1. Biomes

2. What are biomes?
Large, distinctive areas created and maintained by climate.
Major regional community of plants and animals with similar life forms and environmental conditions.
Biomes are named after the dominant life form such as grassland or tropical rainforest.

3. Biomes can be found at certain latitudes.
The major biomes are widely distributed and their distribution is primarily a product of climate and soil types. Most biomes cover large areas and occur on more than one continent.

4. Look back at the map to find the latitude of each biome.
Tundra
Taiga
Temperate Deciduous Forest
Scrub forest (Chaparral)
Grassland
Desert
Tropical Rainforest
Temperate Rainforest
Biologists have no idea whether the lakes and oceans of the world can be organised into one biome or a hundred biomes.

5. Tropical Rainforests
Deserts
Temperate
Forests
Tundra

6. Biomes are determined largely by climate
Temperature
Precipitation
Insolation (solar radiation)
Distribution is obvious – where your biome can be found in the world.
Productivity – consider diversity of animals and plants and consider differences in times of the year (growing seasons vs non-growing seasons).
Climate - Where precipitation is abundant (100cm or more per year) and is fairly evenly distributed, the major determinant is temperature. It is not simply a matter of average temperature. Consider whether your biome is established by rainfall or by temperature or by another factor.

7. What generates Earth’s climatic regions?
The Earth heats unevenly due to uneven way sunlight hits our planet.
The tropics are warm and the poles are cold because the sun heats Earth’s surface unevenly. Like a flashlight beam shining directly down onto the table from above versus one coming obliquely from the side, sunlight hitting Earth directly is more intense than sunlight striking at an angle.
The precise angle the sun makes at a point on the glove depends on the distance between the point and the equator (the latitude) and the season.

8. Climate: Insolation (incoming solar radiation)
The Earth’s rotation.
Temperatures fluctuate with the seasons because our planet spins on an axis tipped at a constant tile relative to the sun. Consequently, during summer, the Northern Hemisphere inclines maximally toward the sun, and receives more sunlight, while in winter, it tips away from the sun and receives less sunlight. The seasons are reversed in the Southern Hemisphere. This uneven illumination caused by Earth’s tilted axis helps explain the warm temperatures and abundant growth of organisms in summer and the cold temperatures and dormancy of living things in winter.

9. Climate: Precipitation.
Sunlight striking the Earth heats the air. Warm air has different properties than cool air, and these account for the formation of rain and snow. Cold air weighs more than warm air, by volume, and so tends to sink. Dense, cool air holds less moisture than light warm air.

10. Powerful sunlight hitting the equator heats the air, which picks up moisture by evaporation from land surfaces and plant leaves. The hot, moist air rises and once aloft, cools, releasing water it can no longer hold as rain, onto the lush tropical tropical forests.

11. Go back to the slide before to see why..
The equator is warm and wet = tropical
Deserts are found around 30o latitude
Temperate forests and grasslands are around 45o latitude
Tundra is found at 60o latitude

12. What are limiting factors?
Limiting factor - the factor which limits the growth of a population because there is too little or too much of it in the environment.
Biomes and ecosystems are shaped by limiting factors.
Any species has a certain range of tolerance to these factors (tolerance thresholds) which set that species’ range and potential population.
Every organism needs certain requirements for its survival. There are several limiting factors which determine whether an organism can live in a particular environment.
Abiotic environment are things like sunshine, climate (temperature and precipitation) and nutrients from the solid earth (rocks and soils).

14. Tropical rain forests: 0-10o latitude

15. Tropical Rainforests 365 days of sunlight Year round growing seasons
Warm temperatures year round
Abundant rainfall
The most productive biome
Poor soil

16. Tropical soil is low in organic matter and tends to be oxidized.

17. Deserts: 30 north and south of the equator

18. Desert biomes Abundant sunshine Temperature varies Extremely low
Precipitation
Low productivity
Water is the
limiting factor

19. Desert soils are low in organic matter as they have little vegetation

20. Temperate Forest Biomes

21. Temperate forests Cold winters Warm wet summers
Growing season only in summer months
Leaves fall in autumn
Soil high in organic
matter
Productive farm land

22. Temperate soil profile

23. Temperate Grasslands Cold winters Spring rain Warm summers
Dry in late summer
Grass becomes dormant in winter and adds organic matter to the soil.
Soil is fertile from build up of organic matter (good topsoil for agriculture)

24. Temperate grassland soil profile

25. Chapparal /Mediterranean Biome

26. Chaparral (Mediterranean)
Hot, dry summers
Mild winters with
Moisture
Like Santiago

27. Taiga, boreal forest, coniferous forest

28. Taiga

29. latitudes 55°  to 70° North

30. Tundra Cold, dark winters Short growing seasons Permafrost
Low productivity

31. Arctic Tundra

32. Tundra soil profile

33. Permafrost

34. Things to remember: The climate determines the biomes
Biomes are mainly located along lines of latitude on the planet
Productive biomes have longer growing seasons than less productive biomes
Temperate biomes have good conditions for soil formation

35. Be able to: Link biomes to agriculture
Link biomes to carbon dioxide intake of growing plants
Link biomes to soil formation