Biological Communities: The Biome Concept

1. Assignment: Read Chapter 4:Variations in the Physical EnvironmentNext week ONLY: Monday AM lab = Tues 5-8 Monday PM lab = Wed 5-8Please turn cell phones off + put away. 1st row seats = saved for later-comers…

2. Biological Communities: The Biome Concept

3. OBJECTIVES • What are large-scale distributions of plant life forms? • aquatic • terrestrial • What is the proximal cause of their distribution? • How does climate differ among biomes? • Whittaker’s scheme • Walter’s climagrams • Do form and function converge in regions with similar climate?

4. Concept Map…*** Which physical factor separates habitats? A water availability B movement of water USE EACH ONCE C medium of gas exchange D amount of salinity Biome Terrestrial Aquatic Wetlands Desert Freshwater Marine Rivers Lakes 1 4 2 3

5. Aquatic habitats

6. River: where precipitation > evaporation River continuum Downstream drift High gradient vs. Low gradient

7. A lake can be divided into vertical and horizontal zones. photic aphotic

8. Lakes can be poor or rich in nutrients. Oligotrophic Eutrophic Limnology= study of freshwater habitats

9. Oceanzones differ in temperature, depth, light, and tides. Abyssal zone

10. Ocean habitats Oceanography Marine biology

11. The terrestrial-aquatic interface… Estuary: where a river reaches the ocean but is impeded by landforms

12. The terrestrial-aquatic interface rocky freshwater estuary marine woody herbaceous woody herbaceous swamp bog/fen marsh mangrove salt marsh tropical temperate Another concept map…

13. Concept map*** What 4 variables distinguish biomes? Herbaceous/graminoids Shrubs Trees (grasses, sedges) Shrublands Forests Grasslands Deserts Tundra Evergreen Deciduous Conifers Broadleaf Temperate Trop. Temperate Tropical

14. Biome: a major type of terrestrial community categorized by its 1) dominant plant form, 2) seasonality of leaves, 3) leaf morphology, 4) location.

15. ***Review of major biomes…(write these down) Tropical rain forest Tropical seasonal (deciduous) forest / savanna Subtropical desert Woodland/shrubland Temperate rain forest Temperate seasonal (deciduous) forest Temperate grassland Boreal forest (taiga) Tundra

16. ***What biomes do you see in a cross-country trip from E to W?

17. ***Write down the letter that corresponds to the name of the biome: Pictures not in this PP… go to book to see them.

18. Answers A Tropical rain forestB Tropical seasonal forest/savannaC Subtropical desertD Woodland/shrubland Temperate rain forestE Temperate grassland/desert F Temperate seasonal forest G Boreal forestH Tundra

19. *** Which biome is found at each indicated letter? A B C E D F G H I

20. Answers H Tropical rain forest G Tropical seasonal forest/savanna F Subtropical desert D Woodland/shrubland I Temperate rain forest C Temperate seasonal forest E Temperate grassland B Boreal forest A Tundra

21. ***Proximate/functional approach… • What is the major factor determining biomes? • In one sentence: Why isn’t there a single biome for the earth?

22. Most species have limited tolerance; hence small ranges and biomes develop. ***In one sentence: Compare the ranges of birds/plants.

23. Climate is the major determinant of plantdistributions.Other factors are soil, fire, grazing, topography.

24. Whittaker’s scheme: biomes delineated by average temperature and precipitation.

25. Walter’s climate diagrams allow comparisons among localities. 20 mm monthly rain For each 10ºC in temp = enough water for growth (wherever precip line is above temp line) growing season

26. What is clue that this is a desert?

27. Climatic zones and biomes separated first on basis oftemperature, then precipitation and its seasonality.Boreal + polar climate zones:average annual T=< 5C

28. Temperate climate zones: average annual T = 5-20C

29. Equatorial + tropical climate zones: average T = > 20C.

30. Each climate zone has a typical seasonal pattern of temperature and precipitation. When is its dry season?

31. ***What type of biome would you expect to develop with each climate?Explain. A B

32. ***What type of vegetation would you expect at each locality? Explain. B A

33. ***Summarize in one sentence the main conclusion about biomes based on these figures and legends.

34. Localities worldwide with similar climate have the same biome.

35. Observation:Plant growth form is similar in widely separated areas. I wonder why? Mexico Kenya

36. ***Hypothesis:If form and function match the environment,then…?

37. Prediction: then unrelated organisms in similar environments will evolve similar form and function = Convergent evolution Mexico Kenya

38. Unrelated African and South American rainforest mammals show striking convergence.

39. Example of exam question… Which biome would occur in each climate? What is the limiting climatic factor(s) for each biome? Where is each biome located in the Western (New World) and Eastern (Old World) hemisphere? Put letters on map.

40. OBJECTIVES • What are large-scale distributions of plant life forms? • aquatic • terrestrial • What is the proximal cause of their distribution? • How does climate differ among biomes? • Whittaker’s scheme • Walter’s climagrams • Do form and function converge in regions with similar climate?

41. Vocabulary

42. More vocabulary…Chaper 5/ Lecture 2: lotic lentic plant form herbaceous graminoids topography continental drift rain shadow midden ecotone marine swamp cypress mangrove bog/fen marsh salt marsh estuary oligotrophic eutrophic oxbow lake deep sea vent kelp forest inter-tidal community zone