biol 1020: ecology - auburn university · 2014. 11. 18. · what is ecology? ecology is the...
TRANSCRIPT
ECOLOGY
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What is ecology?
Ecology is the scientific study of interactions between ___________
term ecology comes from the Greek oikos, _______, and logos, to study
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biotic and abiotic factors
What are biotic factors? Give examples.
What are abiotic factors? Give examples.
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climate
What is climate?
What abiotic factors are the major components of climate?
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climate
What effects do bodies of water have on climate?
What effects do mountains have on climate?
Include descriptions of how elevation affects temperature, and of rain shadows.
Fig. 52-12
Fig. 52-13
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climate
What effects do seasons have on climate?
Describe what causes seasons; include the terms solstice and equinox in your description.
Fig. 52-10c
March equinox
60ºN
30ºN
0º (equator)
30ºS June solstice
Constant tilt of 23.5º
September equinox
December solstice
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aquatic biomes
List the major aquatic biomes and their defining physical features.
define the following:
photic zone
aphotic zone
benthic zone
Fig. 52-16
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Lakes
• Oligotrophic lakes are nutrient-poor and generally
oxygen-rich
• Eutrophic lakes are nutrient-rich and often
depleted of oxygen if ice covered in winter
• Rooted and floating aquatic plants live in the shallow
and well-lighted littoral zone
• Water is too deep in the limnetic zone to support
rooted aquatic plants; small drifting animals called
zooplankton graze on the phytoplankton
Fig. 52-18a
Fig. 52-18b
Fig. 52-18c
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Wetlands
• A wetland is a habitat that is inundated by
water at least some of the time and that
supports plants adapted to water-saturated soil
• Wetlands can develop in shallow basins, along
flooded river banks, or on the coasts of large
lakes and seas
• Wetlands are among the most productive
biomes on earth and are home to diverse
invertebrates and birds
Fig. 52-18d
Fig. 52-18e
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Streams and Rivers
• The most prominent physical characteristic of
streams and rivers is current
• A diversity of fishes and invertebrates inhabit
unpolluted rivers and streams
• Damming and flood control impair natural
functioning of stream and river ecosystems
Fig. 52-18f
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Estuaries
• An estuary is a transition area between river
and sea
• Salinity varies with the rise and fall of the tides
• Estuaries are nutrient rich and highly
productive
• An abundant supply of food attracts marine
invertebrates and fish
Video: Flapping Geese
Fig. 52-18g
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Intertidal Zones
• An intertidal zone is periodically submerged
and exposed by the tides
• Intertidal organisms are challenged by
variations in temperature and salinity and by
the mechanical forces of wave action
• Many animals of rocky intertidal environments
have structural adaptations that enable them to
attach to the hard substrate
Fig. 52-18h
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Oceanic Pelagic Zone
• The oceanic pelagic biome is a vast realm of
open blue water, constantly mixed by wind-
driven oceanic currents
• This biome covers approximately 70% of
Earth’s surface
• Phytoplankton and zooplankton are the
dominant organisms in this biome; also found
are free-swimming animals Video: Shark Eating a Seal
Fig. 52-18i
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Coral Reefs
• Coral reefs are formed from the calcium
carbonate skeletons of corals (phylum
Cnidaria)
• Corals require a solid substrate for attachment
• Unicellular algae live within the tissues of the
corals and form a mutualistic relationship that
provides the corals with organic molecules
Video: Coral Reef Video: Clownfish and Anemone
Fig. 52-18j
A deep-sea hydrothermal vent community
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Marine Benthic Zone
• The marine benthic zone consists of the
seafloor below the surface waters of the
coastal, or neritic, zone and the offshore
pelagic zone
• Organisms in the very deep benthic, or
abyssal, zone are adapted to continuous cold
and extremely high water pressure
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• Unique assemblages of organisms are
associated with deep-sea hydrothermal vents
of volcanic origin on mid-oceanic ridges; here
the autotrophs are chemoautotrophic
prokaryotes
Video: Hydrothermal Vent Video: Tubeworms
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aquatic biomes
Describe the process of turnover in a lake, and why it is important.
What is eutrophication, and what are some likely consequences of it?
Fig. 52-17-1
Fig. 52-17-2
Fig. 52-17-3
Fig. 52-17-4
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terrestrial biomes
List the major terrestrial biomes and their characteristic vegetation types and climate.
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terrestrial biomes
define the following:
climograph
ecotone
Be sure that you can interpret a climograph.
Fig. 52-19
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Terrestrial Biomes
• Terrestrial biomes can be characterized by
distribution, precipitation, temperature, plants,
and animals
Fig. 52-21a
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Tropical Forest
• In tropical rain forests, rainfall is relatively constant, while in tropical dry forests precipitation is highly seasonal
• Tropical forests are vertically layered and competition for light is intense
• Tropical forests are home to millions of animal species, including an estimated 5–30 million still undescribed species of insects, spiders, and other arthropods
Fig. 52-21b
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Desert
• Precipitation is low and highly variable, generally less
than 30 cm per year; deserts may be hot or cold
• Desert plants are adapted for heat and desiccation
tolerance, water storage, and reduced leaf surface
area
• Common desert animals include many kinds of snakes
and lizards, scorpions, ants, beetles, migratory and
resident birds, and seed-eating rodents; many are
nocturnal
Fig. 52-21c
A savanna in Kenya
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Savanna
• Savanna precipitation and temperature are
seasonal
• Grasses and forbs make up most of the ground
cover
• Common inhabitants include insects and
mammals such as wildebeests, zebras, lions,
and hyenas
Fig. 52-21d
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Chaparral
• Chaparral climate is highly seasonal, with cool
and rainy winters and hot dry summers
• The chaparral is dominated by shrubs, small
trees, grasses, and herbs; many plants are
adapted to fire and drought
• Animals include amphibians, birds and other
reptiles, insects, small mammals and browsing
mammals
Fig. 52-21e
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Temperate Grassland
• Temperate grasslands are found on many
continents
• Winters are cold and dry, while summers are
wet and hot
• The dominant plants, grasses and forbs, are
adapted to droughts and fire
• Native mammals include large grazers and
small burrowers
Fig. 52-21f
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Northern Coniferous Forest
• The northern coniferous forest, or taiga,
extends across northern North America and
Eurasia and is the largest terrestrial biome on
Earth
• Winters are cold and long while summers may
be hot
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• The conical shape of conifers prevents too
much snow from accumulating and breaking
their branches
• Animals include migratory and resident birds,
and large mammals
Fig. 52-21g
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Temperate Broadleaf Forest
• Winters are cool, while summers are hot and
humid; significant precipitation falls year round
as rain and snow
• A mature temperate broadleaf forest has
vertical layers dominated by deciduous trees in
the Northern Hemisphere and evergreen
eucalyptus in Australia
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• Mammals, birds, and insects make use of all
vertical layers in the forest
• In the Northern Hemisphere, many mammals
hibernate in the winter
Fig. 52-21h
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Tundra
• Tundra covers expansive areas of the Arctic;
alpine tundra exists on high mountaintops at all
latitudes
• Winters are long and cold while summers are
relatively cool; precipitation varies
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• Permafrost, a permanently frozen layer of soil,
prevents water infiltration
• Vegetation is herbaceous (mosses, grasses,
forbs, dwarf shrubs and trees, and lichen) and
supports birds, grazers, and their predators
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population ecology
Population ecology is the study of populations in relation to __________
A population is:
define the following:
density
dispersion
range
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population ecology
How does the mark-recapture method to estimate population size work?
Include the formula and definition of the terms in the formula.
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population ecology
What is demography?
define and be able to use/interpret:
life tables
survivorship curves
reproductive tables
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Life Tables
• A life table is an age-specific summary of the
survival pattern of a population
• It is best made by following the fate of a
cohort, a group of individuals of the same age
• The life table of Belding’s ground squirrels
reveals many things about this population
Table 53-1
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Survivorship Curves
• A survivorship curve is a graphic way of
representing the data in a life table
• The survivorship curve for Belding’s ground
squirrels shows a relatively constant death rate
Fig. 53-5
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• Survivorship curves can be classified into three
general types:
– Type I: low death rates during early and middle
life, then an increase among older age groups
– Type II: the death rate is constant over the
organism’s life span
– Type III: high death rates for the young, then a
slower death rate for survivors
Fig. 53-6
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Reproductive Rates
• For species with sexual reproduction,
demographers often concentrate on females in
a population
• A reproductive table, or fertility schedule, is
an age-specific summary of the reproductive
rates in a population
• It describes reproductive patterns of a
population
Table 53-2
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population ecology
define and be able to use/interpret the exponential population growth model
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Exponential Growth
Exponential population growth is population increase under idealized conditions
Under these conditions, the rate of reproduction is at its maximum, called the intrinsic rate of increase
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Equation of exponential population growth:
dN dt
rmaxN
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The J-shaped curve of exponential growth characterizes some rebounding populations
Fig. 53-11
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population ecology
define and be able to use/interpret the logistic population growth model
define and understand the terms K and r
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Exponential growth cannot be sustained for long in any population
A more realistic population model limits growth by incorporating carrying capacity
Carrying capacity (K) is the maximum population size the environment can support
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The Logistic Growth Model
In the logistic population growth model, the per capita rate of increase declines as carrying capacity is reached
We construct the logistic model by starting with the exponential model and adding an expression that reduces per capita rate of increase as N approaches K
dN dt
(K N)
K rmax N
Table 53-3
.
The logistic model of population growth produces a sigmoid (S-shaped) curve
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population ecology
describe K-selection and r-selection
What sort of life tables and survivorship curves would you expect for each type?
Give examples of organisms of each type.
If given a typical life history for an organism be able to categorize it as K-selected and r-selected.
.
K-selection, or density-dependent selection, selects for life history traits that are sensitive to population density
r-selection, or density-independent selection, selects for life history traits that maximize reproduction
Fig. 53-13
Fig. 53-14
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population ecology
List and describe six density-dependent factors known to affect population growth rates.
Describe how population cycles may be linked between predators and their prey.
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Competition for Resources
In crowded populations, increasing population density intensifies competition for resources and results in a lower birth rate
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Territoriality
In many vertebrates and some invertebrates, competition for territory may limit density
Cheetahs are highly territorial, using chemical communication to warn other cheetahs of their boundaries
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Disease
Population density can influence the health and survival of organisms
In dense populations, pathogens can spread more rapidly
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Predation
As a prey population builds up, predators may feed preferentially on that species
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Toxic Wastes
Accumulation of toxic wastes can contribute to density-dependent regulation of population size
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Intrinsic Factors
For some populations, intrinsic (physiological) factors appear to regulate population size
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Human population history and future
Be sure that you understand figures 53.22-26.
What was industrial revolution and how did it affect human population growth?
What is the demographic transition and how does it affect human population growth?
What is the global carrying capacity for humans?
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The Global Human Population
The human population increased relatively slowly until about 1650 and then began to grow exponentially
Fig. 53-23
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To maintain population stability, a regional human population can exist in one of two configurations:
Zero population growth = High birth rate – High death rate
Zero population growth = Low birth rate – Low death rate
The demographic transition is the move from the first state toward the second state
Fig. 53-24
1750 1800 1900 1950 2000 2050
Year
1850
Sweden Mexico
Birth rate Birth rate Death rate Death rate
0
10
20
30
40
50 B
irth
or
de
ath
ra
te p
er
1,0
00
pe
op
le
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The demographic transition is associated with an increase in the quality of health care and improved access to education, especially for women
Most of the current global population growth is concentrated in developing countries
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Age Structure
One important demographic factor in present and future growth trends is a country’s age structure
Age structure is the relative number of individuals at each age
Fig. 53-25
.
Age structure diagrams can predict a population’s growth trends
They can illuminate social conditions and help us plan for the future
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Infant Mortality and Life Expectancy
Infant mortality and life expectancy at birth vary greatly among developed and developing countries but do not capture the wide range of the human condition
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Global Carrying Capacity
How many humans can the biosphere support?
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Estimates of Carrying Capacity
The carrying capacity of Earth for humans is uncertain
The average estimate is 10–15 billion
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Limits on Human Population Size
The ecological footprint concept summarizes the aggregate land and water area needed to sustain the people of a nation
It is one measure of how close we are to the carrying capacity of Earth
Countries vary greatly in footprint size and available ecological capacity
Fig. 53-27
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Our carrying capacity could potentially be limited by food, space, nonrenewable resources, or buildup of wastes
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community ecology
Community ecology is the study of:
A biological community is:
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community ecology
describe the following interspecific interactions in general terms of the +/-/0 system
competition
predation
herbivory
parasitism
mutualism
commensalism
.
community ecology
define the terms
(ecological) niche
resource partitioning
character displacement
.
Ecological Niches
The total of a species’ use of biotic and abiotic resources is called the species’ ecological niche
An ecological niche can also be thought of as an organism’s ecological role
Ecologically similar species can coexist in a community if there are one or more significant differences in their niches
.
Resource partitioning
Resource partitioning is differentiation of ecological niches, enabling similar species to coexist in a community
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Character Displacement
Character displacement is a tendency for characteristics to be more divergent in sympatric populations of two species than in allopatric populations of the same two species
An example is variation in beak size between populations of two species of Galápagos finches
Fig. 54-4
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predation
Describe how these defenses can help animals avoid predation:
camouflage
warning coloration
Batesian mimicry
Müllerian mimicry
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mutualism
What is the difference between obligate and facultative mutualism?
.
community ecology
What is symbiosis?
Which interspecific interactions are types of symbiosis?
.
community ecology
What is keystone species and a pivotal niche?
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community ecology
What is a food web?
How do energetic limits affect food webs/chains?
.
community ecology
Describe
ecological succession
primary succession
secondary succession
.
ecosystems
Diagram the biogeochemical cycles of
water
carbon
nitrogen
phosphorus
Fig. 55-14a
Fig. 55-14b
Fig. 55-14c
Fig. 55-14d
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ecosystems
Describe how biomagnification (biological magnification) of a toxin works in an ecosystem.
Fig. 55-20
.
How we almost killed ourselves:
the ozone hole story
Describe the importance of the ozone layer.
.
How we almost killed ourselves:
the ozone hole story
Describe how human activities led to depletion of the ozone layer.
Fig. 55-24
.
How we almost killed ourselves:
the ozone hole story
Describe what humans have done about the depletion of the ozone layer.
.
How we still might kill ourselves:
global warming
Describe the greenhouse effect and why
CO2 is called a greenhouse gas.
realclimate.org Global cooling myth debunked
AP story
.
How we still might kill ourselves:
global warming
Describe how human activities
increase CO2 in the atmosphere,
the logic behind how that leads to
global warming, and the evidence
that global warming is occurring.
.
How we still might kill ourselves:
global warming
Describe what effects global warming
may have. What is the feed-forward
effect of thawing tundra?
Describe what humans have done about
global warming.
.
biodiversity
Define
ecosystem biodiversity
species biodiversity
genetic biodiversity
Fig. 56-3
.
biodiversity
Describe the value of biodiversity in
maintaining the global ecosystem and biogeochemical cycles
providing unique resources such as food, remediation, drugs
intrinsic value of biodiversity
Fig. 56-5
Fig. 56-6
Fig. 56-4
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The sixth extinction
...or how we are killing lots of things (and perhaps
ultimately ourselves as well)
What is habitat loss and how is it affecting life on Earth today?
What are introduced species and how are they affecting life on
Earth today?
What is overexploitation and how is it affecting life on Earth
today?
Fig. 56-2
Fig. 56-7
Fig. 56-8
(a) Brown tree snake (b) Kudzu
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The sixth extinction
...or how we are killing lots of things (and perhaps
ultimately ourselves as well)
What is overexploitation and how is
it affecting life on Earth today?
.
What is the sixth extinction?
What can humans do about it?