slowly than small birds Large birds lay large eggs
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Length of Incubation 2. State of Development at Hatching Precocial birds have longer incubation time than altricial birds. (There is a tradeoff between how much development takes place inside vs. outside the egg.) Going along with this… 3. Relative amount of yolk Eggs with more yolk (precocial) have longer incubation time. (Hatch out with 40% of yolk in belly -- a “battery”) Ostrich Robin
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Length of Incubation 4. Ecological Factors Example: Albatross - returns to nest every 2-3 days - food demands kept low by slow growth rate (and, therefore, long incubation)
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Incubation Temperature How chickens like it* Short-term (1 hour) Lethal 42 o C Long-term (many hrs) 40.5 o C 2. Optimal temperature is near upper lethal limit (not much room for error) - beach nesting birds and human disturbance…. mature embryos. much temperature Think “beach umbrella”
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How do we study incubation behavior?
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Data analysis Female leave the nest Female leave the nest Female returned to the nest Female returned to the nest
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ECOLOGICAL FACTORS What Mockingbirds do during high Food availability Treatments Food+ Food-
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incubation and development - Incubation and Development All...

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