Chemical/Nutrient Recycling in Ecosystems

1. Chemical/Nutrient Recycling in Ecosystems 1

2. In addition to energy, what do organisms need to survive?

3. Anything that has mass and takes up space Matter is recycled in ecosystems What is matter composed of? Matter

4. Elements Matter is composed of elements Elements, made of atoms, are the basic unit of matter

5. Levels of organization in the biosphere Particles of matter atoms  elements molecules  macromolecules organelles  cells tissues organs organ systems organisms populations  communities ecosystems biomes  biosphere

6. Elements in Living Things The elements found in significant amounts in organisms are Carbon Hydrogen Oxygen Nitrogen “HONC” HONC if you love science! Also phosphorus and sulfur “CHONPS”

7. Law of Conservation of Mass Matter is neither created nor destroyed! So what happens when matter seems to just “appear” or “disappear”?

8. What happens to matter in the biosphere? Matter is recycled by naturally occurring chemical reactions or phase changes (changes in state)

9. What four elements primarily make up living organisms? These elements (along with others such as ________ and ________ are the basis of life’s most important compounds:

10. What four elements primarily make up living organisms? Hydrogen, Oxygen, Nitrogen, Carbon These elements (along with others such as _sulfur__ and _phosphorus_ are the basis of life’s most important compounds: water, carbohydrates, lipids, nucleic acids and proteins

11. CYCLES OF MATTER In other words, a handful of elements combine to form the building blocks of all known organisms. However, organisms cannot manufacture these elements and do not “use them up” . You may wonder where these essential elements come from and how their availability affects ecosystems.

12. Although energy in the form of sunlight is constantly entering the biosphere, Earth doesn’t receive a significant, steady supply of new matter from space. Unlike the _____flow of _____, _____ is _____within and between ecosystems

13. CYCLES OF MATTER Although energy in the form of sunlight is constantly entering the biosphere, Earth doesn’t receive a significant, steady supply of new matter from space. Unlike the one-way flow of energy, matter is recycled within and between ecosystems

14. BIOGEOCHEMICAL CYCLE • Process in which elements, chemical compounds, and other forms of matter are passed from one organism to another and from one part of the biosphere to another. • As matter moves through these cycles, it is transformed which means that it is never created or destroyed, just changed.

15. The Water CycleThe pathway of water in an ecosystem 15

16. The Water Cycle

17. The Carbon and Oxygen CyclesThe pathway of carbon and oxygen through an ecosystem

18. The Carbon and Oxygen Cycles Almost all oxygen in Earth’s atmosphere originally came from the metabolic activities of plants How do C and O cycle through the biosphere? 2 processes – PHOTOSYNTHESIS AND CELLULAR RESPIRATION

19. The Carbon and Oxygen Cycles

20. How have humans affected the carbon cycle? • What processes are putting too much carbon dioxide into the atmosphere? • What problem does this lead to?

21. The Nitrogen CycleThe pathway of nitrogen through an ecosystem 21

22. Nitrogen is an important element in living things Used to make proteins and nucleic acids! Nitrogen gas (N2) makes up 78% of the earth’s atmosphere However…most organisms cannot use N2 directly Why can’t organisms use N2 directly?

23. How do plants get nitrogen? • Rely on Nitrogen Fixing Bacteria! • These bacteria live in the roots of some plants (legumes – peas, peanuts, beans) and in the soil • These nitrogen fixing bacteria are the only organisms that can “fix” atmospheric nitrogen into a usable form (ammonia)

24. Plants and Nitrogen Compounds So, nitrogen is obtained by plants either directly from the bacteria in their roots, or in the soil Some nitrogen in the soil also comes from decaying matter – decomposers break down waste and dead organisms into usable forms of nitrogen

25. What are the usable forms of nitrogen? • Most plants usenitrogen in two inorganic forms to make proteins • NH3 (ammonia) and NO3- (nitrate) • Some also use nitrites

26. Animals must eat plants to meet their nitrogen needs So, what organisms are absolutely necessary for the nitrogen cycle to continue? BACTERIA!!

27. How does nitrogen get back into the atmosphere? More bacteria! Other bacteria convert nitrates back into nitrogen gas. This process is called DENITRIFICATION.

28. Atmospheric nitrogen fixation – a relatively small amount of nitrogen gas is converted into usable forms by lightning

29. The Nitrogen Cycle

30. Do Now 12/6 What organisms “drive” the nitrogen cycle? What would happen to producers if nitrogen fixing bacteria were removed from an ecosystem? What would happen to consumers? What important role do plants play in the carbon cycle?

31. The Phosphorus Cycle • Movement of phosphorus from environment to organisms and back to environment • P is needed to form bones and teeth in animals • P is needed to form nucleic acids

32. How do plants and animals get phosphorus? • Plants get it from soil and water • Animals get it by eating plants or other animals that have eaten plants • Slow cycle, does not usually involve atmosphere

33. How does P enter soil? • When rocks erode, a little P dissolves as phosphates in soil and water • P added to soil and water when excess p is excreted in waste from organisms and when organisms die and decompose

34. How do plants and animals get phosphorus? • Plants absorb phosphates in the soil through their roots • Animals eat plants • Some p washes off land and ends up in oceans • Many phosphate salts not soluble in water, so they sink to bottom of ocean and accumulate as sediment

35. How do humans affect phosphorus and nitrogen cycles? • Fertilizer use! • Read in your text about fertilizers and the nitrogen and phosphorus cycles! • Also read about acid rain!

36. The End 36