Lesson 3 The Sun and the Climate
Completion requirements
Earth's Biomes
Scientists have divided Earth into six main biomes.
D2.16 The different biomes of the world
In the previous lesson, you learned that biomes are large areas on Earth that have a common climate and contain the organisms adapted to that climate. Remember, biomes are open systems, meaning that they exchange material and energy with their surroundings. There are not strict boundaries for each biome; instead, biomes slowly change into the next biome. Because of this, there are often transition areas between two biomes, where the characteristics of each biome are mixed. Some scientists label these transition areas as separate biomes. In this course, we will focus on the following six biomes. Let’s look at each biome in detail.
D3.23 Tundra in the summer
Location:
- found in the northern regions of North America, Europe, and Asia
- mostly located in the Arctic Circle
- distinguished by a lack of large vegetation and a hard permanently frozen ground
- few hours of daylight in the winter months; no daylight during the December 21–22 solstice
- cold temperatures: –15 ˚C to 5 ˚C
- small amounts of precipitation (less than 20 cm per year)
- very short summers (about 20 to 30 days on average)
- low insolation and high albedo
- lichens, mosses sedges, and a few woody shrubs
- birds: ptarmigan and birds that migrate during the summer
- small mammals: arctic foxes, snowshoe hares, and lemmings
- herbivores: caribou, reindeer, and musk oxen
- large predators: wolves and polar bears
D3.24 Brown bear in taiga
Location:
- found just south of the tundra biome
- found in North America, Europe, and Asia
- distinguished by large amounts of Evergreen trees
- large variation in length of daylight depending on the seasons
- cool summers and cold winters
- average temperature of –4 ˚C to 14 ˚C
- 40 to 100 cm of precipitation per year, mostly as snow
- longer growing season than the tundra
- more insolation and a lower albedo than the tundra
- evergreens
- lichens and mosses
- birds: woodpeckers, chickadees, grosbeaks, hawks, and eagles
- small mammals: rodents, rabbits, and squirrels
- herbivores: moose
- large predators: bears, lynxes, foxes, and wolves
D3.25 Deciduous Forest in Fall
Location:
- found in North and South America, Europe, Asia, Japan, and Australia
- distinguished by trees that lose their leaves in the fall
- well-defined winter and summer seasons
- large variation in daylight depending on the season
- average annual temperature of 14 ËšC to 24 ËšC
- 75 to 150 cm of precipitation per year
- longer growing season than the taiga
- more insolation than the taiga
- deciduous trees
- mosses, lichens, and ferns
- insects and birds: ground dwelling birds such as turkey and pheasant
- small mammals: squirrels, rabbits, skunks, and chipmunks
- herbivores: white-tailed deer
- large predators: black bears, timber wolves, and red foxes
D3.26 Bison on the prairie in winter
Location:
- found on all continents
- often called prairies (colder) or savannas (warmer)
- distinguished by lots of grasses with a lack of large vegetation
Climate:
- Prairies have winter and summer months, while savannas have wet and dry seasons.
- Prairies have an average annual temperature of 4 ËšC to 18 ËšC, and savannas have an average annual temperature of 18 ËšC to 30 ËšC.
- Both have an annual precipitation of 25 to 57 cm.
- Prairies are mostly used for agriculture and have a longer growing season than colder biomes.
- grasses
- some drought resistant trees in savannas
- some flowering plants in prairies
- birds and insects: hawks, snakes, and reptiles (savannas)
- small mammals: mice, gophers, and rabbits (prairies)
- herbivores: bison, deer, elk, and antelopes (prairies); elephants, giraffes, antelopes, zebras, wildebeests, and rhinoceros (savannas)
- large predators: coyotes, badgers, and kit foxes (prairies); cheetahs, lions, and hyenas (savannas)
D3.27 Savanna during the dry season
D3.28 Toucan in the rain forest
Location:
- found closer to the equator
- found in Central and South America, Africa, Asia, and Australia
- distinguished by large forests and a large diversity of life
- little difference in seasons
- little difference in length of daylight
- average annual temperature of 25 ËšC to 30 ËšC
- more than 200 cm of precipitation per year
- large amount of insolation and low albedo
- largest diversity of plants of all the biomes
- broad-leafed plants
- vines and shrubs
- air plants
- largest diversity of animals of all the biomes
- birds: hummingbirds, parakeets, parrots, and toucans
- small animals: lizards, snakes, and frogs
- herbivores: pacas, agoutis, peccaries, armadillos, and coatimundis
- predators: monkeys, gorillas, jaguars, and tigers
D3.29 Desert in Arizona
Location:
- found in North and South America, Africa, Asia, and Australia
- distinguished by a lack of vegetation
- little variation in seasons
- little difference in daylight
- average annual temperature of 12 ËšC to 27 ËšC, with hot days and cool nights
- less than 25 cm of precipitation per year
- very large amount of insolation and very low albedo
- cacti and drought-tolerant plants
- insects and lizards
- running birds
- small mammals: bats, rodents, and rabbits
- herbivores: antelopes, goats, sheep, and camels
- predators: coyotes, kit foxes, and dingo dogs
Read This
Please read pages 394 to 400 in your Science 10 textbook. Make sure you take notes on your readings to study from later. You should focus on the descriptions of each biome as well as the adaptations seen in plants and animals. Remember, if you have any
questions or you do not understand something, ask your teacher!
Practice Questions
Complete the following practice questions to check your understanding of the concept you just learned. Make sure you write complete answers to the practice questions in your notes. After you have checked your answers, make corrections to your responses
(where necessary) to study from.
- Divide this map (download) into the six biomes.
Your answer should be a variation of the following. The boundaries of each biome may differ slightly, depending on your source.
D2.16 The different biomes of the world
- For each biome, list one reason it would be hard to survive and one adaptation that allows for survival.
Your answer should be a variation of the following:
- tundra: hard to survive: very cold; adaptation: insulating fur coat
- taiga: hard to survive: long cold winters; adaptation: animals hibernate
- deciduous forest: hard to survive: cooler winters with less precipitation; adaptation: trees go dormant by losing their leaves
- grassland: hard to survive: periods of drought; adaptation: plants go dormant during the drought (either winter or the dry season)
- rain forest: hard to survive: lots of plants, so plants that are shorter do not receive as much sunlight; adaptation: plants have very large leaves to catch as much sunlight as possible
- desert: hard to survive: hot, dry days; adaptation: most animals are only active at night when it is cooler and do not need as much water
- Which biome has the greatest insolation? Which has the least? Why?
The rain forest tends to have the greatest insolation, because that biome is found closest to the equator and so receives the most direct sunlight. An argument could also be made for the desert or savanna, as these biomes are also often found close the equator and have a lower albedo, meaning they absorb more sunlight.
The tundra has the least amount of insolation, as it is located the farthest from the equator and as such has the largest angle of incidence. The tundra also does not get sun during the winter solstice, reducing the amount of insolation. The tundra has a high albedo, reducing the amount of the sun’s energy that is absorbed.