September 21, 2014
Ecology
• Ecology: study of how organisms interact with one another and with their nonliving environment> Matter classified
into levels to understand interactions.
September 21, 2014
Organisms and Species
• Organism: any form of life. Most fundamental unit of ecology.> Single cell microorganisms to multicellular
organisms• Species: groups of organisms that resemble one
another in appearance, behavior, chemistry, and genetic makeup. > How are species classified?
http://simple.wikipedia.org/wiki/Tree_of_life_%28biology%29#mediaviewer/File:Simplified_tree.png
Based on nutrition, cell structure, appearance, developmental features, and most recently: genetics and molecular features.
September 21, 2014
Naming Species
• Species are named using binomial nomenclature> Genus species
– italicized– Genus capitalized– species NOT capitalized– Example: Homo sapiens– Example: Equus ferus
http://en.wikipedia.org/wiki/Human#mediaviewer/File:Farmer_plowing_in_Fahrenwalde,_Mecklenburg-Vorpommern,_Germany.jpg
September 21, 2014
Diversity of Species
• ~1.4 million species identified• Estimated 10-15 million
most # of species
Microorganisms
Natural Services:• Nitrogen fixation• Decomposition• Photosynthesis• Natural pest
control
Other Services:• Fermentation• Antibiotics• Digestion
September 21, 2014
Population
• Population: group of interacting individuals of the same species occupying a specific area> genetic diversity> habitat: where population lives> distribution or range: where we can find a
species– Range can change
http://www.savetigersnow.org/problem
September 21, 2014
Community, Ecosystem, and Biosphere
• Community: consists of all the population of different species that live and interact in a particular area
• Ecosystem: Community where population of different species interact with one another and with their nonliving environment of matter and energy
• Biosphere: All of the earth's ecosystems together
http://www.niehs.nih.gov/research/supported/dert/programs/justice/http://en.wikipedia.org/wiki/Biosphere
September 21, 2014
The Four Spheres
http://astro.hopkinsschools.org/course_documents/earth_moon/earth/earth_science/biosphere/biosphere.htm
http://www.isws.illinois.edu/nitro/biggraph.asp
September 21, 2014
http://astro.hopkinsschools.org/course_documents/earth_moon/earth/earth_science/biosphere/biosphere.htm
The Atmosphere
• Atmosphere: thin layer of air around the planet.
• Troposphere: Layer closes to earth, 17 km above sea level.> Contains majority of air> Where weather occurs> 78% N2; 21% O2
• Stratosphere: Stretches 17-48 km above sea level (31 km thick)> O3 layer filters out UV light
• Mesosphere• Thermosphere• Exosphere
> To "outer space"http://www.esrl.noaa.gov/gmd/education/lesson_plans/
September 21, 2014
http://astro.hopkinsschools.org/course_documents/earth_moon/earth/earth_science/biosphere/biosphere.htm
The Hydrosphere
• Hydrosphere: Consists of earth's water> Liquid water (surface +
underground)> Solid water (polar ice, icebergs,
permafrost)> Water vapor (gas, in
atmosphere)
September 21, 2014
http://astro.hopkinsschools.org/course_documents/earth_moon/earth/earth_science/biosphere/biosphere.htm
The Lithosphere
• Lithosphere: earth's crust and upper mantle> nonrenewable fossil fuels and
minerals> renewable soil chemicals
September 21, 2014
The Biosphere
• Biosphere: Interaction of all living things and nonliving components of earth.
http://astro.hopkinsschools.org/course_documents/earth_moon/earth/earth_science/biosphere/biosphere.htm
Just the living stuff
Living stuff and nonliving stuff
September 21, 2014
Life on Earth Depends on 3 factors
• Flow of high-quality energy> Sun --> living organisms --> heat
• Cycling of matter or nutrients> Earth is a closed system to matter
• Gravity> Holds atmosphere and moves
chemicals between various spheres.
September 21, 2014
Solar Energy
• Most energy is reflected by atmosphere or absorbed by chemicals, dust, and clouds in atmosphere.
• 80% that gets through warms troposphere and cycles water
• 1% generates winds• 0.1% photosynthesis• Greenhouse effect
> warms troposphere
September 21, 2014
Regulating Populations
• Each population has a range of tolerance: range of variations in physical and chemical environment that it can survive in.> High tolerance for some things but low for others> Highly tolerant species survive in many habitats
and conditions
September 21, 2014
Regulating Populations
• 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.> limiting factor: one factor is more important in
regulating population than others> *Population control
Examples of limiting factors:• Precipitation• Nutrients: N, K, minerals• Temperature• Sunlight• Oxygen (in water)• Salinity
September 21, 2014
Energy Flow and Matter Recycling in Ecosystems
• matter recycling• one-way energy flow
September 21, 2014
Energy Flow and Matter Recycling in Ecosystems
• Producers (autotrophs): make their own food from energy from the environment> Photosynthesis: Plants, use sunlight to produce
carbohydrates– Balanced equation:
> Chemosynthesis: Bacteria, use energy from chemicals like hydrogen sulfide (H2S) in deep sea vents.
September 21, 2014
Energy Flow and Matter Recycling in Ecosystems
• Consumers (heterotrophs): feed on other organisms > Primary consumers -herbivores> Secondary consumers-carnivores> Third and higher level consumers> Omnivores-feed on plants and animals> Decomposers-biodegrade dead organisms into
simpler inorganic compounds.> Detritivores-feed on waste or dead bodies
September 21, 2014
All organisms (including plants) have to use respiration to use chemical energy.
Getting Energy
• Two ways for organisms to use chemical energy gained through eating or photosynthesis> aerobic respiration: use oxygen to convert
nutrients to carbon dioxide and water> anaerobic respiration: Fermentation! Break
down organic compounds without oxygen--products are other compounds such as CH4, C2H6O, C2H4O2, H2S
September 21, 2014
Energy flow
• Food chain: Shows sequence of organisms, each of which is a source of food for the next.> Trophic level:
feeding level• Food web: complex
network of interconnected food chains. More realistic.
• *Arrow always points towards flow of energy
*In this food web, identify the producer, two primary consumers, two secondary consumers, and one tertiary consumer.
September 21, 2014
Energy flow
• Biomass: dry weight of all organic matter contained in organisms at a particular trophic level (or some sample)> Measure of amount of chemical energy stored in
that trophic level• Ecological efficiency: percentage of usable energy
transferred as biomass from one trophic level to the next.> 2-40% (Average 10%)> Relatively low
September 21, 2014
Energy flow
• Ecological efficiency averages around 10% > Most of what is eaten/digested is lost as heat.> Rest not consumed (death and decay), undigested
(feces) > Successive trophic levels have less usable energy
available.> Limits # of levels
• Pyramid of energy flow: shows energy available at each trophic level and cumulative loss of usable energy.
• What kind of diet will support the most number of people on earth? Why?
September 21, 2014
Energy flow
• Pyramid of numbers: Shows you the # of individual organisms at each trophic level.
• Pyramid of biomass: Shows you the amount of biomass at each trophic level.
• *Usually bottom is widest
http://www.bbc.co.uk/schools/gcsebitesize/science/add_gateway_pre_2011/
greenworld/energyflowrev1.shtml
http://www.bbc.co.uk/schools/gcsebitesize/science/add_gateway_pre_2011/
greenworld/energyflowrev1.shtml
http://en.wikipedia.org/wiki/Food_web#mediaviewer/File:EcologicalPyramids.jpg
September 21, 2014
NPP = GPP - R
Productivity of Producers
• Productivity of producers supports ecosystems. • Gross primary productivity (GPP): Rate at which
producers convert solar energy to biomass• Net primary productivity (NPP): Rate at which
producers convert solar energy to biomass minus the rate at which they use some for respiration (R)> Ultimately limits the # of consumers that can
survive on the earth.
September 21, 2014
Materials available to you for Lab #1: Measuring GPP and NPP• Work in groups of 3 (5 groups)• Each group can have a 3x3 plot of grass• Aluminum foil• "Drying oven"• Digital scale• water• scissors• dirt (already in plots)• any other common lab materials you may want (ask
me)
September 21, 2014
Nutrient Cycles
• Energy flows in one direction through ecosystems but nutrients are cycled.
• Nutrient cycles or biogeochemical cycles move nutrients through air, water, soil, rock, and living organisms.
• For each of the cycles, you should understand the forces/mechanisms that move nutrients from one form to another, the sinks (storage), and how human activities affect that cycle.> Water cycle> Carbon cycle> Nitrogen cycle> Phosphorous cycle> Sulfur cycle
Divide into groups of 3. Each group needs to prepare a presentation that explains the pertinent information for their assigned cycle. You guys are responsible for each other's learning!
September 21, 2014
Soil
• Soil: A thin covering over most land that is a mixture of eroded rock, mineral nutrients, decaying organic matter, water, air, and microorganisms (yeay!)> basis of life on land (nutrients!)
• Formation of soil:> weathering of bedrock
– Physical– Chemical– Biological
> Addition of decaying organic matter– Lichen – Succession!
September 21, 2014
Ecological services provided by soil
• Retains and delivers nutrients and water for producers.• Physical support for plants.• Water storage.• Water purification. Water percolates through soil.
(Gravity!)• Decompose and recycle biodegradable wastes. (Nutrient
cycling)• Removes CO2 from atmosphere, stores as organic C
compounds.*Human activities are accelerating natural soil erosion.
©Blue River Technologyhttp://nsf.gov/news/mmg/mmg_disp.jsp?med_id=75881&from=search_list
September 21, 2014
Soil Horizons
• Mature soils (developed over a long time) are arranged in horizontal layers called soil layers.> each layer has a distinct texture and composition> soil profile: cross section> Mature soils have atleast 3 layers
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http://en.wikipedia.org/wiki/Soil_horizon#mediaviewer/File:SOIL_PROFILE.png
September 21, 2014
Soil Horizons: Top TWO layers contain most organic matter and water.
• O horizon: (Surface litter layer) fallen leaves, twigs, waste, fungi, other organic material (undecomposed or partially decomposed). Looks brown or black.
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http://en.wikipedia.org/wiki/Soil_horizon#mediaviewer/File:SOIL_PROFILE.png
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Soil Horizons: Top TWO layers contain most organic matter and water.
• A horizon: (topsoil) porous, and contains humus (partially decomposed dead plants and animals) mixed with inorganic materials (clay, silt, sand)> holds on to water and nutrients (plant roots!)> Fertile soil needed for agriculture
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http://en.wikipedia.org/wiki/Soil_horizon#mediaviewer/File:SOIL_PROFILE.png
> Dark brown/black topsoil is rich in N and organic matter
> red, yellow, gray is low in organic matter
September 21, 2014
Soil Horizons: lower layers contain most of the inorganic material
• B horizon (Subsoil) and C horizon (parent material) contain most of inorganic matter> rock, sand, silt, clay, gravel
• Bedrock sits under C horizon
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http://en.wikipedia.org/wiki/Soil_horizon#mediaviewer/File:SOIL_PROFILE.png
September 21, 2014
Other soil fun facts:
• Spaces/pores between particles contain air (nitrogen and oxygen) and water. Why do plants need oxygen?
• Infiltration = movement of water into the soil surface
• Percolation =downward movement of water through soil matrix.> leaching = infiltration dissolves minerals and
organic matter, carries to lower layers• Soil is a mixture of 3 kinds of particles:
1. clay (very small) --> sticky2. silt (medium) --> smooth, like flour3. sand (large) --> Gritty> Determines soil texture> Loam is ideal soil for plant growth. Mixture of
all three--crumbly, spongy, with clumps of particles.
September 21, 2014
Biodiversity
• Biodiversity: Can be described by functional diversity, ecological diversity, genetic diversity, and species diversity.
• Why do we care about biodiversity?> resources
– raw materials– medicine
> services– air and water quality– fertility of soil– waste disposal, control pests
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