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63 Cards in this Set
- Front
- Back
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Inputs |
exchanges from surrounding environment into the ecosystem |
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Outputs |
exchanges from inside the ecosystem to the surrounding environment |
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Closed ecosystem |
no inputs Bog |
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Open ecosystem |
recieves inputs Stream most are this |
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First law of thermodynamics |
All energy is constant and cannot be created or destroyed, only change form |
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Second law of thermodynamics |
When energy is transferred or transformed, part of it assumes a form that cannot pass on any further
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Entropy |
the reduction in potential energy |
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Living systems |
open systems, sun provides constant input of energy, counteracting entropy |
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Exothermics |
reaction losses energy release heat |
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Endothermic |
reaction absorbs energy absorbs heat |
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Potential energy |
energy of position |
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Kinetic energy |
energy of motion |
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Chemical energy |
potential energy held in the bonds between atoms |
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Photosynthesis |
autotrophs or primary producers produce food, fix carbon CO2 + H2O + Sun => C6H12O6 + 6O2 |
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Cellular Respiration |
Heterotrophs Release chemical energy Organisms use chemical energy stored during photosynthesis O2 used to convert C6H12O6 => H2O +CO2 + Energy |
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Gross Primary Production (GPP) |
Assimilation of energy by autotrophs
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Net Primary Production (NPP) |
Energy remaining after respiration and used to generate biomass available for heterotrophs |
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Energy Fixing not dependent on the sun |
bacteria used in chemical energy fixation near hydrothermal vents |
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Productivity |
rate at which organic matter is created by photosynthesis |
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Biomass |
amount of organic matter present at any given time |
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Units of productivity |
Energy/area/time = kcal/m2/yr Mass of OM/area/time = g/m2/yr |
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Standing Crop Biomass |
Grams of accumulated OM in a given area at a given time = mass of OM/area = g/m2 |
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NPP increases with increasing temp and precip on land and light and nutrients in aq systems |
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Climate determines NPP Closer to the equator, longer growing season Lack of water lowers PP |
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1. Dry matter production 2. Precipitation |
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1. NPP 2. Length of photosynthetic period (days) |
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1. Dry matter productivity 2. Temperature °C |
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Light and nutrient availability limit PP in ocean Light decreases with depth |
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Compensation depth |
depth where photosynthesis and respiration balance out |
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Macronutrients |
nutrients required in relative large amounts NPC |
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Micronutrients |
nutrients needed in smaller amounts |
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Limiting nutrients in aquatic systems |
N or P sometimes Fe |
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Redfield ratio |
ratio of C to N to P for plants 106:16:1 |
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Autochthonous |
OC produced within system |
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Allochthonous |
OC produced outside of the system |
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Plant energy allocation and PP |
Energy put into leaf production increases PP Energy put into stem and root decreases PP |
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High NPP |
Ecosystems whose plants rapidly convert solar energy into biomass |
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Secondary production |
Heterotrophs consume primary producers some energy lost as heat energy used to maintain body systems left over energy used for growth and reproduction |
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Daily, seasonal, years variations in NPP |
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High secondary productivity |
Birthrate of population and growth rate of individual is highest |
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PP limits SP |
All PP is consumed by grazers or decomposers |
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PP available to SP varies |
Grasslands vs forests easily accessible to grazers vs only woody biomass within reach |
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Assimilation |
Converting PP into SP |
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Assimilation efficiency |
ratio of assimilation to ingestion |
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Production efficiency |
ratio of production to assimilation |
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Variations in assimilation efficiency
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Endotherms > ectotherms Carnivores (80%) > herbivores (20-40%) |
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Variations in producition efficiency |
Invertibrates (30-40%) Ectothermic vertebrates (10%) Endothermic vertebrates (1-2%) |
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Body size of endotherms and production efficiency
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Larger = higher prodction efficiency SA/V |
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Production rates affected by |
quality of food feeding strategy energy spent acquiring food |
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(a) Energy flow (b) Matter cycling |
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Types of food chains |
Grazing Detrital |
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Grazing food chain |
Primary producers eaten directly by grazers |
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Detrital food chain |
Primary producers broken down by decompsers and detritus feeds comsumers |
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Primary Consumers (Grazing) |
Second trophic level Herbivores |
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Secondary Consumers (Grazing) |
Third trophic level Carnivores |
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Tertiary Consumers |
Forth trophic level predators at the highest trophic level consume secondary consumers |
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Omnivores |
consumers that eat both plants and animals |
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Detritivores |
scavenge waste products or dead bodies (detritus) Millipedes Fiddler crabs |
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Decomposers |
Break down leaf litter and other non-living material enhancing topsoil and recycling nutrients Fungi, bacteria |
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Consumption efficiency |
Consumption ratio of ingestion to production at the next trophic level Production in one trophic level limits the production in the level above it |
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Available energy and food chains |
Decreases up the food chain, less energy availabl in each trophic level Each level contains 10% of the energy of the trophic level below it |
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Top Predators |
Rare, constrained by lack of energy at the top of the food web |
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NPP and trophic levels |
NPP controls higher trophic levels and vice versa grazing and predators |
