diff --git a/Grade 9/Science/SNC1DZ/Study_Sheet.md b/Grade 9/Science/SNC1DZ/Study_Sheet.md index 7494d9c..bec8725 100644 --- a/Grade 9/Science/SNC1DZ/Study_Sheet.md +++ b/Grade 9/Science/SNC1DZ/Study_Sheet.md @@ -426,6 +426,13 @@ atmosphere, river to lake) - **Reshaping the geological features of Earth** - Erosion and sedimentation +### Human Inpacts +- Humans building dams (flooding is a problem!) +- Deforestation contributes to global warming, hence melting glaciers and causing flooding in cities +- (Also less transpiration from clear cutting) – pg. 48 +- Factories and cars pollute the air, leading to acid precipitation +- Oil spills destroy aquatic ecosystems + ## Carbon Cycle - Fourth most abundant element in universe - Building block of all living things @@ -436,8 +443,23 @@ atmosphere, river to lake) - CO2 is a waste product of cellular respiration - Plants use carbon dioxide and water to form simple sugars (photosynthesis) - Light Energy --> Chemical Energy +- Carbon dioxide is `returned to the enviornment by: + 1. `Resipiration` in plants, animals & micro-organisms. + 2. `Decay` caused by micro-organisms (decompoers). + 3. `Combustion` i.e. Burning fossil fuels. +- **Phtosynthesis** + - CO2 is converted to glucose using water and sunlight +- **Cellular Respiration** + - Breaks down glucose to release energy, expel CO2 +- **Oceans are a HUGE carbon sink**. - +### Human Impacts +- **Mining & burning fossil fuels**: Speed up release of CO2 to the atmosphere. +- **Deforestation & clearing vegetation**: ↑ CO2 in atmosphere. +- **Acid rain**: release CO2 from limestone. +- CO2 in the atmosphere is now higher than it has been in at least **800 000 years**. + ## Nitrogen Cycle - The most abudant gas in the atmopshere (~78%) - `Nitrogen Fixation`: The process that causes the strong two-atom nitrogen molecules found in the atmopshere to break apart so they can combine with other atoms. @@ -446,8 +468,10 @@ atmosphere, river to lake) - Atmopspheric nitrogen = N2 - Most living organisms are `unable` to use this form of nitrogen - Therefore, must be **converted** to a usable form! + + ### STEPS/PROCESSES -- +- ### Nitrogen Fixation - Most of the nitrogen used by living things is taken from the atmosphere by certain bacteria in a process called `nitrogen fixation`. @@ -456,6 +480,8 @@ atmosphere, river to lake) - Humans add nitrogen to soil through fertilizer - 3 ways nitrogen to get fixed 1. Atmopheric Fixation + - Lightning Storms + - stroms and fuel burning in car engines produce nitrates, which are washed by rain into soil water. 2. Industrial Fixation 3. Biological Fixation - 2 types @@ -464,7 +490,14 @@ atmosphere, river to lake) - Nitrogen changes into ammonium. 2. Symbiotic Relationship Bacteria - Bacteria live in the roots of legume family plants and provide the plants with ammonium(NH4+) in exchange for the plant's carbon and a protected biome. - +- `Nitrites` are absorbed by plant roots and converted to plant protein. +- `Nitrates` **can be absorbed by other plants** to continue the cycle. +- `Denitrifying bacteria` convert soil nitrates into N2 gas + - This is a `loss` of N2 from the cycle + +### Human Impacts +- Nitrates also `enters` the cycle **through the addition of nitrogen rich fertilizers to the soil** – made industrially from nitrogen gas (Eutrophication – pg. 60) +- Factories release NO compounds (acid rain) ## Nutrient Recycling - There is a `limited` amount of `nutrients` on earth @@ -473,7 +506,14 @@ atmosphere, river to lake) - There are similar cycles for all nutrients. - When plants and animals die, their nutrient content is `not wasted`. - Bacteria and fungi decompose the remains and release the nutrients back into the abiotic environment (i.e. into the soil, nearby water and air). +- Nutrients are then taken up by other plants and used to make new organic material. +- This material is passed on down the food chains and is reused by all the chain members. +- When death occurs for these members, the nutrients are again returned to the abiotic environment and the cycling of nutrients continues in this circular way. +- This ensures that there is no real longterm drain on the Earth’s nutrients, despite millions of years of plant and animal activity. +### Summary Of Nutrient Recycling +- The way in which elements are continuously being broken down and/or exchanged for reuse +- Occurs between the living and non-living components of an ecosystem. ## Benefits of Succession - Provides a mechanism by which ecosysmtems maintain their long term sustainability.