Chapter 15 and 16
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The document summarizes several biogeochemical cycles including the water, carbon, oxygen, and nitrogen cycles. It also discusses ecological succession, population growth, human impacts on ecosystems such as algal blooms, biological magnification, and global warming. Key elements like carbon, oxygen, hydrogen, and nitrogen are recycled through these natural processes.
Chapter 15 and 16
- 1. Chapter 15 and 16 Part 2 W.R. McCammon Pisgah High School
- 2. Introduction There are four elements are found in all living organisms. Carbon Hydrogen Oxygen Nitrogen
- 3. Introduction These elements are recycled in the biosphere in biogeochemical cycles Bio – life Geo – land Chemical - chemicals
- 4. Introduction The first law of thermodynamics states that matter is neither created or destroyed it only changes form. Those 4 elements must be recycled or we’d run out of them. Energy is a one-way flow through the ecosystem.
- 5. The Water Cycle Evaporation – when liquid water changes to water vapor (gas) Condensation – Forms clouds – when water vapor (gas) turns back into liquid water. Precipitation – when liquid water falls to the ground as either rain, sleet, snow, or hail.
- 6. The Water Cycle Transpiration Plants take in more water than they will use for photosynthesis Some water exits the plant through stomata (leaf pores) in the leaves. The evaporation of water THROUGH the plant is called transpiration
- 7. The Water Cycle Complete page 242 in the green book If you don’t have a book, you must write all the questions. 1-8 and 1-6 Don’t forget your header that includes section number (15.3) and page number.
- 8. The Carbon Cycle Carbon is the building blocks of all the organic molecules like carbohydrates, lipids, and proteins. Carbon in the atmosphere is mostly CO 2 Animals produce carbon dioxide as a by-product of cellular respiration. Plants use that carbon dioxide to make their own food so carbon is recycled.
- 9. The Carbon Cycle When organisms die, the carbon in their bodes are returned to the soil and even may make fossil fuels like oil and gas. Combustion often produces carbon. Complete page 244 – practice 2; 1-5 Don’t forget the header.
- 10. The Oxygen Cycle Similar to the carbon cycle Plants produce oxygen (O2) as a by-product of photosynthesis. Animals use the oxygen for cellular respiration. Some oxygen is stored in metal oxides. Ozone (O3) is harmful to breath, but is used to shield us from harmful ultraviolet rays.
- 12. The Oxygen Cycle Page 245; 1-5
- 13. The Nitrogen Cycle Nitrogen is used to make amino acids which make up the proteins of the body. Nitrogen is also an important part of DNA. The atmosphere is 78% nitrogen (N2), but it is unusable in this form Plants need nitrogen in the form of Nitrate (-NO3)
- 14. The Nitrogen Cycle Nitrogen fixation is when nitrogen gas (N2) is converted into nitrate (-NO3). This process is carried out by bacteria and by lightning. When animals die or they get rid of body wastes, it adds nitrogen to the environment.
- 15. The Nitrogen Cycle Since this is a cycle, nitrate has to be turned back into nitrogen gas. This process is called denitrification and is carried out by different bacteria. Page 247; 1-5 and 1-6
- 16. Population Growth A group of organisms of the same species make up a population. A group of populations make up a community. Communities, plus the living and non-living parts, make up ecosystems. Ecosystems make up the biomes.
- 17. Population Growth S – shaped curve – the population will grow slowly at first and then more quickly. After a while the growth rate slows and levels off. The leveling off of the growth rate is the carrying capacity. The largest number of organisms of a species that can be supported by the environment.
- 18. Population Growth Population is limited by Birth rates Death rates Number of organisms entering the population Number of organisms leaving the population The amount of available resources These are called “limiting factors.”
- 19. Population Growth Unrestricted population growth can result in a ‘J’ – shaped curve. If there are no natural limited factors If there are no natural predators In a ‘J’ – shaped curve, growth is unrestricted. Page 265; 1-7
- 20. Ecological Succession Ecological succession is a series of predictable changes in an ecosystem. There are two types of succession
- 21. Ecological Succession Primary succession Occurs on the surface where there is no soil. Volcanic eruption. First organisms to move into an area is called the pioneer species. Usually lichens are the pioneer species in primary succession. Lichens break up rock into smaller pieces that will become soil
- 22. Ecological succession Secondary succession Occurs where soil is still present, but the land has been disturbed by clear cutting or wild fires. In Mississippi it typically goes Grass wild flowers shrubs soft woods hardwoods.
- 23. Ecological Succession Each ecosystem will achieve a final, stable stage in its development called a climax community. In MS – this is usually oaks, maples, etc. In aquatic succession, the body of water fills with sediment until there isn’t any water left. Pg 267; 16.4 – 1-5 and 1-5.
- 24. Human Impact on Ecosystems For thousands of years humans had very little impact on the environment because they were mostly hunter/gathers. Technology has lead to humans having a much greater impact on the environment along with competition for food, shelter, water, and space with animals.
- 25. Human Impact on Ecosystems Algal blooms occur when the runoff from a field contains fertilizer and causes algae to grow out of control . As the algae die, they use up the oxygen in the water and the fish and plant in the water suffocate.
- 26. Human Impact on Ecosystems Biological magnification occurs when a poison isn’t excreted from the organisms, but instead is passed on to the next member of the food chain. This keeps passing on larger and larger amounts of poison to the top level consumers until they are finally harmed.
- 27. Human Impact on Ecosystems Natural resources are used to get energy Non-renewable resources like coal, oil, and natural gas, takes millions of years to replenish when used up. Renewable resources like fresh water and trees, can be replenished more quickly, but are not available in unlimited amounts.
- 28. Human Impact on Ecosystems If an object is biodegradable it can be decompsed by microorganisms and returned to the soil in a matter of days, weeks, or months. (food, cotton clothing) Other products – non-biodegradable – could take hundreds of years or longer to break down. (Plastics, metals, Styrofoam, etc).
- 29. Human Impact on Ecosystems When large developments are built many natural habitats are destroyed and biodiversity decreases. Native species are often considered weeds and destroyed Native insects are considered pests and killed Non native plant and animal species can take over. Biodiversity is the variety of life in an area.
- 30. Human Impact on Ecosystems About 20 km above the earth is a layer of ozone called the ozone layer. Ozone is made up of 3 oxygen atoms and protects the surface of the earth from harmful ultraviolet (UV) radiation. UV radiation can causes sunburn, damages eyes, causes cancer, damages plant tissue, and lowers resistance to disease.
- 31. Human Impact on Ecosystems 30 years ago scientists noticed holes in the ozone layer. Chlorofluorocarbons (CFCs) were used in aerosol cans, air conditioners, freezers, refrigerators, and making plastic foam products.
- 32. Human Impact on Ecosystems CFCs break ozone apart. The US and other countries are scaling back using CFCs, but the CFCs already released will remain for 200 to 300 years.
- 33. Human Impact on Ecosystems Global warming Some scientists believe global warming is part of a natural cycle of increasing and decreasing global temperatures. Other scientists believe that humans are causing global warming.
- 34. Human Impact on Ecosystems Because of the industrial revolution humans have been putting more and more carbon dioxide in the atmosphere from combustion. Burning releases carbon dioxide Trees take in carbon dioxide, but humans cut down more and more trees each year so they can’t keep up This disrupts the carbon cycle.
- 35. Human Impact on Ecosystems Carbon dioxide acts like a blanket, holding in heat. If heat can not radiate into space, it will build up. Venus is hotter than Mercury because of increased levels of carbon dioxide in the atmosphere.
- 36. Human Impact on Ecosystems Although global warming may only increase the global temperature by 1 or 2 degrees, this could be catastrophic for living things. Melting ice caps Rising ocean levels Flooding Droughts Living things usually have an optimum temperature