Term
| How is the European Starling (bird) affected by photoperiod)? |
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Definition
| Longer days --> gonadal recrudescence |
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Term
| Endogenous circannual rhythm is entrained by photoperiod...but transition to anestrus (gonadal regression) depends on... |
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Definition
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Term
The following environmental cues affect what animals' reproductive cycles?
Photoperiod
Temperature
Moisture
Lunar cycle |
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Definition
Photoperiod - mammals, birds, reptiles
Temperature - amphibians, reptiles
Moisture - amphibians, reptiels
Lunar cycles - fish |
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Term
| T/F: Fall post-breeding migrations are more synchronized than spring migrations. |
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Definition
| FALSE - Spring migrations associated with breeding more synchronized than fall post-breeding migrations |
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Term
What leads to precocious gonadal development in migratory birds?
What does precocious gonadal development cause in migratory birds? |
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Definition
Increased photoperiod
--> PRL release--> premigratory fattening
and --> GnRH release |
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Term
| What increases premigratory restlessness (locomotor activity and searching behavior) in birds? |
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Definition
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Term
What is water drive? and what is another name for it?
What hormone controls water drive?
What inhibits it?
What environmental factors promote it? |
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Definition
Water drive in newts, aka second metamorphosis, is when the newts migrate back from the forest to their native pond to reproduce.
PRL stimulates it, thyroid hormone inhibits it.
Skin becomes secretory in preparation for life in aquatic environment.
Rain and temperature factor in as well. |
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Term
| Explain phenotypic plasticity |
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Definition
Property of a given genotype to produce different phenotypes in response to distinct environmental conditions (Nilsson-Ehle, 1914)
...how phenotype develops in relation to environment. |
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Term
| Explain developmental plasticity |
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Definition
Term used to recognize that phenotypic plasticity is often (but not ALWAYS) a developmental phenomenon.
...development not just genes. |
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Term
| Prey-induced polyphenism in salamander larvae |
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Definition
| Larger head size, more muscles, bigger jaws - induced by flapping of tail |
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Term
Predator-induced polyphenism in tadpoles
What blocks these affects? |
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Definition
Increased corticosterone-->deeper tail
Can be induced by corticosterone injections
Metyrapone (MTP) blocks corticosteroid synthesis |
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Term
How do the tail heights compare for
Predator cue
CORT injection
Predator cue + Metyrapone
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Definition
Tail deepest with predator cue
then CORT injection
then predator cue + Metyrapone
(predator cue + metyrapone still deeper than control) |
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Term
| What hormone responds to the drying up of a pond and speeds up metamorphosis for tadpoles? |
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Definition
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Term
| Potent TSH-releasing facotr in non-mammalian species |
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Definition
CRF
Also accelerates metamorphosis
***
CORT can accelerate TH induced tail regression |
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Term
In fetus, CRF signals to _____ to produce _____ which crosses the placenta and gets converted to _____.
That induces 3 important things: |
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Definition
In fetus, CRF signals to fetal adrenal cortex to produce androgens which crosses the placenta and gets converted to estrogen.
Estrogen induces:
Increased oxytocin receptors
Increased production of connexins in uterus
Increased prostaglandins produced by decidua which acts at cervix to induce expression of collagenase enzyme. Collagenase breaks down collagen fibers and causes cervix to "ripen"
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