• Microorganism chart handout (on your own )• Carbon and Nitrogen cycles– Notes

• Symbiotic Relationships (12a)– Practice, notes

**8 CLASSES, INCLUDING TODAY, BEFORE YOU TAKE THE BIOLOGY STAAR TEST

Tuesday PAP Biology

Carbon and Nitrogen CyclesBiology 12(E)

Learning Objectives• Describe the flow of matter through the

carbon and nitrogen cycles• Explain the consequences of disrupting the

carbon and nitrogen cycles

Carbon and Nitrogen Cycles

Nitrogen – essential element for life• Nitrogen gas (N2) – 78% of atmosphere, not usable by most

organisms• Within living organisms (biomolecules)– Proteins

Nitrogen cycle – means by which nitrogen gas converted to usable form then cycled through ecosystem

Nitrogen Cycle

Nitrogen Cycle

Processes that contribute to nitrogen cycle:• Ammonification

– when plants and animals excrete wastes or die, decomposers convert their nitrogen compounds to ammonia (NH4)

• Nitrification – nitrifying bacteria

in soil convert ammonia to nitrites (NO2

–)

Nitrogen Cycle

Processes contributing to nitrogen cycle:• Nitrogen fixation – bacteria found in roots of legumes (beans and peas)

N2 Nitrates (NO3–)

– Plants use nitrates to synthesize proteins, stored in plant tissues

– Animals eat plants, acquire usable nitrogen

– Nitrogen passed through food chain

Nitrogen Cycle

Processes that contribute to nitrogen cycle:• Nitrates assimilated by plants into tissues• Eaten by animals• Denitrification –

bacteria convert compounds into nitrogen gas

Nitrogen Cycle

Disruptions to nitrogen cycle:• Burning of fossil fuels (fire!) – releases excess nitrogen into

atmosphere

Consequence:• Greenhouse effect• Acid rain – emissions form nitric

acid in atmosphere– Affects soil and water quality– Can kill plants

Disruptions to Nitrogen Cycle

Disruptions to nitrogen cycle:• Excessive irrigation and

erosion – washes away nitrogen

Consequence: • Plant growth fails

Disruptions to Nitrogen Cycle

Disruptions to nitrogen cycle:• Fertilizing crops – excess nitrogen enters soil and water

Consequences:• Adverse effect on marine life

– Algal blooms – causes oxygen deficiency in aquaticecosystems

Disruptions to Nitrogen Cycle

Disruptions to nitrogen cycle:• Ranching – livestock waste

releases ammonia into soil and water supplies

Consequences:• Poor water quality – health risk• Poor plant growth

Disruptions to Nitrogen Cycle

Carbon – key element in organic matter• In the environment

– Carbon dioxide (CO2) gas in

atmosphere and sea water– Long carbon chains in fuels

• Inside living organisms – all of our biomolecules

Carbon cycle – means by which carbon is cycled between the environment and living tissues

Carbon Cycle

Processes contributing to carbon cycle:• How C Leaves the environment– Photosynthesis – transform CO2 into glucose

(C6H12O6)• Stored in cells and tissues of plants• Passed through food chain as one organism eats

another

• How C is Returned to the environment from organisms– Cellular respiration – organisms break down complex

compounds and release CO2

– Decomposition – microorganisms and some fungi break down dead organisms and release CO2

Carbon Cycle

Carbon Cycle

Disruption to carbon cycle:• Burning fossil fuels• Deforestation• Additional humans

and animals

Consequence:• Increases greenhouse effect

Disruptions to Carbon Cycle

Greenhouse effect – the trapping of heat by greenhouse gasses such as carbon dioxide• Increase in gasses increases amount of heat trapped

Impacts of increasing greenhouse effect on all ecosystems• Raises temperature• Changes atmospheric moisture patterns• Melts polar ice caps, raising water levels

Greenhouse Effect

Disruption to carbon cycle:• Deforestation – removal of forests

– Often by burning– Releases CO2 into atmosphere

Consequences:• Contributes to

greenhouse effect• Reduces ecosystem’s ability

to remove CO2 through photosynthesis

Disruptions to Carbon Cycle

Learning Objectives• Describe the flow of matter through the

carbon and nitrogen cycles• Explain the consequences of disrupting the

carbon and nitrogen cycles

Carbon and Nitrogen Cycles

• Describe the impact of the following on the environment with regards to BOTH the carbon and nitrogen cycles:– A forest fire– Burning coal in a factory– Automobile emissions

Essay using your notes and your own paper!!! Turn into box when finished…