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Semester 2 Final Review Part 2

Semester 2 Final Review Part 2. Carbohydrates, Photosynthesis & Respiration and Ecology. Cycles. Water Carbon Nitrogen. Energy transfer through an ecosystem is ONE WAY Most energy is lost as heat

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Semester 2 Final Review Part 2

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  1. Semester 2 Final Review Part 2 Carbohydrates, Photosynthesis & Respiration and Ecology

  2. Cycles Water Carbon Nitrogen

  3. Energy transfer through an ecosystem is ONE WAY • Most energy is lost as heat • Nutrients such as nitrogen, water and carbon are able to cycle through an ecosystem and be reused. Nutrient Cycles

  4. Condensation: The changing of water from a vapor to a liquid Transpiration: Release of water through the leaves of plants into the atmosphere • Precipitation: • Any form of water • falling from the sky • such as rain, sleet, • snow, and hail Evaporation: Liquid water rising converting to water vapor and rising to the atmosphere.

  5. THE CARBON CYCLE

  6. Link between Atmosphere and Terrestrial: Plants acquire CO2 thru stomata in their leaves and incorporate it in to organic molecules of their own biomass  photosynthesis

  7. Link between Atmosphere and Terrestrial:  Some of this organic material becomes a carbon source for consumers  Carbon is cycled quickly because of high demand from plants

  8. Link between Atmosphere and Terrestrial: • Allorganisms return CO2to the atmosphere thru respiration • Decomposition recycles carbon to the soil and back to atmosphere • Fires oxidize organic material to CO2 (burning) Link to animation

  9. Carbon is accumulated in wood and other durable organic material Organic detritus, under intense pressure, changes into coal and petroleum in rock. Carbon is also stored on land:

  10. The Nitrogen Cycle • Nitrogen gas (N2) makes up 79% of our atmosphere • Nitrogen is needed by plants and animals to make proteins and DNA • It ranks fourth behind oxygen, carbon, and hydrogen as the most common chemical element in living tissues. • Most organisms CAN NOT obtain nitrogen through the atmosphere!

  11. The Nitrogen Cycle • Since animals cannot get nitrogen directly from the atmosphere they must eat it through plants. • Certain plants can pull atmospheric nitrogen into their roots and make NO3 • Legumes, Red Alder trees Rhizomes

  12. The Nitrogen Cycle • Animals then eat the plants that contain NO3 and incorporate it into their body • DNA • Proteins

  13. Cycles Vocabulary Evaporation Fossil Fuels Condensation Nitrate Precipitation Nitrogen Fixing Transpiration Denitrification Stomata Carbon Source Carbon Sink Decomposition Combustion

  14. Climate Change

  15. Greenhouse Effect Light energy from the sun (solar radiation) is either reflected or absorbed by the Earth. When it is absorbed it is converted into heat energy (infrared radiation). That heat energy either escapes the Earth through the atmosphere, or gets absorbed by greenhouse gases and reflected back down. This is how heat is trapped within the troposphere and how the Earth stays warm.

  16. Greenhouse Effect Greenhouse gasses include: Water (H2O) Methane (CH4) Carbon Dioxide (CO2) Nitrous Oxide (N2O) The first 3 are very natural, and in fact necessary to keep the Earth warm.

  17. Global Warming The greenhouse effect is natural and necessary for most life here on Earth. Without the greenhouses gases in our atmosphere the Earth’s average temperature would be -160C ! This happened to Mars which lost its atmosphere. If a planet has extremely high concentrations of greenhouse gases in its atmosphere however it can have a runaway greenhouse effect. This is the case with Venus, whose high concentrations of carbon dioxide give it an average surface temperature of 4250C!!!

  18. Effects of Climate Change High global temperatures (Heat Waves) Increased drought, extreme weather. Raising sea levels caused by melting ice. Acidification of the ocean.

  19. Positive Feedback We call this a positive feedback loop where: A produces more of B, which then in turn produces more of A. Melting sea ice creates a lower albedo, which then in turn causes more ice to melt.

  20. Negative Feedback Of course there is also negative feedback as well. You are probably most familiar with this in homeostasis. With negative feedback: A produces B, which then stops or lowers the production of A

  21. Negative Feedback With climate change there are many more examples of positive rather than negative feedback. Here is one example of negative feedback in the climate: Global warming is expected to intensify rates of land degradation and desertification, which in turn results in more windblown dust. Dust acts to cool the surface (by raising albedo), thus lowering the temperature of the Earth.

  22. Positive vs. Negative Feedback . Positive feedback tends to promote instability in systems (think spiraling out of control). Negative feedback tends to promote stability in systems (think again about homeostasis).

  23. Climate Change Vocabulary Positive Feedback Negative Feedback Greenhouse Effect Greenhouse Gases Climate Change

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