Biology. Slide 1 of 33. End Show. Copyright Pearson Prentice Hall

Transcription

1 Biology 1 of 33

2 2 of 33

3 Recycling in the Biosphere Recycling in the Biosphere Energy and matter move through the biosphere very differently. Unlike the one-way flow of energy, matter is recycled within and between ecosystems. Biogeochemical Cycles 3 of 33

4 The Water Cycle The Water Cycle All living things require water to survive. 4 of 33

5 The Water Cycle Water moves between the ocean, atmosphere, and land. 5 of 33

6 Nutrient Cycles How are nutrients important in living systems? 6 of 33

7 Nutrient Cycles Nutrient Cycles All the chemical substances that an organism needs to sustain life are its nutrients. Every living organism needs nutrients to build tissues and carry out essential life functions. Similar to water, nutrients are passed between organisms and the environment through biogeochemical cycles. 7 of 33

8 Nutrient Cycles The Carbon Cycle Carbon is a key ingredient of living tissue. Biological processes, such as photosynthesis, respiration, and decomposition, take up and release carbon and oxygen. Geochemical processes, such as erosion and volcanic activity, release carbon dioxide to the atmosphere and oceans. 8 of 33

9 Nutrient Cycles CO 2 in Atmosphere Photosynthesis Volcanic activity feeding Respiration Decomposition Deposition Human activity CO2 in Ocean Photosynthesis Erosion Respiration Uplift feeding Fossil fuel Carbonate Rocks Deposition 9 of 33

10 Demonstration of the carbon cycle Class work: make a poster of the carbon cycle in your group. Draw all seven pathways and choose one route to follow 10 of 33

11 Nutrient Cycles The Nitrogen Cycle All organisms require nitrogen to make proteins. Although nitrogen gas is the most abundant form of nitrogen on Earth, only certain types of bacteria can use this form directly. Such bacteria live in the soil and on the roots of plants called legumes. They convert nitrogen gas into ammonia in a process known as nitrogen fixation. 11 of 33

12 Nutrient Cycles N 2 in Atmosphere Synthetic fertilizer manufacturer Decomposition Atmospheric nitrogen fixation Uptake by producers Reuse by consumers Uptake by producers Reuse by consumers Bacterial nitrogen fixation Decomposition excretion NH 3 NO 3 and NO 2 Decomposition excretion 12 of 33

13 Nutrient Cycles Other soil bacteria convert nitrates into nitrogen gas in a process called denitrification. This process releases nitrogen into the atmosphere once again. 13 of 33

14 Nutrient Cycles The Phosphorus Cycle Phosphorus is essential to organisms because it helps forms important molecules like DNA and RNA. Most phosphorus exists in the form of inorganic phosphate. Inorganic phosphate is released into the soil and water as sediments wear down. 14 of 33

15 Nutrient Cycles Organic phosphate moves through the food web and to the rest of the ecosystem. Organisms Land Ocean Sediments 15 of 33

16 Nutrient Limitation Nutrient Limitation The primary productivity of an ecosystem is the rate at which organic matter is created by producers. One factor that controls the primary productivity of an ecosystem is the amount of available nutrients. 16 of 33

17 Nutrient Limitation If a nutrient is in short supply, it will limit an organism's growth. When an ecosystem is limited by a single nutrient that is scarce or cycles very slowly, this substance is called a limiting nutrient. 17 of 33

18 Nutrient Limitation When an aquatic ecosystem receives a large input of a limiting nutrient such as runoff from heavily fertilized fields the result is often an immediate increase in the amount of algae and other producers. This result is called an algal bloom. Algal blooms can disrupt the equilibrium of an ecosystem. 18 of 33

19 3 3 Continue to: - or - Click to Launch: 19 of 33

20 3 3 Transpiration is part of the a. water cycle. b. carbon cycle. c. nitrogen cycle. d. phosphorus cycle. 20 of 33

21 3 3 Carbon is found in the atmosphere in the form of a. carbohydrates. b. carbon dioxide. c. calcium carbonate. d. ammonia. 21 of 33

22 3 3 Biologists describe nutrients as moving through cycles because the substances a. start as simple organic forms that plants need. b. provide building blocks and energy that organisms need. c. are passed between organisms and the environment and then back to organisms. d. are needed by organisms to carry out life processes. 22 of 33

23 3 3 The only organisms that can convert nitrogen in the atmosphere into a form useful to living things are nitrogen-fixing a. plants. b. bacteria. c. detritivores. d. animals. 23 of 33

24 3 3 When an aquatic ecosystem receives a large input of a limiting nutrient, the result is a. runoff. b. algal death. c. algal bloom. d. less primary productivity. 24 of 33

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