The document provides an overview of different ecosystems and biomes. It discusses key characteristics of different terrestrial biomes including tundra, deserts, boreal forests, temperate deciduous forests, grasslands, savannas, Mediterranean shrublands, tropical dry forests, and tropical rainforests. It also covers primary and secondary succession and examines factors that influence ecosystem types such as precipitation, temperature, soil type, and climate patterns.

1. Announcements March 7, 2011 Exam 1 results are in! Please see your TA if you want to go over your exam In discussion this week: Global Climate Change Water Use vs. Distribution

2. Exam 1 distribution Mean = 87

3. Types of Ecosystems I & II Lecture Objectives: Understand Succession Learn the characteristics of the major ecosystems

4. Recurring Themes… Terrestrial vs. Aquatic Type of ecosystem influenced by: rock/soil type temperature precipitation producers/consumers surrounding ecosystems time

5. Community Properties Abundance -Total number of organisms in a community. Diversity - Number of different species, ecological niches, or genetic variation. As a general rule, diversity decreases when moving from the equator to the poles Don ’t forget, its not only about the number of species but also the number of interactions…

6. Succession - communities proceeding through predictable changes through time

7. Succession Outcome is a climax community - stable, long-lasting community

8. Two types of succession Primary - begins with total lack of organisms, bare mineral surface bssv01.lancs.ac.uk/bs/research/ soilecol/linkgrd.htm Succession following melting of the Muir Glacier

9. Primary succession Starts with bare rock, sand, clay, etc. Colonized by pioneer community First to colonize bare rock Mainly lichens = mutualistic association of algae or bacteria and fungi

10. Primary succession Acids produced by lichens, physical, chemical weathering break down rock Dead organic matter and weathered rock create soil

11. Primary succession Lichens eventually replaced by small, annual plants Replaced by smaller perennial plants: herbs and grasses Replaced by grasses, shrubs, shade intolerant trees Climax forest composed of shade tolerant trees

12. “ Climax” community is not a preordained set of species Rate of succession and kind of climax community determined by: Type of initial substrate Climate Rate of soil accumulation Water availability Temperature

13. Secondary - begins with destruction or disturbance of existing ecosystem Primary takes longer than secondary http://content.lib.washington.edu/mtsthelens/ © Roger del Moral Mount St. Helens 1980 1996 Two types of succession

14. Secondary succession Main difference from primary succession: Results from disturbance to “climax” community - Soil already formed - Pool of species in soil or nearby that can quickly colonize

17. Biomes - climax communities with wide geographical distributions Terrestrial biomes primarily influenced by: Precipitation : total amount per year seasonal distribution form (rain, snow) Temperature : range of temperatures seasonal patterns Other factors: soil type, wind, fire, etc.

18. Precipitation and temperature influenced by latitude, longitude, and altitude

19. % IB 105 students who have visited: Tropical Forest: 26% Prairie or other grassland: 69% Desert: 39%

20. Major Terrestrial Biomes

21. Tundra Occurs at extreme northern latitudes, or high elevations (mountain tundra)

22. Tundra Key characteristics low precipitation (<35cm) Permanently frozen soil layer = permafrost Waterlogged soils common in summer Low evaporation, permafrost Short plants dominate Grasses, dwarf birch, dwarf willow, lichens

23. Desert Key characteristics Very little water (<25 cm/year) High evaporation Large daily temperature fluctuations Species not very dense Species have adaptations to hot, dry environment Plants – small leaves, store water, dormancy Animals – Night activity, conserve water

24. Common myths about deserts: They are nothing but sand Joshua Tree National Park, CA Gobi Desert, Asia Mohawk Dunes, AZ

25. Common myths about deserts: Not much lives there Burrowing animals, rodents, lizards, snakes

26. Common misperceptions about deserts: They are always unbearably hot

27. results from over grazing, intense agricultural use, erosion, water runoff, and over heating of soil. Desertification : change from fertile land to desert.

28. Boreal Forest Also called taiga, northern coniferous forest Occurs in southern Canada, northern Europe, much of Russia

29. Boreal Forest Key characteristics Moderate to low precipitation (25-100 cm) Short, cool summer; Long harsh winters Spruce and fir, dominant vegetation Humid due to precipitation and low evaporation, but winter dry because precipitation is snow

30. Temperate Deciduous Forest Occur in eastern half of U.S., south central and eastern Canada, southern Africa, Europe, Asia

31. Temperate Deciduous Forest Key characteristics Moderate rainfall (75-100 cm), relatively evenly distributed Warm summers and relatively mild winters Trees dominant vegetation, type of tree varies geographically In North America, dominant trees are maples, aspen, oaks, hickories, etc.

32. Grasslands Occur in temperate areas Also called prairies or steppes

33. Grasslands Key characteristics Medium precipitation (25-75 cm) Hot summers, cold to mild winters Grasses dominant vegetation Need fire to prevent invasion of trees, release nutrients

34. Grasslands Key characteristics Lots of grazing animals Wastes fertilize prairies, grazing helps keep out trees Most grassland has been converted to agriculture

35. Savanna Occurs in Africa, South America, Australia Key characteristics High rainfall (50-150 cm), but unevenly distributed Periods of high rainfall, followed by droughts Temperature warm, relatively constant

36. Savanna Key characteristics Plants dominated by grasses and drought resistant trees Dominant animals are grazers Plant and animal reproduction timed around rainy season, when resources least limiting

37. Mediterranean Shrublands Also known as Chaparral . Receives 40-100 cm annual precipitation. Wet, cool winters and hot, dry summers. Typical of Mediterranean coast and coastal southern California.

38. Mediterranean Shrublands Vegetation dominated by woody shrubs adapted to hot, dry summers. Fire is a common feature.

39. Tropical Dry Forest Annual precipitation ranges 50-200 cm. Many exhibit monsoon climate. Rainfall highly seasonal. Drought resistant plants.

40. Tropical Rainforest Occur along equator in Central and South America, Africa, Southeast Asia, Caribbean and Pacific Islands

41. Tropical Rainforest Key characteristics Temperature warm and relatively constant Very high rainfall (>200 cm/year) Rapid growth, but nutrient poor soils Multi-layered forests of emergent trees, canopy trees, understory trees, shade-tolerant plants, and epiphytes Most diverse biome on earth