- Population: individuals of same species in same general area. Has geographic boundaries and population size. Key traits: density (individuals per unit of area or volume) and dispersion (uniform, clumped, random).

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- Population individuals of same species in same
general area. Has geographic boundaries and
population size. Key traits density
(individuals per unit of area or volume) and
dispersion (uniform, clumped, random).
- Demography studies changes in population
size. Births and immigration () deaths and
emigration (-).
- Life histories affect reproductive output and
survival rate, thus population growth. Trade-offs
between survival and reproduction. Semelparity
(big-bang reproduction), iteroparity (repeated
reproduction).
- Population growth exponential (J-shaped,
idealized, occurs in certain conditions) and
logistic (S-shaped. little more realistic,
carrying capacity). K-selection.
Density-dependent selection. r-selection.
Density independent selection.
- Density-dependent changes in birth and death
rates usually slow down population growth rate.
Natural populations are characterized by
instability due to interaction of biotic and
abiotic factors. In some populations they result
in regular boom-and-bust cycles.
-Human population growth, age pyramids,
ecological footprint.
CHAPTER 52 pages 1151-1153, 1156-1171
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Study Guide
1- Understand all the concepts in the guide, do
not memorize the examples. 2- Read the pages in
the book to look at other examples and further
understand the concepts. 3- Study the answers to
questions written by students and discussed in
class
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Community. All the organisms of all the species
inhabiting an area.
Plant communities apparently determined by chance
occurrence of species with similar requirements.
Unclear in animal communities.
The properties and structure of a community are
defined by its species composition and the
interactions between the species.
Interspecific Interactions Competition -/-
Predation (includes herbivory and parasitism)
/- Mutualism / (obligatory or facultative
facilitation) Commensalism /0 Key in
shaping communities competition, predation and
mutualism.
Species interactions involved in determining
trophic structure, dominant and keystone species,
and community control. All affect community
structure.
Trophic structure. Feeding relationships between
organisms. Food chain, trophic levels and food
web. Food webs have few trophic levels
energetic and dynamic stability hypotheses.
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Dominant species. Control in community due to
abundance. Keystone species. Control in community
due to ecological role. Community
organization. Bottom-up model. Changes in
community structure controlled by bottom trophic
levels (competition and available food). Top-down
model. Changes in community structure controlled
by upper trophic levels (predation).
Communities are dynamic, constantly changing, due
to disturbance. Humans are the greatest agents of
disturbance.
Ecological succession- Transitions in species
composition over ecological time. Primary
succession- It begins in a virtually lifeless
area where soil has yet not formed. Secondary
succession- Occurs where an existing community
has been cleared by some disturbance that leaves
the soil intact.
CHAPTER 53 pages 1174-1191
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Ecosystem. All the organisms living in a
community AND the abiotic factors with which they
interact.
Ecosystem Dynamics 1- Energy flow Primary
production gross and net aquatic
(light and nutrients). terrestrial
(climate and nutrients). Secondary
production gross and net production
and trophic efficiencies biomass and number
pyramids green world hypothesis. 2-
Matter (chemical) cycling Biogeochemical
model. Water, carbon, nitrogen. Role
of decomposers. Vegetation regulation.
CHAPTER 54 pages 1198-1214
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What is conservation biology?
Levels of biological diversity (biodiversity).
genetic, species, ecosystem diversity.
Why preserve biodiversity?
Where preserve biodiversity? Terrestrial and
marine biodiversity hotspots.
Biodiversity loss and poverty are linked
problems. How to preserve biodiversity?
What are the major threats to biodiversity?
Habitat destruction and fragmentation farming.
Introduced species. Overexploitation.
Other human impacts climate change
CHAPTER 55 pages 1224-1229
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- Is a forest or grassland considered a uniform
distribution?
- When calculating population sizes, do you count
migratory species?
- Do we know the carrying capacity of the world
for humans?
- When determining human population growth, do
the only consider natural death or all causes?
- In the barnacle example, are you saying that
Balanus is better suited to the environment and
that if desiccation was not a problem at the
higher water level, they would force out the
Chthamalus?
- Assuming two species occupy the same ecological
niche, why couldnt they both co-exist assuming
they were equally fit?
- Wouldnt ash and other material be
nutrient-rich and counted as soil, therefore
making it secondary succession?
- What happens to the rest of the light energy if
only 1 is used?
- How would omnivores be classified in consumer
nomenclature?
- If organic and inorganic materials are only
recycled, where are they from?
- Is there any way to artificially produce
photosynthesis to limit CO2?
- If we need 2,000 calories per day and maybe
half go out as feces, does that mean that we use
only 10 calories for growth per day?