1. Ecosystems & Biomes IB BIO II Van Roekel

2. Assessment Statements G.2.1 Define Gross production, net production, and biomass G.2.2 Calculate values for gross production and net production using the equation gross production – respiration = net production G.2.3 Discuss the difficulties of classifying organisms into trophic levels G.2.4 Explain the small biomass and low numbers of organisms in higher trophic levels G.2.5 Construct a pyramid of energy giving appropriate information G.2.6 Distinguish between primary and secondary succession, using an example of each G.2.7 Outline the changes in species diversity and production during primary succession G.2.8 Explain the effects of living organisms on the abiotic environment with reference to the changes occurring during primary succession G.2.9 Explain how rainfall and temperature affect the distribution of biomes G.2.10 Outline the characteristics of the major biomes

3. Key Terms Species - group or organisms that can interbreed and produce fertile offspring Habitat – the environment in which a species normally lives or the location of a living organism Population – a group of organisms of the same species which live in the same area at the same time Community - a group of populations living and interacting with each other in an area Ecosystem – a community and its abiotic environment. Refers to where a group of interacting populations live. Ecology – the study of relationships between living organisms and between organisms and their environments

4. Key Terms Autotrophs – organisms capable of making their own organic molecules as a food source. Autotrophs are producers (plants, cyanobacteria, etc.) Heterotrophs – organisms that must obtain organic molecules from other organisms (autotrophs or heterotrophs). Referred to as consumers (zooplankton, fish, sheep, etc.) Detritivores – organisms that eat non-organic matter (dead leaves, feces, carcasses). Such as earthworms, woodlice, and dung beetles Saprotrophs - live on or in non-living organic matter, secreting digestive enzymes and absorbing the products of digestion. Fungi and bacteria are saprotrophs, aka decomposers

5. Food Chains & Food Webs Food Chain – sequence showing the feeding relationships and energy flow between species Food Webs – interconnecting series of food chainsd Trophic level – refers to an organisms position in a food chain – T1- Producer; T2- Primary Consumer; T3- Secondary Consumer; T4- Tertiary consumer – Large number of producers and fewer and fewer members of each subsequent level

6. Energy Sunlight is initial energy source for almost all communities. Energy flow occurs as energy is photosynthesized by plants, then transferred to the next level when carbs, proteins, or lipids are eaten and digested by primary consumers, then transferred up the trophic levels Only 5-20% of energy is used from previous step in food chain Majority of energy is lost as heat as it passes from producer to primary consumer to secondary consumer Energy is lost due to cellular respiration, as well as maintenance of organisms

7. Pyramid of energy Shows how fast energy flows from one trophic level to the next in a community (measured in [(kj/m 2 )/year] or kj*m -2 *yr -1 Each level is always smaller than the one before because of the loss of energy.

9. Pyramid of Energy Gross Production – total amount of energy trapped in organic matter produced by plants per area per time in kilojules Net Production – the gross production minues the energy lost through respiration Biomass – the dry weight of an organism measured in g*m -2 *yer -1 Gross production – respiration = net production

10. Example Gross production is 809 kJ m -2 yr -1 Respiration is 729 kJ m -2 yr -1 What is the net production? 809-729 = 80 kJ m -2 yr -1

11. Pyramid of Biomass Similar to pyramid of energy, most at producers, decreases with each trophic level

12. Classifying organisms into trophic levels Eagle can be tertiary or secondary Mouse can be primary consumer or secondary consumer

13. Classifying organisms into trophic levels Grizzly bear can be omnivores, or top predators depending on season, temperature, and ability to forage for food.

14. Ecological Succession Ecological succession is the change in abiotic and biotic factors in an ecosystem over time Primary Succession – begins when plants begin growing on previously barren and lifeless areas (colonization of new volcanic island). Usually begins with lichen, which decompose thin layers of rock. Lichens die and turn to soil, allowing other organisms to grow and survive Secondary Succession – new group of organisms take over following a natural or artificial upheaval of primary succession (recolonization after a forest fire). Much faster than primary succession

15. Primary vs. Secondary Succession PrimarySecondary Begins with no lifeFollows disturbance of primary succession No soilSoil is present New area, e.g. volcanic islandOld area, e.g. following forest fire Lichen and mosses are first plants Seeds and roots already present Biomass lowBiomass higher Low production (increase in biomass or energy) Higher production

16. Species diversity and production in a primary succession Sand dunes are excellent examples of primary succession – Foredune: primary succession starts, no soil, only sand. Marram grass and Lyme grass grow and help stabilize dune – Yellow Dune: dune develops a thin layer of soil from dead and decaying Marram grass. Other plants start to grow, rabbits live here and their feces add nutrients to soil. Humus (part of soil composed of organic matter) builds – Grey Dune: developed layer of humus, which holds water, no sand and thick shrubs grow here. – Mature Dune: can support a forest, including wide variety of plants (wild flowers, mosses, ferns, trees). Thick layer of humus. High moisture content in soil. Large variety of animals as well

17. Development of Primary Succession Few species  Many species Pioneer species  species that compete with others for nutrients Little diversity  high diversity Simple relationship  complex relationships (mutualism, competition, predation) More and more biomass at each stage of succession

18. Living Organisms Change Abiotic Factors Death and decay of plants and animals increases the organic matter or humus in soil (excellent medium for plant growth) Leaf litter and decayed plants creates deep, well- draining soil to support tall trees Plant roots stabilize sand and soil to reduce soil erosion Soil structure improves as humus is formed, holds more moisture, nutrients, and allows aeration of plant roots Bacteria and fungus actively recycle nutrients in soil, increasing fertility of soil

19. Biosphere and Biomes Living part of Earth that contains all the parts where organisms live is called the Biosphere Biomes are divisions of biosphere, defined by vegetation and community structure. Biomes occur because of global weather patterns and topography. Temperature and rainfall determine the different biomes

20. Desert Biome Mojave Desert Low elevation Mostly very hot soil temps (above 60⁰C /140⁰F) during the day Low precipitation (less than 30 cm per year) Cacti and shrubs with water storage tissues, thick cuticles, and other adaptations to reduce water loss

22. Grassland Biome Tropical Grasslands & Temperate Grasslands Savanna (Africa) & Prairies (North America) Cold temperatures in winter, hot in summer Seasonal drought is common, w/ occasional fires, medium amount of moisture Prairie grasses hold soil with long roots, occasional fire prevents trees and shrubs from invading grasslands

24. Shrubland Biome West Coast of USA, Cape Town, South Africa Mild temperatures in winter and long, hot summers Rainy winters and dry summers Dry woody shrubs are killed periodically by fires. Shrubs store food in fire resistant roots. They regrow quickly and produce see, which germinates only after a fire.

26. Temperate Deciduous Forest Eastern North America, Mid Europe Lower elevations Very hot in summer, very cold in winters High rainfall spread evenly over the year. In winter water may freeze for short times Deciduous trees like oak, hickory, and maple dominate forest. Warmer seasons see a wide variety of herbaceous plants grow and flower on forest floor

28. Tropical Rainforest Central & South America (Amazon river), Parts of Africa, Southeast Asia Low elevations Very warm temperatures Very high precipitation (more than 250 cm per year) High plant diversity. Canopy of trees, layer of shrubs, ground layer of herbaceous plants and ferns. Large trees have vines, trees have orchids and bromeliads tucked into branches

30. Tundra Arctic Tundra (Alaska, Northern Canada, Northern Russia) High elevations Very cold, in summer upper layer of soil thaws, but lower layers remain frozen, known as permafrost Little precipiation Low growing plants (lichen and mosses), few grasses and shrubs. Permafrost prevents roots from growing deeply. Continuous daylight in summer allows plant growth and reproduction

32. Coniferous Forest (Taiga) North America, Eurasia High elevations Slightly warmer than tundra Small amounts of precipitation, but wet due to lack of evaporation Cone-bearing trees such as pine, spruce, fir, and hemlock.