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

Biological Communities: The Biome Concept

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?

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

Aquatic habitats

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

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

Lakes can be poor or rich in nutrients. OligotrophicEutrophic Limnology = study of freshwater habitats

Abyssal zone Ocean zones differ in temperature, depth, light, and tides.

Ocean habitats Oceanography Marine biology

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

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

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

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

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 *** Review of major biomes … (write these down)

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

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

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

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

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 Answers

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

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

Climate is the major determinant of plant distributions. Other factors are soil, fire, grazing, topography.

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

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

What is clue that this is a desert?

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

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

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

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

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

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

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

Localities worldwide with similar climate have the same biome.

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

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

Prediction: then unrelated organisms in similar environments will evolve similar form and function = Convergent evolution MexicoKenya

Unrelated African and South American rainforest mammals show striking convergence.

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

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?

Vocabulary

loticlenticplant form herbaceous graminoidstopography continental driftrain shadowmidden ecotonemarineswamp cypressmangrovebog/fen marshsalt marshestuary oligotrophiceutrophicoxbow lake deep sea ventkelp forestinter-tidal community zone More vocabulary…Chaper 5/ Lecture 2: