LEARNING GOAL:Use data to build a conceptual understanding that the

presence and/or absence of light is important forcontrolling circadian and circannual rhythms

OBJECTIVE: Construct an explanation of how light affects circadian rhythms by analyzing the nature of circadian and circannual rhythms within organisms

Warm Up: Are there any cycles humans have?

• For example, is anything in the environment that triggers feeling tired, hungry, energetic, sleepy, etc.

• Although people don’t respond to environmental cues exactly like plants and animals, they still have cycles that are driven by external factors such as daylight.

Melatonin

• Melatonin is a chemical produced by the pineal gland in the brain. The body produces more when there is less light, which makes humans less alert and more sleepy. Exposure to light decreases the amount of melatonin produced.

The pineal gland is small and located in the brain.

The human biological circadian clock. These times and designations can vary for a given individual

on different days and, of course, among individuals.

QUESTIONS

QUESTIONS

How does your body get you ready for sleep?

What relationships exist between a person’s body functions and the light/dark cycle (24 hours)?

How does your body get you ready for waking up?

When is the optimal time that students should take tests?

When is the optimal time to play sports? BACK

Hypothesize

– Why do you think humans follow a 24-hour circadian cycle?

– You fly in an airplane to Paris, leaving Washington, DC at 4:30 p.m. and arriving in Paris the next day at 8:45 a.m. What effect do you think this will have on your body? Note: Paris is six hours ahead of Washington, DC.

Exploring Organism RhythmsJourney North

• Student Sheet

• Part 1: Examining Photoperiod• Part 2: Exploring Spring 2015 Data• Part 3: Exploring Archived Data Sets• Part 4: Investigating an Organism’s

Relationship to Day Length• Part 5: Going Further

Part 1: Examining PhotoperiodPhotoperiod refers to the amount of sunlight an area receives. Go to the Journey North 2015 Sunlight and Seasons Information Map at http://www.learner.org/jnorth/maps/photo_spring2015.html (or scan the QR code), which shows the reported amount of day length across the United States.

Figure 1. 2015 Sunlight and seasons information map.

What pattern do you see on November 1? The photoperiod or day length decreases with increasing latitude. Now select May 1 from the dropdown calendar. What pattern do you see?The photoperiod or day length increases with increasing latitude.

Part 2: Exploring Spring 2015 Data

Go to http://www.learner.org/jnorth/maps/galleries/2015/spring.html (or scan the QR code) You will be exploring data collected during the spring of 2015.

Figure 2. Spring 2015 Journey North data

Select one of the following organisms to investigate: robins, earthworms, common loons, singing frogs, or barn swallow. Note: Selecting the word “home” that appears underneath each map will lead to more information about the featured organism. Select the map for your organism. What do the dates of the sightings tell you about your chosen organism? The season progresses the organism is spotted in more northerly locations.

Homework

• Natural light is important to more than just behavior. Investigate the relationship between natural light and Vitamin D.

Exit Card

• Write a response to the following question: How does light affect circadian rhythms?

LEARNING GOAL:Use data to build a conceptual understanding that the

presence and/or absence of light is important forcontrolling circadian and circannual rhythms

OBJECTIVE: Construct an explanation of how light affects circadian rhythms by analyzing the nature of circadian and circannual rhythms within organisms

Warm Up: How have this weeks lessons modified your ideas for your sleep study project?

Part 3: Exploring Archived Data SetsGo to https://www.learner.org/jnorth/maps/archives.html(or scan the QR code) to explore additional data sets and interactive maps.

Figure 3. Past seasons data from Journey North.

Under the box that says “Spring 2014 Sightings,” select the link to “Spring 2014 Maps.” You will go to a page that features 22 maps, some static and others interactive. The maps represent observable events related to plants, animals, and weather. Each of the selections contains a map, a list of reported sightings, and a background page about the species. Select an organism whose behavior you would like to explore further. Note: Do NOT select symbolic monarchs, whooping cranes, signs of the seasons, or habitat projects. Select the map for your organism. For some organisms, such as the Monarch butterfly, you can filter the results by selecting various dates.

Part 3: Exploring Archived Data SetsGo to https://www.learner.org/jnorth/maps/archives.html(or scan the QR code) to explore additional data sets and interactive maps.

Figure 3. Past seasons data from Journey North.

Examine three years of sightings for your organism. Describe any similarities and/or differences between the maps. Things to consider:

Is the activity level of your species (e.g., migration) similar each year? If yes, what factors would trigger an organism to react in the same way each year?

Is there a specific week or month of maximum sightings?

Part 4: Investigating an Organism’s Relationship to Day Length

Figure 4. Map showing data collected of frogs first heard singing.

Using either the current season or past seasons, develop a question to explore related to an organism’s activity and day length. For example, Is there a relationship between day length and the first frog heard singing? You will then use the maps to answer your question. The maps will provide evidence for your answer. Figure 4 is an example of how to answer the question Is there a relationship between day length and the first frog heard singing. It shows that as day length increases, more frogs could be heard singing. In addition, frogs in more northern regions begin singing later in the spring. This is due to colder temperatures.

Part 4: Investigating an Organism’s Relationship to Day Length

Figure 4. Map showing data collected of frogs first heard singing.

Using an organism of your choice, develop a question to investigate to determine how day length impacts the organism. Use the maps from the Journey North website to answer your question. Your question: What patterns do you notice? What do you think is happening and why? What is your hypothesis? What did you find out when you investigated your question? What other explanations could be plausible (i.e., an alternative hypothesis)?

Part 5: Going FurtherWhat other types of behaviors do you think are linked to day length or the amount of light organisms receive? Use the Journey North site to support your ideas.

Below are some questions to consider:

When did your chosen organism begin to migrate? Note: Not all species migrate.

Was there a peak week during which your selected organism was spotted?

Is the activity of your organism linked to the availability of food and/or habitat? For example, what is the relationship between: Monarch butterflies and milkweed? Between robins and earthworms? Between leaf out and orioles? The study of seasonal changes shown by plants and animals is called phenology. As the climate gets warmer, organisms are moving farther north. Many plants are now blooming earlier than they used to in the past. What effect will this have on types of birds that depend on plants for seeds and fruit? The birds are out of sync with their food supply. This may impact their ability to successfully raise their young