G2: Ecosystems & Biomes

1. G2: Ecosystems & Biomes (4 hours)

3. G.2.1 Define • gross production • Total amount of energy trapped in organic matter produced by plants per area per time (kJ) • net production • Gross production – energy lost through respiration • Biomass • Dry weight of an organism (g m-2 yr -1)

4. G.2.2 Calculate values for gross production and net production using the equation: • gross production – respiration = net production • GP – R = NP • Sample question!! • Calculate % of energy moving up to herbivores

9. G.2.3 Discuss the difficulties of classifying organisms into trophic levels. • Food webs give more realistic image of ecosystem • Omnivores especially difficult-- • Depending on what eating, can be 1/2/3 consumer at different times

11. G.2.4 Explain the small biomass and low numbers of organisms in higher trophic levels. • Top predators must be large enough to overwhelm their prey, so can only be relatively few of them • Higher trophic levels: low total biomass per unit area of ecosystem • Biomass lost during respiration @ each TLevel • Cell respiration: biomass of glucose is lost, CO2, Water excreted • Each successive level loses more and more biomass

14. G.2.5 Construct a pyramid of energy, given appropriate information. (Xref- pyramid of energy- 5.1.12) • Trophic Level Energy Flow (kJ m–2 yr–1) producers 20,810 primary consumers 3,368 secondary cons. 383 tertiary consumers 21

18. G.2.6 Distinguish between primary & secondary succession, using an example of each. • CHANGE in abiotic and biotic factors in ecosystem over time...some species gradually replace others in a particular area • Primary: • Previously barren, lifeless area • Newly created volcanic island • Pioneer species usually lichens—tolerant to extreme temp changes and little/no soil; they decompose rock...soil forms • moss can survive  seeds germinate  coconuts wash ashore, germinate; animals may swim/fly/carried on floats from other islands

19. Secondary: follows natural or artificial “upheaval” of the primary succession • MUCH faster b/c soil already present, may be existing seeds & roots • Ex. Forest fire

22. G.2.7 Outline the changes in species diversity and production during primary succession. • OVERALL TRENDS: • Few species to many • Pioneer species to those that compete with others for nutrients • Little to high diversity (mature forest is home to 100s species) • Simple relationships to more complex (mutualism, competition, predation) • More & more biomass at each stage of succ.

23. G.2.7 Outline the changes in species diversity and production during primary succession. • Foredune: no soil, only sand, p.succ. Starts here—lyme grass very salt tolerant, fast growing, roots stabilize dune; marram grass too, wide roots. LITTLE PLANT DIVERSITY • Yellow dune: developing thin layer of soil b/c yrs of m.grass; more plants invade (sedge, etc); rabbits here, nutrients from poop ; summer dandelions/thistle. Humus builds as pioneers decay. MORE COMPLICATED, MORE SPECIES, SOIL BEING FORMED

24. G.2.7 Outline the changes in species diversity and production during primary succession. • Grey dune: yrs of plants dying/decomposing, so layer of humus; it holds water; dune farther inland, less salt; thick shrubs eventually grow here • Mature dune: final stage of succession. • Can support a forest • Wild flowers, trees, mosses/ferns in shade • Thick humus b/c 200 yrs of plants; high moisture content • Many insects, birds, mammals • Cooler temp than foredune; less wind/blowing sand

25. G.2.8 Explain the effects of living organisms on the abiotic environment with reference to the changes occurring during primary succession. • soil development • Death/decay of plants/animals  humus • Quickly absorbs and releases water, good for plants • Leaf litter creates more org matter, mixes with sand, creates deep, well-draining soil; can support tall trees • accumulation of minerals • Sand doesn’t hold moisture but humus & soil do, takes time to get structure to hold moisture and minerals to allow aeration of roots (structure IMPROVES) • Bacteria, fungus (decomposers) active in recycling nutrients in soil w/humus (recycling INCREASES) • reduced erosion • Roots stabilize dune/soil, reduces erosion

27. G.2.9 Distinguish between biome & biosphere. • Biosphere: living part of earth (where organisms live) • Crust, atmosphere • Biomes: divisions of biosphere • Each is part of biosphere • Defined by community structure and vegetation

28. G.2.10 Explain how rainfall and temperature affect the distribution of biomes. • A climograph showing the biomes in G.2.11 can be used to illustrate the interaction between these two factors. • PLOTS temp and rainfall in a region • Tundra: organisms adapted to cold, dry • Conif forest: plants conserve water when ground frozen, animals heavy coats in winter (summer-shed) • Temp forest: wide range of conditions (many deciduous to reduce water loss in winter) • Desert: specific adaptations for extreme heat and dryness (kangaroo rat’s specialized kidney; cacti’s spines) • Trop forest: high temp, high rainfall

29. G.2.11 Outline the characteristics of six major biomes.

30. G.2.11 Outline the characteristics of six major biomes.