1 Ecosystems Mark Mayo Cypress College Last update 8/27/13

2 Ecology Basics Producers (primary producers) – autotrophic organisms* that are capable of photosynthesis or chemosynthesis Producers (primary producers) – autotrophic organisms* that are capable of photosynthesis or chemosynthesis They make food They make food Most free oxygen in the atmosphere comes from photosynthesis * Most free oxygen in the atmosphere comes from photosynthesis *

3 Ecology Basics Consumers – any organism that consumes producers or other consumers Consumers – any organism that consumes producers or other consumers carnivore – a meat eater; really one that eats another animal (worms and insects are meat too!) carnivore – a meat eater; really one that eats another animal (worms and insects are meat too!) herbivore * – organisms that eats plants only (aka 1 o consumer) herbivore * – organisms that eats plants only (aka 1 o consumer) omnivore – organism that eats plants and animals omnivore – organism that eats plants and animals

4 Ecology Basics Decomposers * – fungi and bacteria who obtain energy by breaking down the remains of organisms Decomposers * – fungi and bacteria who obtain energy by breaking down the remains of organisms Bread MoldInsects Worms

5 Ecology Basics Detrivores – obtains their energy from decomposing particles of organic material Detrivores – obtains their energy from decomposing particles of organic material Snail (aquatic)Mayfly

6 Ecosystem Definition of an ecosystem * – an array of organisms (biotic) and the physical environment (abiotic) in the process of energy transfer ultimately from the sun Definition of an ecosystem * – an array of organisms (biotic) and the physical environment (abiotic) in the process of energy transfer ultimately from the sun It runs on energy input from the sun It runs on energy input from the sun It also needs nutrient inputs from soil It also needs nutrient inputs from soil Energy is not recycled * – passed through levels and lost to environment as heat Energy is not recycled * – passed through levels and lost to environment as heat Nutrients are frequently recycled – some lost Nutrients are frequently recycled – some lost

7 Tropic levels Producer – a plant or organism capable of changing inorganic compounds into organic compounds that can be used for food. Producer – a plant or organism capable of changing inorganic compounds into organic compounds that can be used for food. This is usually a plant * This is usually a plant * Could also be cyanobacteria & some protists * Could also be cyanobacteria & some protists *

8 Tropic levels Primary (1 o) consumer – eats producers (herbivores and omnivores) Primary (1 o) consumer – eats producers (herbivores and omnivores) Secondary (2 o ) consumer – eats primary consumers Secondary (2 o ) consumer – eats primary consumers Tertiary (3 o ) consumer – eats secondary consumers Tertiary (3 o ) consumer – eats secondary consumers

9 Food Chain A linear series of relationships based on tropic level * A linear series of relationships based on tropic level *

10 Food Web A food web is much more complicated than a single chain * A food web is much more complicated than a single chain * Often one organism is prey for several other organisms Often one organism is prey for several other organisms A predator is someone else’s prey A predator is someone else’s prey

11 Food Web

12 Food Web See if you can determine the tropic level of each organism

13 Energy Flow Through the Ecosystem Energy from a primary source (sun) flows in a one-way direction through food webs * Energy from a primary source (sun) flows in a one-way direction through food webs * Grazing food web Grazing food web Sun Sun Producers Producers Herbivores (1 o consumer) Herbivores (1 o consumer) Carnivores (2 o consumer) Carnivores (2 o consumer) Decomposers Decomposers Light arrow = nutrientsBlack arrow = energy

14 Energy Flow Through the Ecosystem Energy from a primary source (sun) flows in a one-way direction through food webs Energy from a primary source (sun) flows in a one-way direction through food webs Detrital food webs Detrital food webs Sun Sun Producers Producers Decomposers Decomposers Detritivores Detritivores

15 Ecological pyramid Definition of ecological pyramid * - graphic representation of the various tropic levels in a way to depict the relative amounts of biomass in each level Definition of ecological pyramid * - graphic representation of the various tropic levels in a way to depict the relative amounts of biomass in each level 90% of the energy is lost at each new level 90% of the energy is lost at each new level

16 Ecological pyramid Producers - eelgrass, algae, other plants (809) Producers - eelgrass, algae, other plants (809) Herbivores (1 o consumers) – fish, turtles, invertebrates (37) Herbivores (1 o consumers) – fish, turtles, invertebrates (37) 2 o consumers - fish invertebrates (11) 2 o consumers - fish invertebrates (11) 3 o consumers) – large-mouth bass, gar (1.5) 3 o consumers) – large-mouth bass, gar (1.5) Decomposers – bacteria, crayfish (5) Decomposers – bacteria, crayfish (5) As you climb the ecological pyramid energy is lost and biomass declines As you climb the ecological pyramid energy is lost and biomass declines

17 Ecological pyramid

18 Biomass Definition of biomass * - the dry weight of all organic matter in a given ecosystem Definition of biomass * - the dry weight of all organic matter in a given ecosystem Plant materials and animal waste used as fuel. Plant materials and animal waste used as fuel.

19 Biological Magnification A pesticide becomes more concentrated as it moves from producers to the various tropic levels A pesticide becomes more concentrated as it moves from producers to the various tropic levels It can become dangerous concentrated to the upper level consumers It can become dangerous concentrated to the upper level consumers

20 Biogeochemical Cycles Hydrologic Cycle or Water Cycle * Hydrologic Cycle or Water Cycle * Precipitation – rainfall, snow, fog, sleet, hail, dew etc. Precipitation – rainfall, snow, fog, sleet, hail, dew etc. Runoff – water that cannot be absorbed and passes by gravity to the lowest level (ocean, lake, stream) Runoff – water that cannot be absorbed and passes by gravity to the lowest level (ocean, lake, stream) Groundwater – water beneath the surface – pools, and rivers Groundwater – water beneath the surface – pools, and rivers Respiration – biological process that uses oxygen and sugar to make energy and releases water Respiration – biological process that uses oxygen and sugar to make energy and releases water Evaporation – physical change of aqueous water to water vapor which is dependent on heat Evaporation – physical change of aqueous water to water vapor which is dependent on heat Transpiration – loss of water directly from plant leaves to atmosphere Transpiration – loss of water directly from plant leaves to atmosphere

21 Biogeochemical Cycles Hydrologic Cycle or Water Cycle

22 Biogeochemical Cycles Carbon Cycle Carbon Cycle Sources of carbon: Sources of carbon: Respiration products Respiration products Burning of fossil fuels Burning of fossil fuels Volcanic eruptions Volcanic eruptions Oceans hold vast amounts of carbon in the form of carbonates Oceans hold vast amounts of carbon in the form of carbonates Plants, animals, soil and the atmosphere hold most carbon Plants, animals, soil and the atmosphere hold most carbon Atmospheric carbon is in the form of carbon dioxide CO 2 Atmospheric carbon is in the form of carbon dioxide CO 2

23 Biogeochemical Cycles CarbonCycle

24 Biogeochemical Cycles Carbon Cycle Carbon Cycle Excessive CO 2 has led to global warming mostly because of the overuse of fossil fuels Excessive CO 2 has led to global warming mostly because of the overuse of fossil fuels Carbon dioxide acts to retain heat like a blanket around the earth Carbon dioxide acts to retain heat like a blanket around the earth Plants reduce atmospheric carbon dioxide and thus reduce global warming! Plants reduce atmospheric carbon dioxide and thus reduce global warming!

25 Biogeochemical Cycles CarbonCycle

26 Biogeochemical Cycles Nitrogen Cycle Nitrogen Cycle Nitrogen (N 2 ) forms 80% of the earth’s atmosphere Nitrogen (N 2 ) forms 80% of the earth’s atmosphere Very few organisms have the ability to break down N 2 and convert it to a form useful to organisms Very few organisms have the ability to break down N 2 and convert it to a form useful to organisms Bacteria, volcanic action and lightning are the primary methods to break down N 2 Bacteria, volcanic action and lightning are the primary methods to break down N 2 Nitrogen is needed for producers to conduct photosynthesis Nitrogen is needed for producers to conduct photosynthesis

27 Biogeochemical Cycles Nitrogen Cycle Nitrogen Cycle

28 Biogeochemical Cycles Nitrogen Cycle Nitrogen Cycle Legumes * are plants that had special bacteria in the roots that are capable of converting atmospheric nitrogen (N 2 ) to fertilizer Legumes * are plants that had special bacteria in the roots that are capable of converting atmospheric nitrogen (N 2 ) to fertilizer Alfalfa in bloom Nodules on roots

29 Biogeochemical Cycles Nitrogen Cycle Nitrogen Cycle Nitrogen fixation: conversion atmospheric nitrogen (N 2 ) to ammonia (NH3) which is quickly converted to NH4+ or the ammonium ion Nitrogen fixation: conversion atmospheric nitrogen (N 2 ) to ammonia (NH3) which is quickly converted to NH4+ or the ammonium ion Bacteria such as Cyanobacteria, Rhizobium and Azotobacter all can perform nitrogen fixation Bacteria such as Cyanobacteria, Rhizobium and Azotobacter all can perform nitrogen fixation These organisms fix 200 million metric tons of nitrogen per year These organisms fix 200 million metric tons of nitrogen per year Plants capable of considerable nitrogen fixation are called legumes – they have a symbiotic relationship with bacteria to achieve nitrogen fixation Plants capable of considerable nitrogen fixation are called legumes – they have a symbiotic relationship with bacteria to achieve nitrogen fixation

30 Biogeochemical Cycles Nitrogen Cycle Nitrogen Cycle Humans use fertilizers to add nitrogen to soil depleted of nitrogen Humans use fertilizers to add nitrogen to soil depleted of nitrogen The problem with fertilizer use is the cost and runoff of nitrogen rich materials into the lakes and streams which acts as a pollutant The problem with fertilizer use is the cost and runoff of nitrogen rich materials into the lakes and streams which acts as a pollutant

31 Biogeochemical Cycles Nitrogen Cycle Nitrogen Cycle Ammonification – bacteria and fungi breakdown organisms to release nitrogen Ammonification – bacteria and fungi breakdown organisms to release nitrogen

32 Biogeochemical Cycles Phosphorus Cycle Phosphorus Cycle Definition of the Phosphorus Cycle - the movement of the element phosphorus from mineralized forms to aqueous forms and then the incorporation into plants and animals Definition of the Phosphorus Cycle - the movement of the element phosphorus from mineralized forms to aqueous forms and then the incorporation into plants and animals Rock formations on land contains phosphate Rock formations on land contains phosphate Erosion takes phosphates from the rocks and moves it to streams and rivers eventually to reach the ocean Erosion takes phosphates from the rocks and moves it to streams and rivers eventually to reach the ocean Phosphates are RARE on earth! * Phosphates are RARE on earth! *

33 Biogeochemical Cycles Phosphorus Cycle Phosphorus Cycle

34 Biogeochemical Cycles Phosphorus Cycle Phosphorus Cycle Plants remove phosphates from soil and concentrate it in their tissues Plants remove phosphates from soil and concentrate it in their tissues Animals gain phosphates when they eat plants Animals gain phosphates when they eat plants Animals lose phosphates in urine and fecal waste Animals lose phosphates in urine and fecal waste

35 Biogeochemical Cycles Phosphorus Cycle Phosphorus Cycle Bird and bat guano is concentrated uric acid and phosphates Bird and bat guano is concentrated uric acid and phosphates

36 Biogeochemical Cycles Phosphorus Cycle Phosphorus Cycle Runoff of human applied fertilizers yield excessive phosphates and nutrients Runoff of human applied fertilizers yield excessive phosphates and nutrients This can lead to algal bloom in streams and lakes This can lead to algal bloom in streams and lakes Algal blooms can rob the lake of nutrients to support other life forms (fish die!) Algal blooms can rob the lake of nutrients to support other life forms (fish die!)