Ecosystems: Basics

1. Ecosystems: Basics • Definition • Structure • Components • Needs

2. Definition • An Ecosystem is: • All the communities that live in an area as well as the abiotic factors of water, soil and climate

3. Structure • Highly organized and well structured environment in which all parts exist in balance

4. Components of the Ecosystem • Habitat: type of environment in which a species lives • Species: group of similar organisms that can breed and reproduce • Population: members of a species that live in the same area • Community: all the populations that live and interact in the same environment • Biodiversity: variety of species

6. Levels of Organization

7. Needs of Organisms so they will survive in the Ecosystem: • Water, energy, living space, suitable climate • So, remember the difference between biotic and abiotic??

8. Ok, let’s talk about how organisms needs will be met. 1. Water – 2. suitable climate 3. Living Space 4. Energy – this one we need a little more discussion on…..hence, we will learn a bit about soil and nutrient cycling as organisms need nutrients and energy

9. How do organisms get energy?? • Producer is…. And gets energy from the …… • Consumer is …. And gets energy from…. • Herbivore • Carnivore • Omnivore • Scavengers Decomposers are …. And gets energy from

10. How are nutrients and Energy Related? Humans and other consumers need nutrients from plants to get energy (read connect)

11. Important Nutrients that are found in soil • Nitrogen • Color and size • Phosphorous • New seedlings, formation of roots and development of seeds and fruits, transfer of energy • Potassium • Plant metabolism, resistance to disease, synthesis of starch

12. Why those nutrients are important for humans: Oxygen (65%) and hydrogen (10%) are predominantly found in water, which makes up about 60 percent of the body by weight. It's practically impossible to imagine life without water.Carbon (18%) is synonymous with life. Its central role is due to the fact that it has four bonding sites that allow for the building of long, complex chains of molecules. Moreover, carbon bonds can be formed and broken with a modest amount of energy, allowing for the dynamic organic chemistry that goes on in our cells. Nitrogen (3%) is found in many organic molecules, including the amino acids that make up proteins, and the nucleic acids that make up DNA.Phosphorus (1%) is found predominantly in bone but also in the molecule ATP, which provides energy in cells for driving chemical reactions. Potassium (0.25%) is an important electrolyte (meaning it carries a charge in solution). It helps regulate the heartbeat and is vital for electrical signaling in nerves.

13. Carbon Cycle

14. Nitrogen Cycle

16. Movement through the atmosphere is generally rapid -- Movement through the soils is generally slow -- Movement from terrestrial biosphere to the ocean (via stream flow, usually) must be replaced by movement either through the atmosphere (such as with nitrogen and carbon) or by weathering (such as with phosphorous or calcium). The atmospheric route is much faster! Increased transport by stream flow severely disrupts the cycles of elements without a gaseous phase. (http://www.colorado.edu/GeolSci/courses/GEOL1070/chap04/chapter4.html)

17. Soil Formation, Nutrients and cycling, and erosion

18. Soil is • A mixture of mineral particles, air, water, bedrock, and living and decaying organisms. • “stuff of life” or our “ultimate resource” – heavy dependence on plants in our food chains!

19. General A. Soil Size 1. Sand 2. Silt 3. Clay

20. Soil Properties • Porosity – measure of volume of space that lies between soil particles • Permeability – rate at which fluids move through soils • Water Retention – amount of water soil can absorb

21. Soil Formation • Weathering • Mosses and Lichens --Young soils rocky, ability to support plant life limited • Mature soils take longer time = organic materials – support growth of many plants • Hundreds of thousands of years may be required to create 10 cm of soil

22. Five Key factors • Parent material • Time • Climate • Biotic processes • topography

23. Parent Material --Areas of Soil • Bedrock – igneous, metamorphic, sedimentary • Source of inorganic material of soil • Nutrient richness depends in part on nutrients stored in bedrock – phosphorus, potassium, calcium, iron, and manganese • Parent rock – area of bedrock that is source of area of soil

24. Areas of Soil cont. • Soil profile – vertical cross section of soil from surface to bedrock • Horizons – O, A, E, B, C, • C – weathered bedrock • B – soil receiving materials washed down from overlying horizons • E – pale soil layer mostly sand and silt between A and B horizons • A – Dark brown, made mostly of decomposing organic matter (commonly known as top soil) • O – Dead plant and animal matter (part of top soil)

25. Time • Can take hundreds of thousands of years to make soil

26. Climate and Soil • Precipitation • Weathering of bedrock • High could mean more nutrients being washed out • Temperature • Warm wet conditions cause rock to decay faster • Climate influences nutrient cycling

27. Nitrogen cycle

28. Soil pH – power of Hydrogen A. Measures soil acidity or the hydrogen ion concentration in soil solution B. pH scale 0-14 0 acid 7 base 14 C. Raise pH Lime Lower pH Sulfur D. Optimal pH 6-7

29. VIII. Desirable Plant pH Scale A. Strongly Acidic Soils (5.0-5.5) 1. Potatoes 2. Watermelon B. Moderately Acidic Soils (5.5-6.5) 1. Wheat 4. Peanuts 7.Strawberry 2. Soybeans 5. Cotton 3. Corn 6. Oats C. Slightly Acidic Soils (6.5-7.0) 1. Alfalfa 2. Sweet Clover

30. Biotic Processes • Includes • organic contents • Interactions between soil by organisms, especially decomposers • Decomposers are bacteria or fungi that eat dead organisms, in doing so break them down and release nutrients into soil! • Other burrowing animals allow for water and air to move through the soil

31. II. Cation Exchange Capacity (CEC) A. CEC = measure of a soils nutrient holding capacity. - Cation: + charged ions (attracted to surface of clay – potassium, calcium, ammonium, magnesium) - Anion: - charged ions (not attracted to clays – nitrate – more readily washed out of a clay soil B. CEC depends on amounts of clay and organic matter in soil

32. Topography • Slope and shape of land

33. Reasons for Soil loss • Deforestation • Erosion • Soil Mismanagement

34. Deforestation • Rapa Nui as an example • Land is cleared for many reasons • Mining, construction, agriculture,

35. Deforestation in Madagascar – Reason: cultivation of coffee beans

36. Erosion: Other Info A. Two types of erosion 1. Wind 2. Water a. Three types of water erosion 1. Rill – channels across field 2. Sheet – raindrops remove particles 3. Gully – rills formed together

37. Erosion • Loss of topsoil by wind or other forces • Four categories • very severe erosion- 75% or more and large gullies are present • severe erosion - 75% of soil has eroded but no large gullies present • moderate erosion- 25 to 75% of soil has eroded with small gullies present • none to slight erosion - less than 25% of soil has eroded and no gullies are present

38. Soil mismanagement • Overgrazing • Using Pesticides or fertilizer • Irrigation • All leads to “desertification” – most widely noticed near a desert but happening in a wide variety of places!.

39. Land Improvement • Four common practices to improve arable land • Irrigation • Erosion Control • Drainage • Forming (land forming)- surface is smoothed or reshaped.

40. Soil Conservation and Land Management/ Sustainable Agriculture • Strip Cropping • Contour Farming • Terracing • Shelter Belt • Crop rotation • Using less destructive chemicals on crops • Integrated Pest Management

41. Terracing and shelter belts

42. VI. Effects of Liming on Plant Growth A. Correct soil acidity B. Improves effectiveness and efficiency of fertilizers C. Reduces solubility of toxic elements D. Supplies calcium and magnesium E. Improves biological activity F. Improves physical conditions of soil G. Improves yield