Refined grade 9 IB science notes, used to pass the final exam with 96 percent. Includes a full summary of all the curriculum. Great for both Academic and pre-IB students.
Expected to get detailed course notes,but instead has a limited overview with no diagramss.Waste of time and money
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Unit 1 Test Review Sheet
Atmosphere
● Gasses that surround the earth
● Affects temperatures near the earth (keeps in heat)
● out solar radiation
● 78% nitrogen gas, 21% oxygen gas, less than 1% of argon, water.vapour, carbon
● dioxide and other gases
Lithosphere
● rocky outer shell of the earth
● made of rocks & minerals
● In mountains, ocean floors
● includes layers of soil
Hydrosphere
● all the water on, above and below the earth’s surface
● oceans (97% of hydrosphere), lakes, ice, groundwater and clouds, water vapour
Biosphere
● where life exists (within the other spheres)
● Biosphere -Biomes -Ecosystems
Organization of life
● Organisms- population- community- ecosystem -biosphere
Ecosystem
● All the living organisms in a region and interact with each other and their non-living
environment
● Ecosystems are described by their abiotic and biotic factors
Biotic Factors
● Living things, remains, and products
● Eg. competition for niche, resources, mates, disease, biodiversity, predation, etc.
Abiotic Factors
● Non living components – physical and chemical
● Eg. sunlight, temperature, wind, moisture and soil conditions
Food chains and Food webs
● 10% rule- Only 10% gets passed onto the other organisms (the other 90% is lost through
heat or metabolic process)
, ● Trophic levels- 1st trophic level is an autotroph or a producer. 2nd trophic level are
primary consumers or herbivores. 3rd trophic level is a carnivore or a secondary
consumer. 4rth trophic level is a carnivore or a tertiary consumer.
● Food webs are a series of interconnected food chains
Biogeochemical Cycles
● Conservation of mass- matter cannot be created or transformed
● Matter is reused, recycled, rearranging
● Matter moves through abiotic and biotic environment (water cycle, hydrologic cycle)
● Steps/Processes within C and N cycles - Abiotic to Biotic factors ( sunlight is given to
plants to form glucose) and Biotic to Abiotic factors ( Nutrients return to abiotic pools
(e.g. Air/water)
Water Cycle
● Ways that water is returned to the atmosphere : evaporation and transpiration
● Water makes its way into lakes, rivers, and seas by: surface runoff
● Water is removed from the atmosphere through condensation and precipitation
Carbon Cycle
● All living matter has carbon in it
● Organic substances: substances containing both C and Hydrogen (H), and often Oxygen
(O) and N
● Distribution of carbon in biotic factors - fats, proteins, glucose and decaying organic
matter and waste - humus, peat
● Distribution of carbon in abiotic factors - co2 in atmosphere and oceans, carbon in the
earth's crust
The Backbone of Carbon Cycle
● Photosynthesis- co2 is converted to glucose by the sunlight and water
● Cellular respiration - breaks down glucose to release energy
Ways that carbon is returned and r emoved into the atmosphere
● Respiration from animals - breathe in oxygen release carbon dioxide
● Burning fossil fuels- turn carbon based molecules into CO2 and H2O
● Decomposition- release carbon dioxide into atmosphere when they break elements
● down
● Photosynthesis removes carbon because it removes carbon to turn it into glucose
Human impacts on carbon cycle
● Construction
● Deforestation
● Driving
● Acid rain - releases CO2 from limestone
, Carbon Sinks
● Carbon sinks can be natural or man-made. They absorb more carbon than they release
whereas carbon source is anything that releases more carbon than they absorb.
● Peat bogs- have slow decomposition results in slow release of C to air
● Oceans - dissolved CO2 for Photosynthesis- Incorporated in shells of marine organisms
● Earth’s crust- Mining and burning fossil fuels release carbon as CO2
Distribution of Nitrogen
● Biotic- living organisms (Proteins, DNA) and decaying organic matter and wastes
● Abiotic - Atm – 78% N2 gas#, Nitrates (NO3-)**, Ammonia (NH3),Nitrites (NO2-)
Organisms consume more N than they use
Extra N is excreted in the form of urea or ammonia in their wastes
When organisms die, N in their bodies is recycled by decomposers (eg. micro-organisms).
Human influences on N cycle
● Fertilizers have N compounds to help plants grow (Industrialized N-fixation) Fertilizers
are carried by runoff → water → eutrophication
● Burning of fossil fuels Release nitrogen oxides (NOx) to atm
● Crop rotations - Farmers rotate between regular crops and leguminous plants to ↑ N soil
content
Limiting Factors and Carrying capacity
● Biotic and abiotic factors- not enough sunlight, competition, not enough food, not enough
space, weather, shelter
● Carrying capacity is the number of species an ecosystem can support
● Density-Independent Limiting Factors- Are generally ABIOTIC
● Density-Dependent Factors-Are generally BIOTIC
What is Biodiversity?
● Variety of life that exists in a specific ecosystem or biome
● Higher the number of species in an area, the higher the biodiversity of that region
● Warmer climate- higher biodiversity
Benefits of Biodiversity
● Cultural services- recreation, aesthetic, spiritual experiences
● Ecosystem Products- food sources, plant dyes, rubber, aspirin, wax
● Environmental Benefits- maintain abiotic and biotic features, cycles of nutrients, protect
soil from wind and water erosion
Human actions threaten biodiversity
● Increase rate of extinct species
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