bird ovaries: developing ova inside follicle. oogenesis ovum (gamete) production (meiosis partially...
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Bird Ovaries: Developing Ova inside Follicle
OogenesisOvum (Gamete) Production
(Meiosis Partially Completed at Birth)
Follicle Maturation
Follicle ContainingEgg (= Ovum)
http://www.hiltonpond.org/images/VultureBlackOvum01.jpg
Primary Oocytes: 500 - 2000
Egg (Ovum)
Follicle Maturation
http://www.hiltonpond.org/images/VultureBlackOvum01.jpg
Passerines: 4-5 DaysDucks/Pigeons: 6-8 DaysPenguins: 6-8 Days
Timeframe
Enlargement
Up to 1000X Initial Size
Follicle Maturation:Yolk Contents of Ovum
Materials
• Nutrition (Proteins, Lipids)
• Hormones (e.g., Testosterone)
• Immune Factors (e.g., Carotenoids, Immunoglobins)
• Antioxidants (e.g., Carotenoids,a Vitamin A precursor)
Vitelline Membrane
Yellow Yolk (Day Deposition)
White Yolk (Night Deposition)
Central Latebra (contains clear Vitelline Fluid)
Follicle Maturation:Yolk Anatomy of Ovum
(Germ Spot)
Follicle Maturation:Yolk Content in Altricial versus Precocial Birds
Fig. 14-14 in Gill 2007
Altricial:
Precocial:
http://partnersah.vet.cornell.edu/avian-atlas/sites/agilestaging.library.cornell.edu.avian-atlas/files/avian_atlas_assets/3.4.08.2DSC00050%20x750.jpg
Follicle Maturation: Mature and Atretic Follicles
Stigma ofMaturing Follicle
Atretic Follicles
Ovulation
Clutch
Fertilization
Sex Determination: Birds vs. Mammals
Gynandromorphs
Egg Development: Magnum(Albumin and Chalaza Deposition)
Egg Development: Magnum(Albumin and Chalazae Deposition)
Composition: Water (90%) Protein (10%)
Function: Water Supply Shock Absorption Insulation
Albumin
“Egg Whites”
Egg Development: Magnum
1) Chalazal Albumin (Dense)
2) Inner Albumin (Watery)
4) Outer Albumin (Watery)
3) Fibrous Albumin (Viscous)
Chalaza – Twisted, Ropy Albumin
Egg Development: Isthmus(Additional Albumin, Shell Membrane (2) Deposition)
Egg Development: Isthmus(Additional Albumin, Outer and Inner Shell Membrane
Deposition)
Inner Shell Membrane
Outer Shell Membrane
(Air Space)
Egg Development: Uterus(with Shell Gland)
Egg Development: Uterus (with Shell Gland)
• Additional Albumin
• Shell
• Pigments
Papillae
Fig. 8-76 in Podulka et al. 2004
Function
Fig. 8-66 in Podulka et al. 2004
Egg Development: Uterus (with Shell Gland)(Cuticle, Calcite Crystals, Pore, Shell Membranes, Chorioallantoic Membrane)
Egg Development: Uterus (with Shell Gland)(Consequences of Shell Porosity)
DDT
Egg Development: Consequences of Egg Shell Porosity
Embryo Development: Yolk Sac and 3 Extra-Embryonic Membranes
3) Chorion 3) Amnion 2) Allantoic Sac
Yolk Sac
Egg Development: Shell Gland (Uterus)(Egg Color: Among Species Variation)
24 25
Spotted Streaked
Egg Development: Shell Gland (Uterus)(Egg Markings: Among Species Variation)
Egg Development: Shell Gland (Uterus)(Egg Markings: Among Species Variation)
Fig. 8-76 in Podulka et al. 2003
Egg Development: Shell Gland (Uterus)(Egg Color and Markings: Among Species Variation)
Egg Development: Shell Gland (Uterus)(Egg Color: Within Species Variation)
Individual Egg Recognition in Colonies(Common Murres only accepts eggs colored like its own)
Common Murre
Egg Development: Shell Gland (Uterus)(Egg Markings and Shape – Within Clutch Variation)
American Crow Clutch
(Adaptive Value?)
Egg Development: Shell Gland (Uterus)(Egg Color: Within Species Variation in “Egg-Dumping” Birds)
Female 1
Female 2
Female 3Northern Masked-Weaver
Egg Expulsion: Vagina and Cloaca
Fig. 4-111 in Podulka et al. 2004
Egg Laying• Many Birds (e.g., Passerines, Woodpeckers) Lay Eggs about
24 Hours Apart
• Some Birds Lay their Eggs Two Days Apart (Ostrich, Herons, Doves, Owls, Hummingbirds, Swifts, Kingfishers, Some Accipiters
• Penguins Lay their Eggs Three to Six Days Apart
• Kiwis lay their Eggs 14-30 Days Apart
Egg Size
Egg Size: Among Species Variation
Fig. 8-69 in Podulka et al. 2003
Fig. 8-71 in Podulka et al. 2003
Egg Size: Among Species Variation(Precocious versus Altricial Birds)
Egg Shape : Among Species Variation
Fig. 8-72 in Podulka et al. 2003
Egg Shape : Among Species VariationNomenclature
Fig. 8-72 in Podulka et al. 2003
Egg Shape – Adaptive Value of Shape
Fig. 8-73 in Podulka et al. 2004
Common Murre
Pyriform Shape Adaptive,But NOT FOUND in otherCliff Nesters
28Swift’s Mating