Chapter 3: Ecology and Ecosystems! - Oak Park Unified ...

September 21, 2014

Chapter 3: Ecology and Ecosystems!

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.

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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.

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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

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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

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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

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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

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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

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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/

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The Atmosphere

http://ds9.ssl.berkeley.edu/lws_gems/3/graph_1.htm (c) UC Regents

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The Hydrosphere

• Hydrosphere: Consists of earth's water> Liquid water (surface +

underground)> Solid water (polar ice, icebergs,

permafrost)> Water vapor (gas, in

atmosphere)

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The Lithosphere

• Lithosphere: earth's crust and upper mantle> nonrenewable fossil fuels and

minerals> renewable soil chemicals

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The Biosphere

• Biosphere: Interaction of all living things and nonliving components of earth.


Just the living stuff

Living stuff and nonliving stuff

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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.

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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

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Ecosystem Components

• Biomes and aquatic life zones• Abiotic and biotic factors

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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

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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

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Energy Flow and Matter Recycling in Ecosystems

• matter recycling• one-way energy flow

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• 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.

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• 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

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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

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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

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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?

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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.

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Productivity of Producers

• GPP and NPP vary in ecosystems

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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)

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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!

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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

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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

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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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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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> Dark brown/black topsoil is rich in N and organic matter

> red, yellow, gray is low in organic matter

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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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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.

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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

September 21, 2014

HIPPOAcronym to remember 5 causes of species decline and premature extinction

• H: habitat destruction and degradation• I: invasive species• P: Pollution• P: human population growth• O: Over exploitation

Chapter 3: Ecology and Ecosystems! - Oak Park Unified ...

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