Download Ecosystems and Biomes

Ecosystems: What They are
(Chapter 2)
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Emphasis in
Chapter 2
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Table 2-2
Biosphere: Earth from the moon
Bioshere: all the earth with all of its environments
Biomes of the World: groupings of similar ecosystems
Ecosystems: Communities of organisms that
interact with one another and with their abiotic
environment.
ecosystem
Biota
(living)
abiotic environment
(non-living)
Ecotones: A transitional region between two adjacent ecosystems that
contains some of the species and characteristics of each one and also
contains species of its own.
Ecosystem Structure: how the parts
fit together
Trophic Structure: major feeding
relationships between organisms
autotrophs
heterotrophs
Organisms: Energy Sources
• Producers: plants and bacteria
– derive energy from inorganic sources
• phototrophs & chemotrophs
• Consumers: grazers, carnivores,etc.
– derive energy from living organisms
(organic sources)
• Decomposers: fungi, scavengers, etc.
– derive energy from dead organic matter
(organic sources)
Organic: materials made from the
bodies of living organisms, made
mostly from bonded Carbon
Inorganic: not from living
organisms, e.g. air water minerals
Producers: Toledo
Energy changes in organisms and ecosystems (Fig 3-12)
Green plant photosynthesis
Fig 2-4
Consumers: Herbivores = animals that eat plants
Wildilfe Africa — www.wildlifeafrica.co.za
Consumers: Carnivores = animals that eat animals
Wildilfe Africa — www.wildlifeafrica.co.za
This carnivore is ~ 1mm long!!
http://www.microscopy-uk.org.uk/mag/wimsmall/extra/rotif2.html
Detritivores & Decomposers
Various web sources
Energy Flow: Food Web
John Wiley — Resource Manager CD-ROM
Biomass Pyramid
• All organic matter = biomass
• ~10% of energy transfers from 1
level to the next
– Respiration, not digested
• Lower level production must be
larger to support upper levels
• The lower you eat, the more of
you there can be!
In class exercise
1) Write down everything you ate for dinner last night (or
today’s breakfast if you cant remember dinner).
2) Assign each item to a trophic level.
Be prepared to share answers to the following
questions:
1) What was your primary trophic level? Was this a
“typical” meal for you?
2) What impact might there be if you fed higher or lower
in the food web?
Original ~ 1971
Examines
politics/environmental
consequences of feeding
high on food chain
Early promoter of
vegetarianism
What is the polar bear doing?
Fig 2-11b
Non-feeding relationships
Symbiosis: unlike organisms living together
parasitism
(one benefits, at
expense of
other)
commensalism
(one benefits,
other
unaffected)
mutualism
(both benefit)
http://www.glfc.org/slft.htm
Lampreys entered
Great Lakes via canal
system
 Devastated lake
trout populations
A very strange case of parasitism
http://daphne.palomar.edu/wayne/ww0701.htm#Angler
 Deep sea anglerfish at very low density, hard to find a mate
 Female releases pheromone to attract male
 In some spp. when male finds female he attaches and
becomes parasitic
Parasitism, Symbiosis, Predation, & Deceit
Wrasse clean
parasites from
large fish. Large
fish doesn’t eat
the wrasse
(mutualism)
large fish have invertebrate parasites
cleaner
mimic gains
access to
large fish and
takes a bite
(parasitism &
deceit)
Competition: plants or animals may
compete to use the same resource, land,
water, nutrient, etc……
Flower in a weedy
garden will do better
if you remove the
weeds (competition)
Ecosystem Engineers
Organisms that directly or indirectly modulate the
availability of resources other than themselves to other
species, by causing physical state changes in biotic or
abiotic materials. In so doing, they modify, maintain
and or create habitats
Jones et al. 1994
 Examples extensively studied, e.g. beaver, but only
recently recognized as important category of interactions
http://sevilleta.unm.edu/data/species/mammal/profile/american-beaver.html
Fig 2-13
Law of the Minimum/Law of limiting factors - Liebig's Law
Justus von Liebig, generally credited
as the "father of the fertilizer
industry", formulated the law of the
minimum: if one crop nutrient is
missing
or deficient, plant growth will
:
be poor, even if the other elements are
abundant.
Liebig likens the potential of a crop to
a barrel with staves of unequal length.
The capacity of this barrel is limited
by the length of the shortest stave (in
this case, phosphorus) and can only be
increased by lengthening that stave.
When that stave is lengthened,
another one becomes the limiting
factor.
Survival Curve: Limits of Tolerance (Fig 2-17)
% NPP Co-opted by humans
Vitousek et al. (1986) estimate % of global NPP used by humans
1) estimate organic material used by people &
domestic animals
3.2% NPP
2) (1) + organic material used in altered systems,
includes land clearing, pastureland, & crop land
30.7% terrestrial NPP, 2.2% aquatic NPP
3) (2) + NPP lost due to human activities, pollution,
acid deposition, soil erosion
38.8 % terrestrial NPP, 24.8 overall NPP
•Neolithic Revolution
–Agriculture developed w/ permanent settlements
–Increase in population (reliable food)
•Industrial Revolution
–Modern world, energy by fossil fuels
–Concentration of wastes
–Even more population growth
•Environmental Revolution
–Need for sustainable human systems
–Need to reduce and/or reuse wastes