ecology
Post on 11-May-2015
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ECOLOGY•The study of living organisms and their interaction with the nonliving environment
Historical Background•Ecology
•Eco = “house”
ology = “study of”
•BIOTIC ABIOTIC
Realms of Ecology•Organisms
•Populations
•Communities
•Ecosystems
•Biome
•Biosphere
What Ecologists Study
•Concerned with levels of organization ABOVE population
The Biosphere
• The portion of the earth where living organisms exist– If the earth were an apple, the
biosphere would be no thicker than the skin
Atmosphere
• The troposphere– Surface to 17 km (11 miles) up– Contains most of the oxygen and nitrogen
• The stratosphere– 17 to 48 km up– Contains most of the O3
– Screens out all UV-C– Screens out most UV-B– Screens out some UV-A
Hydrosphere
• All the water on the earth– Liquid water• Surface• underground
– Ice• Polar ice• Icebergs• Ice in frozen soil
–Water vapor in the atmosphere
Lithosphere
• Crust and upper mantle– Contains all fossil fuels– Contains all usable minerals– Contains all nutrients for plant life
What Sustains Life on Earth?
Life on Earth depends on three interconnecting factors
• One way flow of energy– From the sun– Through plants and animals
• Cycling of matter– All nutrients must be recycled repeatedly
• Gravity– Allows the planet to hold its atmosphere– Causes downward movement of chemicals in
cycles
How the Sun Helps Sustain Life
• Lights and warms the planet
• Supports photosynthesis
• Powers matter cycling
• Drives climate and weather systems
How the Sun Helps Sustain Life
• Lights and warms the planet
– Earth receives about 1/1,000,000,000 of the suns energy output
– 34% reflected back into space
– The remaining 66%• Warms the troposphere and land• Evaporates water• Generates winds
How the Sun Helps Sustain Life
• Supports photosynthesis– Creates carbohydrates – Creates oxygen– Speeds decomposition
How the Sun Helps Sustain Life
• Powers matter cycling– Carbon cycle– Nitrogen cycle–Water cycle– Oxygen cycle– Phosphorous cycle
How the Sun Helps Sustain Life
• Drives climate and weather systems– Distributes heat– Distributes fresh water
Natural Greenhouse Effect
• Most solar radiation is degraded into heat
• Greenhouse gasses keep the heat around the planet– Water vapor– Carbon dioxide– Methane– Nitrous oxide– ozone
• Without the greenhouse effect, Earth would be as cold as Mars
Ecosystem Concepts
• Biomes – large regions of land characterized by a distinct climate and specific animal and especially plant species– Forests– Desserts– Grasslands– Jungles
Ecosystem Concepts
• Biomes - consist of two components– abiotic • Water• Air• Solar energy• nutrients
– Biotic (biota)• Animals• Plants• microorganisms
Ecosystem Concepts
• Ecotones – biomes do not have clear-cut edges. They blend into one another
– Ecotones contain a mixture of organisms from each biome and frequently species found nowhere else
– Ecotones are more biologically diverse than either of the bordering biomes
Ecosystem Concepts
• Ecotones – biomes do not have clear-cut edges. They blend into one another
– Ecotones contain a mixture of organisms from each biome and frequently species found nowhere else
– Ecotones are more biologically diverse than either of the bordering biomes
Deciduous Forest/River Ecotone
Aquatic/Marine life Zones
• Fresh water life zones– Lakes & ponds– Streams & rivers
• Marine life zones– Estuaries– Coastlines– Coral reefs– Deep oceans
Abiotic Limitations
• Abiotic
• Water – how much or how little
• Solar energy – shade or sun
• Nutrients – rich or poor
Range of Tolerance
• There is an optimum range of each abiotic component of a biome for each species
• Individuals in a population may have slightly different tolerances
Law of Tolerance
The levels, abundance and distribution of a species in an ecosystem are determined by whether the levels of one or more physical or chemical factors fall within the ranger tolerated by that species.
Translation: Don’t expect to find polar bears in Tahiti
Limiting Factor Principle
Too much or too little of any abiotic factor can limit or prevent growth of a population, even if all other factors are at or near the optimum range of tolerance.
Translation: If the restaurant serves really spicy food, don’t look for Anglos
Limiting Factor Principle
• Too much of a particular abiotic factor can also be a limiting factor
• Limiting factors can change
Limiting Factor Principle
• Aquatic or marine life zones also have limiting factors
– Sunlight– Dissolved oxygen– Nutrient availability– Salinity
Living Components of the Biome
• Metabolism – all living creatures capture and transform matter and energy from their environment to supply their needs for survival, growth and reproduction
Living Components of the Biome
All living things are divided into two groups
• Producers – make their own food from components obtained from the environment
• Consumers – obtain nutrients and energy by consuming other organisms or their remains
ProducersAutotrophs
Most producers capture sunlight and abiotic nutrients to produce carbohydrates (such as glucose (C6H12O6) in a process called Photosynthesis
Photosynthesis
Carbon dioxide + water + solar energy glucose + oxygen
CO2 + 6 H2O + solar energy C6H12O6+ 6 O2
Chemosynthesis
Hydrogen sulfide + carbon dioxide + geothermal heat nutrients
H2S + CO2 + geothermal heat nutrients
ConsumersHeterotrophs
Obtain their energy and nutrients by consuming other organisms or their remains
ConsumersHeterotrophs
All these organisms consume living prey• Herbivores – (primary consumers) feed
directly on producers• Carnivores – (meat eaters) feed on other
consumers– Secondary consumers – feed only on primary
consumers– Tertiary consumers – (higher level consumers)
feed on other carnivores
• Omnivores – feed on both plants and animals
HerbivoresPrimary Consumers
CarnivoresSecondary Consumers
Heterotrophssome feed on the dead or dying
• Scavengers – feed on dead animal carcasses
• Detritivores – feed on waste, parts of carcasses or cast off parts
• Detritus feeders – feed on partially decomposed organic matter
• Decomposers – (mostly bacteria and fungi) break down dead organic materials to simpler inorganic compounds
Aerobic Respiration and Photosynthesis
• Photosynthesis Energy + Carbon Dioxide + water glucose +
oxygensunlight + CO2 + H2O C6H12O6 + O2
• Aerobic Respiration glucose + oxygen carbon dioxide + water +
Energy C6H12O6 + O2 CO2 + H2O + Energy
Energy Cycling
• Solar energy is collected by plants (producers)
– Most of the energy from the sun is lost as heat
• Primary consumers (herbivores) eat the plants– Most of the energy is lost as
heat
• Secondary consumers (carnivores) eat the primary consumers– Most of the energy is lost as
heat
Energy Cycling
• Tertiary consumers eat the secondary consumers– Most of the energy is lost as
heat
• Detritivores consume the dead and dying– Most of the energy is lost as
heat
Energy Cycling
As you pass up the energy pyramid, the number of organisms decreases.
At each step in the pyramid, ~90% of the energy is lost as heat
Food Chains
• Simplified constructs used to show energy flow in the ecosystem
• Food chains do not exist in nature
Food Webs
• Food webs are more realistic representations of nature
• Organisms rarely feed at only one trophic level
Available Energy
• How many trophic levels are present depends on how much energy is available in an ecosystem– There are rarely more than four or five
trophic levels in an ecosystem• The amount of energy an ecosystem
produces is called the Net Primary Productivity
• Measured in kcal/m2/yr or g/m2/yr
Net Primary ProductivityEquals
Rate at which producers store chemical energy as biomass
Minus
(produced by photosynthesis)
Rate at which producers use chemical energy stored as biomass
(through aerobic respiration)
Net Primary Productivity
Different EcosystemsProduce Different Biomass
Most Productive
• Estuaries• Swamps/marshes• Tropical rainforests
Least Productive
• Open ocean• Tundra• Desert
Human Biomass Usage
• Humans have taken over, disturbed or degraded ~73% of the earths’ land surface
• Humans use, waste or destroy ~27% of the earths’ total potential net primary productivity and ~40% of the total potential net primary productivity of terrestrial ecosystems
Matter Cycling
• Energy is an open system– Energy enters the system as sunlight
(low entropy) and is degraded and dispersed (high entropy) as organisms use it
• Matter is a closed system– All matter is recycled in one of three
ways
Matter Cycles
There are three major types of nutrient recycling
1. Hydraulic cycle (ex. Water cycle)2. Atmospheric cycle (ex. Carbon
cycle)3. Sedimentary cycle ( ex.
Phosphorous)
Hydraulic Cycle
• Water evaporates and cycles through the biosphere– Local– Regional– global
Atmospheric Cycle
• A large portion of the nutrient exist in the atmosphere and cycle rapidly through soil, organisms and back to the atmosphere– Local– Regional– Global
Sedimentary Cycle
Earths’ crust is the main storehouse. Elements move from the land to the seabed then back to land through geological uplift and volcanic action
– global
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