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Questions and Answers
What is one adaptation that organisms have evolved to cope with winter's challenges?
What is one adaptation that organisms have evolved to cope with winter's challenges?
How do animals often regulate their reproductive behavior?
How do animals often regulate their reproductive behavior?
Which species is known for having a gestation period of 150 days and breeds in autumn?
Which species is known for having a gestation period of 150 days and breeds in autumn?
What triggers seasonal responses in many animals and plants?
What triggers seasonal responses in many animals and plants?
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What is a common reproductive strategy for spring-breeding small rodents?
What is a common reproductive strategy for spring-breeding small rodents?
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What function does coloration serve for certain winter organisms?
What function does coloration serve for certain winter organisms?
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How do biological clocks relate to environmental cycles?
How do biological clocks relate to environmental cycles?
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Which plant or animal is a long day breeder with a 21-day gestation period?
Which plant or animal is a long day breeder with a 21-day gestation period?
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What was the primary experimental setup used in the Nanda-Hamner Resonance Experiment?
What was the primary experimental setup used in the Nanda-Hamner Resonance Experiment?
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Which concept does the experimental design of the Nanda-Hamner Resonance Experiment primarily test?
Which concept does the experimental design of the Nanda-Hamner Resonance Experiment primarily test?
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What would be the correct classification of the birds' response if they exhibit a reaction to two 8-hour light pulses?
What would be the correct classification of the birds' response if they exhibit a reaction to two 8-hour light pulses?
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What is the significance of the intervals of darkness between the light pulses in the experiment?
What is the significance of the intervals of darkness between the light pulses in the experiment?
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Which model is being evaluated through the light pulse intervals in the context of the experiment?
Which model is being evaluated through the light pulse intervals in the context of the experiment?
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How does the earth's tilted axis affect the seasons?
How does the earth's tilted axis affect the seasons?
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Which photoperiod configuration represents a long-day condition?
Which photoperiod configuration represents a long-day condition?
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What does the term 'critical photoperiod' refer to?
What does the term 'critical photoperiod' refer to?
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Which model is associated with Erwin Bünning in relation to photoperiodism?
Which model is associated with Erwin Bünning in relation to photoperiodism?
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What is the function of the circadian system in plants?
What is the function of the circadian system in plants?
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What distinction does the Hourglass Model make in photoperiod responses?
What distinction does the Hourglass Model make in photoperiod responses?
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What unique characteristic differentiates long-day from short-day responses?
What unique characteristic differentiates long-day from short-day responses?
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What is one main limitation of relying solely on seasonal changes for predicting annual phases?
What is one main limitation of relying solely on seasonal changes for predicting annual phases?
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What is the term used for the phase in photoperiodism that is not illuminated?
What is the term used for the phase in photoperiodism that is not illuminated?
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What role does latitude play in the annual cycle of day length?
What role does latitude play in the annual cycle of day length?
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What regulates GnRH secretion in the anterior pituitary gland?
What regulates GnRH secretion in the anterior pituitary gland?
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Which cells are referred to as tanycytes?
Which cells are referred to as tanycytes?
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How does the photoperiodic signal affect TSH secretion in mammals?
How does the photoperiodic signal affect TSH secretion in mammals?
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In birds, where does the light information for TSH secretion come from?
In birds, where does the light information for TSH secretion come from?
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What does the duration of the pineal melatonin signal regulate in mammals?
What does the duration of the pineal melatonin signal regulate in mammals?
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Which factor is primarily responsible for regulating seasonal reproduction in both birds and mammals?
Which factor is primarily responsible for regulating seasonal reproduction in both birds and mammals?
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Which statement about TSH in mammals is correct?
Which statement about TSH in mammals is correct?
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What role does thyroxine play in photoperiodic time measurement?
What role does thyroxine play in photoperiodic time measurement?
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What characterizes a circannual clock?
What characterizes a circannual clock?
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In the context of circannual rhythms, what environmental factor primarily entrains the clock to a 12-month period?
In the context of circannual rhythms, what environmental factor primarily entrains the clock to a 12-month period?
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What is the primary difference in TSH secretion between mammals and birds?
What is the primary difference in TSH secretion between mammals and birds?
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What observation would likely hold true for golden-mantled ground squirrels raised in constant light and temperature conditions?
What observation would likely hold true for golden-mantled ground squirrels raised in constant light and temperature conditions?
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How long is the free-running period of circumannual clocks observed in many species?
How long is the free-running period of circumannual clocks observed in many species?
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What effect does artificial lighting have on human life according to Roenneberg and Aschoff?
What effect does artificial lighting have on human life according to Roenneberg and Aschoff?
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In the context of photoperiodism, what conclusion can be drawn regarding humans?
In the context of photoperiodism, what conclusion can be drawn regarding humans?
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What role does melatonin play in lower mammals that raises questions about its use in humans?
What role does melatonin play in lower mammals that raises questions about its use in humans?
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What was the focus of the Nanda-Hamner experiment involving white-crowned sparrows?
What was the focus of the Nanda-Hamner experiment involving white-crowned sparrows?
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Which of the following years did not feature the collection of conception rate data, based on the provided periods?
Which of the following years did not feature the collection of conception rate data, based on the provided periods?
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Study Notes
BSci 3230 - Important Information
- These files are solely for BSci 3230 student use for exam preparation.
- Sharing these files with individuals outside the class or using them for any other purpose is prohibited.
- Copyright material may be included; unauthorized distribution is not permitted.
Animal Photoperiodism & Circannual Rhythms
- Annual cycles are influenced by photoperiod (day/night length).
- Evidence suggests circadian systems measure day length, using a Photoperiodic Time Measurement (PPTM).
- Melatonin acts as a signal for PPTM.
- Circannual cycles have effects on animal yearly activity.
- Human influence on these cycles is also a subject of the topic.
Annual Hibernation
- Annual hibernation is a subject for study in BSci 3230.
Annual Migration
- Annual migration patterns are covered in BSci 3230.
Seasonal Diapause
- Seasonal diapause is a phase of suspended development in the Southwestern Corn Borer (Diatraea grandiosella).
- This includes the spring and fall phenotypes.
Photoperiodism in Plants
- Photoperiodism, the response to day length, was first observed in plants.
- Tobacco, often a long-day or day-neutral plant, is a prime example in BSci 3230
- Research by Garner and Allard (1920) investigated the effects of day/night length on plant growth and reproduction, focusing on tobacco.
- Experiments explored the effects of different light and dark durations on flowering in specific varieties of tobacco.
Building a Seasonal Clock
- Organisms use behaviors and physiological adaptations to conserve energy during winter.
- Examples include hibernation, increasing fur/body size, avoiding predators, timing reproduction, or migration.
Tracking the Seasons
- Animals' coloration, like ptarmigan's, and reproduction are tied to seasons.
- Examples include soay sheep and Siberian hamsters
- The onset of breeding is often controlled by gestation time, with variations between species (e.g., sheep, deer in autumn; small rodents/birds in spring).
- Many animals (and plants), regulate their reproduction and physiology seasonally using circadian clocks to measure day length and trigger responses
Photoperiodic Time Measurement (PPTM)
- Photoperiodism is the measuring of day-length.
- The circadian model, proposed by Erwin Bünning in the 1930s, describes photoperiodism. This model is often now referred to as the "External Coincidence Model".
- The concept of a "critical photoperiod" is introduced.
- Bünning's Hypothesis and the Hourglass Model provide explanations of how day length affects responses in plants and animals.
- Experiements, like the Nanda-Hammer Resonance Experiment and the T-cycle Experiment, were designed to study these response mechanisms.
Photoperiodic Time Measurement (PPTM) and Melatonin
- Pineal melatonin production in the topic of photoperiodism.
- Melatonin production is high at night and is impacted by light levels, which is part of the regulation in annual cycles.
- Studies show differences in melatonin profiles across species, across seasonal changes and between long/short days.
- Melatonin levels are affected by the length of the night and influence seasonal photoperiodic responses; particularly the duration of the melatonin signal is a key part of annual cycles of animals.
Anatomical Sites of Photoperiodic Time Measurement (PPTM)
- The SCN (suprachiasmatic nucleus), the pineal gland, and the pituitary gland are involved in the PPTM process.
- The process of photoperiod information is carried through the Retina, via the Optic Chiasm to the SCN.
- Melatonin plays a part in influencing seasonal responses and encoding night length.
Circannual Clocks
- Circannual clocks are adaptations to seasonal changes that do not directly require seasonal changes for their timing.
- Circannual cycles usually last 10-12 months, and are in animals.
- Examples include the golden-mantled ground squirrel and stonechats.
- Environmental factors, like day length, influence the timing of these cycles.
Annual Migrations and Sun-Compass Orientation in Birds and Butterflies
- Monarch butterflies and birds use the circadian clock for migration and navigation.
- Migrations' timing and directionality are influenced by environmental changes during the year, including the different seasons, and the clock is impacted.
Seasonal Cycles in a Migrating Bird's Life
- Seasonal changes in a bird's life, like molting, fattening, and breeding/migration are discussed
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Description
This quiz covers key concepts in photoperiodism, circannual rhythms, annual hibernation, and migration as part of BSci 3230 exam preparation. It focuses on the influences of photoperiod and the biological mechanisms driving these annual cycles in animals, including human impacts. Understanding these topics is essential for students preparing for exams in this course.
