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.
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?
Based on
nutrition, cell
structure,
appearance,
developmental
features, and most
recently: genetics
and molecular
features.
http://simple.wikipedia.org/wiki/Tree_of_life_%28biology%29#mediaviewer/File:Simplified_tree.png
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.j
September 21, 2014
Diversity of Species
• ~1.4 million species identified
• Estimated 10-15 million
Microorganisms
Natural Services:
• Nitrogen fixation
• Decomposition
• Photosynthesis
• Natural pest
control
most # of species
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
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://astro.hopkinsschools.org/course_documents/earth_moon/earth/earth_science/biosphere/biosphere.htm
http://www.esrl.noaa.gov/gmd/education/lesson_plans/
September 21, 2014
The Atmosphere
http://ds9.ssl.berkeley.edu/lws_gems/3/graph_1.htm (c) UC Regents
September 21, 2014
The Hydrosphere
• Hydrosphere: Consists of earth's
water
> Liquid water (surface +
underground)
> Solid water (polar ice, icebergs,
permafrost)
> Water vapor (gas, in
atmosphere)
http://astro.hopkinsschools.org/course_documents/earth_moon/earth/earth_science/biosphere/biosphere.htm
September 21, 2014
The Lithosphere
• Lithosphere: earth's crust and
upper mantle
> nonrenewable fossil fuels and
minerals
> renewable soil chemicals
http://astro.hopkinsschools.org/course_documents/earth_moon/earth/earth_science/biosphere/biosphere.htm
September 21, 2014
The Biosphere
• Biosphere: Interaction of all living things and nonliving
components of earth.
Just the
living stuff
Living stuff
and
nonliving
stuff
http://astro.hopkinsschools.org/course_documents/earth_moon/earth/earth_science/biosphere/biosphere.htm
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
Ecosystem Components
• Biomes and aquatic life zones
• Abiotic and biotic factors
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
September 21, 2014
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
All organisms (including plants) have to
use respiration to use chemical energy.
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://en.wikipedia.org/wiki/Food_web#mediaviewer/
File:EcologicalPyramids.jpg
http://www.bbc.co.uk/schools/gcsebitesize/science/
add_gateway_pre_2011/
http://www.bbc.co.uk/schools/gcsebitesize/science/
add_gateway_pre_2011/
greenworld/energyflowrev1.shtml
greenworld/energyflowrev1.shtml
September 21, 2014
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.
NPP = GPP - R
September 21, 2014
Productivity of Producers
• GPP and NPP vary in ecosystems
September 21, 2014
Materials available to you for Lab #1:
Measuring GPP and NPP
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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
Divide into groups of 3. Each
group needs to prepare a
> Carbon cycle
presentation that explains the
> Nitrogen cycle
pertinent information for their
> Phosphorous cycle
assigned cycle. You guys are
> Sulfur cycle
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 Technology
http://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
User: Zwiadowca21/Wikimedia Commons/CC BY-SA3.0
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.
User: Zwiadowca21/Wikimedia Commons/CC BY-SA3.0
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.
User: Zwiadowca21/Wikimedia Commons/CC BY-SA3.0
• 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
> Dark brown/black
topsoil is rich in N
and organic matter
> red, yellow, gray is
low in organic matter
http://en.wikipedia.org/wiki/Soil_horizon#mediaviewer/File:SOIL_PROFILE.png
September 21, 2014
September 21, 2014
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
User: Zwiadowca21/Wikimedia Commons/CC BY-SA3.0
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) --> sticky
2. silt (medium) --> smooth, like flour
3. 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
September 21, 2014
HIPPO
Acronym to remember 5 causes of species decline and
premature extinction
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H: habitat destruction and degradation
I: invasive species
P: Pollution
P: human population growth
O: Over exploitation