ANSWERS TO COMPREHENSION TESTS AND DISCUSSION QUESTION FOR MIGRATION LESSON PLAN
Test on Biome Migration Among Birds
1. What advantage do birds gain by migrating to the Arctic for the summer breeding season? The answer to this question will count for two points. Suggested Response: Migration allows birds to take advantage of food that is abundant in the summer in the northern terminus of their migration routes and abundant in the southern end of their migration routes during the winter. The summer months in the north produce an explosion of the flying insects, caterpillars, fruits, and nectar on which many species of birds feed. Food that is rich in protein, longer daylight hours, and a greater area over which the birds can spread are some of the advantages of summer in the North. There are also fewer predators in the North than there are in the South. Even near the Arctic Circle the long days and the short temperate season give rise to a fantastic flowering of life. It is the advantage gained from the environment in the North, most importantly the increased access to food that leads birds to migrate. A population that is resident in the southern terminus of a bird's migration route will not have access to such abundant food in the breeding season.
2. What does the Sun have to do with migration? Suggested Response: Migration is a result of seasonal changes and the Sun powers the change in seasons. Specifically, the tilt of the Earth's axis causes certain parts of the Earth to be subject to rays of the Sun that are more direct in summer than in winter.
3. Name two physical features of birds that allow them to fly. Suggested Response: There are three mentioned in the handout: feathers; hollow bones; and magnetic crystals in their brains that they use as a compass.
4. Name two things that every traveler needs in order to find a destination and describe their purpose. Suggested Response: They are a map to show the traveler where to go and a compass to indicate the direction of travel.
5. How can migration of animals be a threat to human health? Give an example. Suggested Response: Birds can carry diseases such as viruses. These can be spread around the world because migrating birds from different areas meet at certain places. Migratory birds are suspected in the spread of the Highly Pathogenic Avian Influenza (HPAI) called H5N1.
6. Describe how ultralight aircraft can be used to reestablish migration patterns in bird populations. The answer to this question counts for two points. Suggested Response: When chicks hatch they "imprint" on the first moving things that they see and hear. To start a migratory flock using ultralight aircraft, eggs are hatched in the northern terminus of the proposed migration route in the spring. The chicks are exposed to the sounds of ultralight aircraft and people wearing costumes to look like adult birds. They imprint on the craft and the costumes. When they have matured enough to fly long distances they will follow the ultralights to their new nesting grounds in the south. On the way, they learn the route and can return to the location where they were hatched on their own. The next year they will repeat the trip without assistance.
7. Describe four of the ways that birds navigate when they fly. Suggested Response:
There are at least five: (1) the Sun, (2) the stars, (3) the Earth's magnetic field; (4) smell; and (5) landmarks.
8. Describe how a residential flock of birds can evolve into a migratory flock. The answer to this question counts for two points. Suggested Response: See Model for the Evolution of a Migratory Flock.
9. Define the term "flyway" and describe the major flyways in North America. The answer to this question counts for two points. Suggested Response: A flyway is a route used regularly by migrating flying animals such as birds, bats, or butterflies. Flyways are like rivers with less important migration routes of individual species feeding into them like tributaries. Flyways in North America are usually broken down into four: the Atlantic Flyway, the Mississippi Flyway, the Central Flyway and the Pacific Flyway. The Atlantic and Pacific Flyways follow the coasts. The Mississippi Flyway follows the path of the Mississippi River and then disburses its birds over the Gulf of Mexico to Mexico, Central America or South America. The Central Flyway is between the Mississippi River and the Rocky Mountains. [Note to teachers: Some biologists find three, combining the Mississippi and the Central, or as many as seven flyways across North America. Any answer which describes these flyways should be accepted.]
10. Give two examples of funnels at which migratory paths of birds converge and describe the geographic features that create them. The answer to this question counts for two points. Suggested Response: Examples in the Guide and their associated geographic factors are: Vera Cruz, Mexico, where the mountains (in which updrafts are not found) and the sea (which has no updrafts) converge, leaving only a 25 mile wide strip of level land through which all of the raptor migration between North America and Central or South America must pass; the Strait of Gibraltar at which the European continent almost touches the African continent; the Dardanelles and the Bosphorus when the European and Asian parts of Turkey meet (otherwise they are separated by the Black Sea and the Sea of Marmara). A fourth funnel is at Falsterbo in Sweden where the Scandinavian peninsula approaches closest to the islands of Denmark which are stepping stones to the European land mass.
11. How does the V or squadron formation help birds to migrate? Suggested Response: The use of this formation by migrating birds saves energy. All of the birds except the leader take advantage of the vortex generated by the flapping wings of the bird in front. In addition, it allows each bird to see the one in front without its progress being impeded.
12. What physiological changes usually occur in birds before they start their annual migrations?
Suggested Response: The birds gain weight, storing energy for the flight.
13. What is the highest birds have been observed? Suggested Response: Bar-headed
Geese have been recorded flying across the Himalayas at 29,000 feet, higher than Mount Everest. Other species seen above 20,000 feet include the whooper swan, the bar-tailed godwit, and the mallard duck.
14. If a migrating bird encounters a head wind, what will it do? Suggested Response: Migrating birds vary their altitude to take advantage of weather conditions and wind currents. To fight a headwind, most birds stay low, where ridges, trees and buildings slow the wind. If they can find a tailwind, birds will ride it as long as possible.
Test on Biome Migration Among Animals Other Than Birds, Nomadism, and Dormancy
1. Chinese Mitten Crabs migrate between three biomes. What are they? Suggested Response: Fresh water, brackish water, and salt water.
2. Name the animal and describe the migration route for the only large land mammal to continue to migrate in the lower 48 states of the U.S. Suggested Response: Pronghorn antelope still migrate in and out of Grand Teton National Park between high mountain summer range and lowland winter range.
3. How long have Caribou been migrating and how far do some of them travel each way? Suggested Response: Caribou have been migrating for more than 27,000 years between summer range in the tundra and winter range in the northern forests. Some Caribou herds travel more than 1900 miles (5000 km) each way.
4. Describe the physical changes that European and North American eels undergo in their migrations and the biomes that they inhabit. This question counts for two points. Suggested Response: In the Sargasso Sea, eel eggs develop into transparent leaflike larvae. They then turn into glass eels and begin to swim upstream in rivers. Once in the fresh water a metamorphosis occurs and the eels change into cylindrical, pigmented bottom-dwellers. Eels live for 10 to 15 years in fresh water, eating insects, worms and small crustaceans. At the end of their lives their bodies change dramatically. Their eyes start to grow and develop optimal vision for dim blue of the clear ocean water. The sides of their bodies turn silvery for camouflage during their long trip back to their spawning grounds. At this stage they are called silver eels. The biomes inhabited by eels are salt water, fresh water, and brackish water.
5. Describe two ways in which eels migrate out of the water. Suggested Response: In their migration eels will crawl across wet grass and tunnel through wet sand for up to 30 miles to reach upstream headwaters and ponds.
6. Describe the migration of gray whales. How far do they migrate and where are their summer and winter grounds? Suggested Response: Gray whales live only in the North Pacific Ocean. They migrate 10,000 to 14,000 miles between summer feeding grounds in the northern Bering Sea to winter calving lagoons off the coast of northern Mexico.
7. How far have Monarch Butterflies been known to fly in their migrations? Suggested Response: Monarchs have been known to fly up to 1800 (2900 km) miles from Ontario, Canada, to Mexico.
8. Which type of reptile migrates the longest of any other reptile and how far have they been known to migrate? Suggested Response: Sea turtles migrate, swimming thousands of miles.
9. Give one example of biome migration in four separate classes of the sub-phylum vertebrata and briefly describe the migration. The answer to this question counts for two points. Suggested Response: The four classes are: insects, fish, mammals, and reptiles. For examples, see the following titles in the Annotated Student Migration Handout: insects, fish, mammals and reptiles. Do not give credit for answers which include "nomadic migrations" described in the section on Nomadism. Obviously there are many more examples than are provided in the Migration Student Handout.
10. What are the three types of human nomadism? Briefly describe them. Suggested Response: Nomadic behavior among humans has been classified into three general types: hunter/gatherer, pastoral, and tinker/trader. Hunter/gatherers go from place to place hunting or gathering fruits, vegetables or grains. Pastoralists take their herds of animals to different grazing areas. Tinker/traders live in association with settled societies providing services to them.
11. What is the inverse of migration and what are the similarities and differences between it and migration? The answer to this question counts for two points. Suggested Response: Dormancy is referred to as the inverse of migration. It is different from migration in that instead of changing biomes to maximize food sources which is the role of most migrations, dormancy is a behavior in which animals remain in their home range to minimize energy use or loss of moisture. However, dormancy is similar to migration in many of its effects. Dormancy, like migration, allows animals to exist in areas in which they would not thrive during certain seasons.
12. The movements of large numbers of locusts and the quadrennial explosion of Norway Lemmings in which some drown themselves in the ocean are the inverse of one another in one important way. What is that? The answer to this question counts for two points. Suggested Response: The movement of large numbers of locusts occurs in lean years. The locusts are traveling from the remote parts of their range where they moved during good years to the traditional habitat. They are imploding. Lemmings are traveling out of their home range which has become overpopulated.
13. The movements of Norway Lemmings and the "nomadic migration" of antelope, zebras and wildebeests on the plains of Africa have one characteristic that is inverse to each other. What is it? The answer to this question counts for two points. Suggested Response: Lemming populations explode outward when overpopulation exhausts food supplies. Antelope, zebras and wildebeests herds of the African plains spread out when food and water are plentiful and then contract towards watering holes in the dry season.
14. Name three different types of dormancy and briefly describe them. The answer to this question counts for two points. Name and describe a fourth for an extra point. Suggested Response: The types of dormancy are (1) hibernation -- a state in which the body temperature drops to near the temperature of the outside and the animal's metabolism slows down dramatically; it is a state close to death; (2) torpor -- body temperature and metabolism drop but not as significantly as in hibernation; animal does not react to many stimuli; (3) estivation -- a summer type of hibernation used to conserve water; and (4) diapause -- used mostly by insect pupae in which the development of the animal stops for a period of time. For more, see Dormancy in the Helpful Background Section.
15. How can dormancy lead to the spread of disease among humans? Give an example. Suggested Response: See Impact on Humans in the Helpful Background Section. There are undoubtedly other types of dormancy which cause illness in human beings.
16. How do hibernators survive a winter? Suggested Response: They usually rely on fat stored during the summer. Rodent hibernators can rely on a stored food supply. Hibernators often protect themselves from cold and predators by hibernating in a den.
17. What is true hibernation like? Include in your description an account of what happens to body temperature and metabolism. Suggested Response: It is a state close to death. The animal's body temperature generally falls to within a few degrees of the temperature outside its body. Heartbeat is slow and barely perceptible, and respiration drops to a few breaths per minute.
18. Are bears true hibernators? Justify your answer. The answer to this question counts for two points. Suggested Response: Bears are not true hibernators because the drop in their body temperature is not huge, and they are able to wake, move around, and eat on warmer days during the hibernation period. Bears do not normally urinate or defecate during their winter torpor, water and nitrogen being re-absorbed in the bladder. A few bears have been known to give birth during the winter and to suckle their young. In fact, if enough is available, bears will forego hibernation. It appears that the lethargy of bears is simply triggered because of the lack of food in the colder months. True hibernation is a state close to death. What happens to bears is really a prolonged state of torpor.
19. Does an animal in torpor react to stimuli from the environment? Suggested Response: Not usually.
20. What is the relationship between hibernation, torpor and sleep? The answer to this question counts for two points. Suggested Response: Torpor is not as extreme as hibernation but even more extreme than sleep. Some scientists view hibernation, torpor and sleep as different levels of a similar phenomena that reduce awareness, slow metabolism and conserve energy. Others point to differences between sleep on the one hand and hibernation and torpor on the other. An animal which is asleep, for example, can dream which is not something than can be done by animals hibernating or in torpor because there is insufficient oxygen and nourishment given to the brain in those states for the animal to dream.
21. Migration of people from one country to another looking for a better life and the annual biome migration of animals use the term "migration" in different ways. What are they? Suggested Response: When people migrate there is no intention of returning and it is hopefully something that is necessary only once in a life-time. It can be for many reasons. People migrate to seek better opportunity, to flee famine, to escape political persecution. Birds migrate every year to maximize their sources of food.
22. Describe how and why magnetotactic bacteria move. Give and support an opinion about whether this is a true migration or true nomadism or something else. The answer to this question counts for two points. Suggested Response: A good response will describe magnetosomes, the anaerobic nature of some bacteria, and how the magnetosomes cause the bacterium to move downward away from more highly oxygenated water. A good answer will note that bacteria do not move between biomes or seek additional food, nor is the activity seasonal. Therefore, the actions of bacteria are not migratory. Nor are they nomadic because the bacteria do not seek food or water. The movement of bacteria appears not to belong to either of the two categories. See Bacteria section of the Student Migration Handout.
23. Are migration, nomadism and dormancy precise terms? Compare them to some other scientific descriptions of nature and tell us how they are helpful. The answer to this question counts for two points. Suggested Response: A good answer will describe these terms as imprecise compared to some other scientific terms but note that the classifications can help us form hypotheses about similar phenomena when they are observed. See Scientific Classifications Are An Attempt to Describe Phenomena in Meaningful Ways in the Student Migration Handout.
Last updated April 19, 2008.
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