Biology notes – Ecosystems and populations
I. Biomes/the Biosphere (chapter 3)
A. Components of an ecosystem
1. physical
2. living
B. organisms have adaptations to the abiotic and biotic components of their
environment; this is explained by natural selection (p. 66)
C. energy flow and food webs – 3-5
1. 10% rule – fig. 3-11 and 3-12
2. bioaccumulation/biomagnification
D. chemical/nutrient cycles
1. water (fig. 3-15)
2. carbon (fig. 3-17)
3. nitrogen (fig. 3-18)
4. human use can alter these cycles
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burning fossil fuels released excess CO2 into the air
synthesis and application of fertilizers effects oxygen levels
in water
E. Community and ecosystem ecology
1. definition of community and ecosystem
2. relationships between species (examples and more info)
a. competition
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competitive exclusion (fig. 4-7)
b. predator-prey
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mimicry
camoflage
co-evolution
keystone species
c. symbiotic relationships
a. mutualism (Fig. 4-9)
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match flowers with their
pollinators
b. commensalism
c. parasitism
F. Disturbance and succession - fig. 4-12 and 4-13
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Glacier Bay National Park has glaciers that have retreated dramatically in
the past 200 years (more on Glacier Bay)
vegetation at Mt. St. Helens is growing back after the 1980 eruption
the role of fires
II. climate effects local biomes - section 4.1
1. seasons
2. temperature
3. moisture/precipitation
4. rain shadows
A. Aquatic biomes
1. oceans (fig. 4-22)
2. estuaries (fig. 4-21)
3. coral reefs
4. wetlands (swamp, marsh, bog, etc)
5. rivers
B. terrestrial biomes – overview fig. 4-18, p. 110-116
1. tropical forests (some are rain forest)
2. temperature deciduous forest
3. boreal forest
4. savanna
5. temperate grasslands
6. tundra
7. desert
8. chaparral
9. biomes vary by latitude and also by altitude (moving up a
mountain is like moving north from the equator)
III. Population dynamics – chap 5
A. definition of population
B. measuring populations and their distribution - fig 5-2
C. population growth depends on birth and death rates
1. exponential growth produces a “J-shaped” curve (fig. 5-4)
2. growth is eventually limited by resources, producing an “Sshaped” curve (fig. 5-5)
3. the maximum sustainable number is the carrying capacity
4. growth can be limited by various factors (fig 5-6)
5. various cycles are typical of different populations (example lynx and hare - see also fig. 5-8)
D. human population growth
1. history – fig. 5-11
2. both numbers and consumption rates contribute to
environmental problems
3. population growth progresses through a demographic transition
(fig. 5-12)
4. Age structure diagrams help compare different countries
population (fig. 5-13)
E. when we use biological resources (fishing, farming, hunting) we need to
understand population growth in order to use them sustainably
IV. Humans in the biosphere (chap 6)
A. History of human resource use
1. hunter-gatherers
2. agriculture
3. industry and urban development
B. Resources
1. renewable vs. non-renewable
2. land and soil
3. forests
4. fisheries
5. air and water
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pollution – water and air
C. preserving biodiversity
1. habitat loss, introduced species, and overexploitation are the
chief problems
2. reasons for preservation
3. distribution of diversity varies around the globe
4. Endangered Species Act and the role of habitat preservation
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habitat fragmentation is a concern
creating “edges” and corridors affects biodiversity
D. global climate change
1. natural greenhouse effect and increase in CO2
2. possible consequences
3. ozone depletion