Ecosystems: What Are They and How Do They Work? What is the Earth? The Geosphere 9/28/2014. Maloney

Transcription

1 Ecosystems: What Are They and How Do They Work? Maloney What is the Earth? Aside from the simplistic nature of the planet (a ball of rock gravitationally held in place, 93 million miles away from a star) there are multiple layers, all of which have a key role in our development There are 4 major spheres of the planet Atmosphere, hydrosphere, geosphere, biosphere The Geosphere The geosphere is all the earthen material of the planet From your feet down The basics are the crust, then mantle, then the core of the planet The geosphere drives all the movement on the surface of the planet 1

2 Hydrosphere The hydrosphere is all the water on the planet in all of its three forms This includes water vapor in the atmosphere, liquid water on the surface and subsurface and ice Roughly ¾ of the planet is water so this is extremely important Atmosphere The atmosphere is made of multiple parts but we are really concerned with 2 of them: Troposphere and Stratosphere Troposphere extends up between 4 and 11 miles above the earth s surface depending on where you are on the planet Stratosphere is famous for containing the Ozone (O 3 ) layer. This layer filters out 95% of the UV radiation coming from the sun Biosphere The biosphere is the area on the planet where life can be found From the highest flying bird (Bar Headed Goose) ~20,000 ft. above sea level to the deepest living archaeabacteria in the earths crust A very thin layer overall, which is why it is essential to protect the resources found there 2

3 Why are we so lucky? There are three components occurring on the planet which allow us to sustain life, without these three components, the planet would be void of life 1. High quality energy from the sun not cycling back, thus warming the lower atmosphere through the greenhouse effect 2. Chemical cycling we do not gain new matter in volumes large enough to make a difference so we have to cycle what we have 3. Gravity pulling in the atmosphere providing a habitat for life Components of an Ecosystem First we have to define what an ecosystem is: All the biotic (living) and abiotic (nonliving) components of an area Remember the levels of organization Organism (individual of a species) Population (same species) Community (multiple different species) Ecosystem (abiotic and biotic factors) 3

4 Trophic Levels A trophic level is just a predominant feeding level for an organism Organisms that practice photosynthesis or chemosynthesis are considered producers because they produce food Organisms which eat other organisms are consumers Consumer Subgroups Depending on what you consume, you can be classified as different levels of consumer Primary Consumer (herbivore, frugivore) Deer, Butterflies, Elephant, etc. Secondary Consumer Tertiary Consumer Decomposers Decomposers are consumers Commonly bacteria and fungi Also organisms which consume dead organisms (detritivores or detritus feeders) These organisms cycle all the chemicals back into the ecosystem There is very little if any waster from decomposer recycling 4

5 Food Chains & Food Webs Food chains show the direct path of energy as it proceeds up the trophic levels Food webs show the complex series of interactions between individuals, showing many different paths energy can take Food webs are multiple interconnected food chains 5

6 Chains and Webs Thermodynamics The reason we can have chains and webs is because energy is conserved from interaction to interaction. Most of the energy is lost as heat, but some (10%) get passed on 6

7 Biomass and Energy Biomass is the total mass of the dried organisms in that trophic level Autotrophs contain the greatest biomass on the planet As you go up in trophic levels the biomass levels drop considerably based on the 2 nd law of thermodynamics Gross Productivity Gross Primary Productivity (GPP) The rate at which an ecosystem s producers convert solar energy into chemical energy in the form of biomass Measured in energy production per unit area per time 7

8 Net Productivity Net Primary Productivity The rate at which producers use photosynthesis to produce and store energy minus the rate at which they use some of the energy through cellular respiration Ultimately this value limits the amount of consumers available in higher trophic levels. Productivity Gross Photosynthetic rate Net Photosynthetic rate minus respiration Example How much money you make How much you make minus how much you spend The balance you have 8

9 Biogeochemical Cycles The major nutrient cycles are essential for life. Matter has to recycle throughout the natural processes in the ecosystem, if not we would have run out of essential nutrients Major cycles to know: Water Carbon Nitrogen Phosphorus Sulfur Water 9

10 Carbon Nitrogen 10

11 Phosphorus 11

12 Sulfur 12