Download Ecology Notes

Today’s Plan: 5/4/2010
 Bellwork: Housekeeping/Test
corrections (10 mins)
 AP Lab 12-DO
 Ecology notes
Today’s Plan: 5/5/2010
 Bellwork: Discuss what we’re
accomplishing in the lab (10 mins)
 Finish DO Lab Data collection (40
mins)
 Notes (the rest of class)
Today’s Plan: 5/6/2010
 Bellwork: Finish AP Lab 12 Data
collection (20 mins)
 Finish AP Lab 12 questions and Test
corrections (30 mins)
 Continue with notes (the rest of
class)
Today’s Plan: 5/7/2010
 Bellwork: Work on the “Can we feed
the world’s population?” sheet (30
mins)
 Notes (the rest of class)
Today’s Plan: 5/10/2010
 China Video (60 mins)
 Finish misc. work (the rest of class)
Today’s Plan: 5/11/2010
 Finish Ecology Notes (30 mins)
 Entry document for Final project (15
mins)
 Class K/NTK list (15 mins)
 Grouping and norm establishment
(the rest of class)
Today’s Plan: 5/12/2010
 Bellwork: Q&A (10 mins)
 Ecology test (the rest of class)
 If you finish early, work on your
project!
5/13-5/19/2010
 Work with your group on your final
project
 I’ll put out a workshop sign up for
your NTKs each day. The last 30
mins, I’ll do the workshops you ask
for.
5/20-21
 Prepare for your presentations (5
mins)
 Group project presentations (the rest
of class)
Ecology
 This is the study of the distribution,
abundance, and interactions of
organisms within their environments.
 Levels of ecology:





Organism
Population
Community
Ecosystem
Biosphere
Figure 50-1
Organismal ecology
Population ecology
How and why does
population size
change over time?
How do individuals
interact with each
other and their
physical environment?
Each female salmon
produces thousands
of eggs. Only a few
will survive to
adulthood. On
average, only two
will return to the
stream of their birth
to breed
Salmon migrate
from saltwater
to freshwater
environments
to breed
Community ecology
Ecosystem ecology
How do species
interact, and what are
the consequences?
Salmon are prey as
well as predators
How do energy
and nutrients
cycle through
the environment?
Salmon die and then
decompose, releasing
nutrients that are used
by bacteria, archaea,
plants, protists, young
salmon, and other
organisms
Population Ecology



Demography-the study of poulations over time, including
categories into which the organism falls
For individuals in populations:
 Life expectancy/Life tables
 Immigration/emigration
For whole populations:
 Density=# individuals/area
 Dispersion=where you find the individuals in that area
 Age Structure=Bar graph showing ages and genders of
individuals in the population
 Reproductive rate, r (growth rate)=births-deaths/N
 N=population size
 Survivorship curve (3 types)
 Biotic potential=maximum growth possible for the
population under ideal conditions (includes things like
reproductive age, clutch size, frequency of reproduction,
survival rate of offspring)
Figure 50-30a
Distribution of cattle is limited by distribution of tsetse flies.
Distribution of tsetse fly
(red)
The two distributions
have little overlap
(purple)
Distribution of cattle
(blue)
Figure 52-1-Table 52-1
Figure 52-15
Developed country
(Sweden)
Developing country
(Honduras)
2050
projections
2000 data
2050 projections
2000 data
Figure 52-2a
Three general types of survivorship curves
Limiting factors
 Limiting factors are elements of an ecosystem that
are in short supply and therefore set limits on
population size
 Carrying Capacity (K)-maximum number of individuals
that can occupy an ecosystem
 Density-dependent limiting factors-factors whose
limiting effects increase as population density
increases (ex: disease, famine, etc). Some cause an
increase in competition.
 Density-independent limiting factors-factors whose
limiting effects are not tied to population density (ex:
natural disasters, climate, etc)
Growth models
 Exponential model-also known as a J curve. Assumes
that populations can grow without limit
 Logistic model-also known as an S curve. Assumes
that populations know what K is, and will act
accordingly
 This changes the reproductive rate equation:
 Change N/Change t=rN(K-N/K)
 Notice, K is taken into consideration here
 Reality-models are only as good as their assumptions,
which means that the graph of real population growth
is slightly different.
Figure 52-7a
Density dependence: Growth rate slows at high density.
Carrying capacity
Later growth
falls to zero
Early growth
is rapid
Growth begins
to slow
Growth and Life History
 These growth models are associated with 2
kinds of life-strategies for organisms:
 r-selected species=these exhibit rapid,
exponential growth. These are often called
opportunitstic species because they quickly
invade an area, reproduce and die. Offspring
mature quickly and are small. (ex: grasses,
insects)
 K-selected species=these are species whose
populations are relatively stable, usually around
K. They produce a small number os offspring
that are large and require lots of care. They
reproduce repeatedly (ex: humans)
Human Population growth
 Human population worldwide is reaching 9 billion. It
was just 3 billion 100 years ago.
 Why the rapid rise?
 Increases in food supply and travel-humans have
domesticated, bred, and fine-tuned agriculture (from
hunter-gatherer to farmer)
 Reduction in disease-advances in medicine, like
vaccines, antibiotics, etc have dropped the death rate
and increased the successful birth rate
 Reduction in wastes-sewage systems and water
treatment have reduced health hazards
 Expansion of habitat-better housing, clothing, etc
have made it easier to live in more places
Figure 52-16-Table 52-2
Figure 52-17
Low
Population cycles: Predator/Prey
 Predator/prey describes a relationship
between a hunter and an individual that is
eaten.
 In general, changes in the prey population
cause similar changes in the predator
population since the predator is dependent
on the prey. Just keep in mind, the prey
are usually predators of the producers, so
their population changes are often due to
seasonal changes in their prey population.
Figure 52-12
The hare-lynx populations cycle every
11 years, on average; the size of the lynx
population lags behind that of the hares
Hare
Lynx
Community Ecology


Habitat-the area that an organism inhabits within an
ecosystem
Niche-the role of the organism within the environment1
species per niche




Gause’s principle of competitive exclusion=when 2 species
try to occupy the same niche, there will be competition
until one species leaves or dies
Resource partitioning=some species can coexist even
though they appear to be competing for the same
resources. They are occupying slightly different niches by
using the resources in different ways.
Character displacement (niche shift)=as a result of
resource partitioning, certain characteristics allow
organisms to obtain their partitioned resources more
successfully
Realized niche=This is the niche that the organism
occupies b/c of resource partitioning. If there were no
competitors, they would otherwise occupy their
fundamental niche, but because of niche overlap, they
must adjust
Figure 53-2
Consumptive competition
These trees are competing for water
and nutrients.
Chemical competition
Few plants are growing under these
Salvia shrubs.
Preemptive competition
Space preempted by these barnacles is
unavailable to competitors.
Territorial competition
Grizzly bears drive off black bears.
Overgrowth competition
The large fern has overgrown other individuals
and is shading them.
Encounter competition
Spotted hyenas and vultures fight over a kill.
Figure 53-4a
Competitive exclusion in two species of Paramecium
Paramecium
aurelia
Paramecium
caudatum
Figure 53-4b
Competitive exclusion occurs when competition is
asymmetric …
Asymmetric
competition
Higher fitness
Lower fitness
Symmetric
competition
Same
fitness
Figure 53-4c
… and niches overlap completely.
Species 1: Strong competitor
Species 2: Weak competitor,
driven to extinction
Figure 53-4d
When competition is asymmetric and niches do not overlap
completely, weaker competitors use nonoverlapping resources.
Species 1
Species 2
(strong competitor) (weak competitor)
Fundamental
niche
Realized
niche
Figure 53-3
One species eats seeds of a certain size range.
Partial niche overlap: competition for seeds of
intermediate size
Species 2
Species 1
Trophic Relationships
 These are the feeding relationships in an ecosystem.
 Recall from biology that energy transfer between
trophic levels is inefficient-only 10% of the energy is
transferred, which affects the amount of biomass and
the numbers of individuals at each trophic level. This
also means that food chains are rarely more than 5
trophic levels.
 Food chain: primary producerprimary
consumersecondary consumertertiary
consumerdetritovores (decomposers)
 Food webs are overlapping food chains in an
ecosystem.
 Recall the following terms: carnivore, herbivore,
omnivore
Figure 54-1
External energy
source, usually
solar energy but
also chemical energy
Primary producers (autotrophs)
Organisms that can synthesize
their own food
Abiotic environment
The soil, climate, atmosphere,
and the particulate matter
and solutes in water
Consumers
Organisms that eat
other living organisms
Decomposer
Organisms that feed
on dead organisms or
their waste products
Figure 54-5
Trophic
level
Feeding
strategy
5
Quaternary
consumer
Decomposer
food chain
Grazing
food chain
Cooper’s hawk
4
3
2
1
Tertiary
consumer
Robin
Cooper’s hawk
Earthworm
Robin
Bacteria, archaea
Cricket
Secondary
consumer
Primary
decomposer
or consumer
Primary
producer
Dead maple leaves Maple tree leaves
Figure 54-6
Cooper’s hawk
Robin
Fox
Alligator lizard
Arrows show direction
of energy flow: from
organism consumed
to consumer
Earthworm
Bracket fungus
Rotting log
Millipede
Bacteria, archaea
(many species)
Puffball
Dead leaves
(many species)
Pillbugs
Insect larvae
(maggots)
Dead animals
(many species)
Cricket
Maple tree
leaves
Figure 54-7
Production of biomass
(g/m2/year)
Tertiary consumers 3
Secondary consumers
Primary consumers
and decomposers
Primary
producers
30
10%
15%
200
Efficiency of
energy transfer
20%
1000
Types of predator/prey
relationships
 True predators-kills and eats another
animal
 Parasites-are only predatory if they kill
their host
 Parasitoid-insects that lay eggs on a host.
The larvae are parasitic to the host
 Herbivores-yes, they’re technically
predators. Some are seed-eaters
(granivores), some eat grasses (grazers),
and some eat other plant material
(browsers)
Avoiding Predation
 Organisms have evolved many mechanisms for
avoiding predators.
 Secondary Compounds-toxic chemicals produced by
plants that can make herbivores sick
 Camouflage (cryptic coloration)-helps the animal
blend into it’s surroundings (some predators use this
as well to help them hunt)
 Aposematic coloration (warning coloration)-a bright
color pattern that advertises that the organism should
be avoided (ex: wasp/bee stripes)
 Mimicry-organisms resembling each other (shortens
the predator’s learning curve)
 Mullerian mimicry-dangerous organisms resemble
each other
 Batesian mimicry-organisms without a defense
mechanism resemble a dangerous organism
Figure 53-12
Cottonwood tree felled by beavers
Resprouted trees have more
defensive compounds.
Survival of beetle larvae
placed on ant mound
Figure 53-10
Prey and predator
Blue mussels
Crabs
Correlation between predation rate and prey defense
Figure 53-9
Constitutive defenses of animals vary.
Camouflage: blending into the background Schooling: safety in numbers
Weaponry: fighting back
Mimicry can protect both dangerous and harmless species.
Müllerian mimics
Paper wasp
Bumblebee
Batesian mimics
Honeybee
Hornet moth
Wasp beetle
Hoverfly
Symbiosis-a different kind of
relationship
 In a symbiotic relationship, organisms
closely associate with one another.
There are 3 types of symbiosis:
 Parasitism-1 organism benefits, the
other is harmed
 Commensalism-1 organism benefits, the
other is neither harmed nor benefitted
 Mutualism-both organisms benefit
Figure 53-16-Table-53-1
Coevolution in Relationships
 Organisms often respond to changes
in other organisms through
coevolution.
 For example, hummingbirds find
nectar by color, so the flowers that
attract them are tube-shaped, are
bright red, and have virtually no
scent
 Often, plants can only be pollinated
by one type of pollinator, so they
evolve together
Biodiversity
 This is also called species diversity and can
be discussed in terms of
 Species richness-number of different species in
the community
 Relative abundance of different species in the
community
 This is a measure of heath of an ecosystem
 Diseases are specific to the organism
 If 1 food source dies, there are others, etc
Figure 53-25
Community 2
Community 3
Species richness: 6
6
5
Species diversity: 0.59
0.78
0.69
Community 1
A
B
C
Species
D
E
F
Figure 55-4
Hotspots in terms of species richness of birds
Hotspots in terms of endemic species of birds
Hotspots in terms of high proportion of endemic plants and high threat
High Impact Species in
Communities




Keystone Species-These are not necessarily abundant in a
community, but play a part in many interactions within the
community. You can tell a keystone species by removing it
from the ecosystem and viewing the impact. (ex: sea
otters, if removed don’t keep sea urchins in check, and
there’s less kelp)
Invasive Species-These are species that invade (usually by
being introduced by humans) an ecosystem and replace the
species that are naturally there
Dominant Species-These are the most abundant species in
an ecosystem, and have the most biomass
Foundation Species-These are also called Ecosystem
engineers, and they cause physical changes in their
environments. Beavers are examples of this type of
species.

Facilitators are foundation species that have a positive impact
on the environment
Figure 53-18
Predator: Pisaster ochraceous
Prey: Mytilus californianus
Figure 55-7
Invasive species increase competition.
Purple loosestrife is crowding out native
organisms in North American marshes.
Invasive species introduce disease.
Invasive species increase predation.
An introduced fungus has virtually wiped out
the American chestnut.
The brown tree snake has extinguished dozens
of bird species on Guam.
Figure 53-19
P. ochraceous
(keystone predator)
present
P. ochraceous
(keystone predator)
absent
Community Change
 Succession-a series of more-or-less orderly changes
in an ecosystem over time. Begins with a pioneer
species (usually an r-selected species) and ends with
a climax community (stable)
 In general, as organisms inhabit the area, they
changes the texture, pH, and water potential of the
soil, as well as establish competition for resources as
the area becomes crowded
 Primary Succession-occurs on a substrate that has
never before supported life.
 Secondary Succession-occurs on a substrate that has
gone through some sort of disturbance
Succession on land
 In primary succession, generally starts with
lava flow or sand.
 Pioneer for lava-lichens
 Pioneer for sand-grasses
 In secondary succession, you can start at
any point in the successional process,
usually a field.
 These used to be thought of as a
predictable series of changes, however,
there are instances that are more random
and less orderly b/c they’re affected by
climate, which species happen to arrive
first, etc.
Figure 53-21-1
Old field
Disturbance (plowing) ends, site is
invaded by short-lived weedy species.
Pioneering species
Figure 53-21-2
Weedy species are replaced by longer-lived
herbaceous species and grasses.
Early successional
community
Shrubs and short-lived
trees begin to invade.
Mid-successional
community
Figure 53-21-3
Short-lived tree species mature;
long-lived trees begin to invade.
Late-successional
community
Long-lived tree
species mature.
Climax community
Succession in Water
 This happens when you start with a
lake or pond that changes to a
marsh-like state.
 The marsh is followed by meadow,
with lots of grasses.
 Finally, there’s a climax community of
native vegetation
Ecosystem Ecology

Biogeochemical Cycles-this is the flow of important elements through the
ecosystem.

Hydrologic cycle-mainly an abiotically-driven cycle.
 Reservoirs-ocean, air, groundwater, glaciers
 Assimilation-plants absorb water from the soil, animals drink water
and eat organisms
 Release-transpiration, evaporation, etc.

Carbon cycle-mainly biotically-driven and tied to atmospheric CO2
levels that cause the greenhouse effect
 Reservoirs-atmosphere, fossil fuel, peat, organic material (like
cellulose)
 Assimilation-photosynthesis, animals eating plants and each other
 Release-respiration and decomposition

Nitrogen cycle-also a biotically driven cycle dependent heavily on
bacteria
 Reservoirs-atmospheric N2, soil (nitrates, nitrites, ammonium,
amonia)
 Assimilation-nitrogen fixation by bacteria, nitrification by bacteria
 Release-denitrification by bacteria, decomposition, animal waste

Phosphorous cycle-again, a biotically-driven cycle
 Reservoirs-rocks and ocean sediments
 Assimilation-plants absorb phosphates and are eaten by animals
 Release-decomposition, animal waste
Figure 54-13
THE GLOBAL WATER CYCLE
All values in 1018 grams per year
Evaporation
from ocean:
319
Net movement of water vapor by wind: 36
Precipitation
over ocean:
283
Evaporation,
transpiration:
59
Precipitation
over land: 95
Percolation
Water table
(saturated soil)
Figure 54-14
THE GLOBAL CARBON CYCLE
All values in gigatons of carbon per year
Net uptake via
photosynthesis,
chemical processes:
1.5
Atmosphere: 778 (during 1990s)
Net uptake via
photosynthesis
by plants: 3.0
Land-use change
(primarily deforestation):
1.6
Fossil-fuel use:
6.3
Organisms, soil,
litter, peat: 2190
Organisms, chemical
processes in ocean:
40,000
Aquatic ecosystems
Rivers (erosion):
0.8
Terrestrial ecosystems
Human-induced changes
Figure 54-16
THE GLOBAL NITROGEN CYCLE
All values in gigatons of nitrogen per year
Atmospheric nitrogen (N2)
Internal
cycling:
8000
Bacteria in mud
use N-containing
molecules as energy
sources, excrete N2:
310
Nitrogen-fixing
cyanobacteria:
Runoff: 36
15
Mud
Permanent burial: 10
Protein and
nucleic acid
synthesis
Industrial
fixation: 100
Lightning
and rain: 3
Internal
cycling:
1200
Decomposition of
detritus into ammonia
Nitrogen-fixing bacteria
in roots and soil: 202
Biomes
 These are ecosystems that have
characteristic biotic and abiotic factors
 Land Biomes are largely determined by
latitude (except desert which is determined
by climate)
 As you move from the poles toward the equator,
biodiversity and biomass increase. The length of
the growing season also increases.
 Water Biomes are determined by salinity
and depth
Land Biomes
 In the tropics:
 Rain forest-200-400
cm of rain annually
 Savanna-30-50 cm of
rain annually
 In the temperate
zone:
 Deciduous forest-70200 cm of rain
annually
 Grassland-30-100 cm
of rain annually
 Chaparal-30-50 cm of
rain annually (coastal
region)
 Northern Coniferous
forest (Taiga)-30-100
cm of rain annually
 Tundra-20-60 cm of
rain annually
 Desert-occurs at any
latitude-less than 30
cm of rain annually
Figure 50-9
Barrow
Dawson
Chicago
Konza Prairie
Yuma
Belém
Figure 50-23
North pole
Small amount of
sunlight per unit area
Low angle of
incoming sunlight
Moderate angle of
incoming sunlight
Sunlight directly
overhead
Large amount of
sunlight per unit area
Figure 54-11
Boreal forest: Accumulation of
detritus and organic matter
Tropical wet forest: Almost no
organic accumulation
Organic
matter
Organic
matter
Figure 50-12
Tropical wet forests are
extremely rich in species
Figure 50-11
Figure 50-18
Temperate forests are
dominated by broadleaved deciduous trees
Figure 50-17
Figure 50-16
Grasses are the
dominant lifeform
in prairies and
steppes
Figure 50-15
Figure 50-20
Boreal forests are
dominated by
needled-leaved
evergreens, such
as spruce and fir
Figure 50-19
Figure 50-22
Arctic tundra is dominated
by cold-tolerant shrubs,
lichens, and herbaceous
plants
Figure 50-21
Figure 50-26
Air rises over mountains
and cools; rain falls
East
Dry air creates
desert conditions
West
Moisture-laden air blows
onshore from Pacific Ocean
Cascade
Mountains
This area is in
a rain shadow
Figure 50-14
Saguaro cacti are a prominent
feature of the Sonoran Desert in
the southwestern part of
North America
Figure 50-13
Water Biomes
 Freshwater:
 Lakes
 Streams and Rivers
 Wetlands
 Brackish:
 Estuaries
 Marine:
 Intertidal Zone
 Oceanic Pelagicsplit into the photic
and aphotic zones
 Coral reefs-always
in the photic zone
 Benthic-ocean
bottom
Figure 50-5
Bogs are stagnant and acidic.
Marshes have nonwoody plants.
Swamps have trees and shrubs.
Figure 50-3
Photic
zone
Aphotic
zone
Primary Productivity
 This is the amount of light energy
converted to chemical energy in an
ecosystem.
 Gross Primary productivity-is the total
primary productivity of the ecosystem
 Net Primary productivity-is the gross
primary productivity- the energy used by
producers for respiration (R)
 Formula for net primary productivity:
 NPP=GPP-R
Figure 54-3
NPP per unit area
Aquatic
Terrestrial
Area covered, by
ecosystem type
Total NPP
Human Impact on the Biosphere
 Human activity over time has been damaging to the
biosphere.
 Ecology is really a study of balance, and as the human
population has grown, our wastes and byproducts
have thrown off that balance.
 There have been, in recent years, efforts to
reestablish the balance and conserve our resources.
 Ex: Prior to the 1980s, CFCs were common
propellants used in household goods. As a result of
human use of CFCs, they built up in the atmosphere,
reacting with ozone (O3), and causing holes in the
ozone layer. This layer surrounds the planet and
shields us from damaging UV radiation. As a result of
banning CFCs, and using safer alternatives, the holes
in the ozone layer are repairing themselves.
Climate change
 Human activities have caused a buildup of
CO2 in the atmosphere. Of course, CO2 is
a greenhouse gas, which means that we
have additional heat building up in our
atmosphere
 Data indicates that the world is getting
warmer, which sparks many problems like
raising sea levels, changing weather
patterns that could decrease agricultural
output, change the trophic structure of our
oceans and land
Figure 54-15b
Recent changes in atmospheric CO2 recorded in Hawaii
At Mauna Loa, atmospheric
CO2 concentrations are high
in winter and low in summer,
forming annual cycles
Figure 54-19
Cold-water copepods are declining in the North Atlantic.
Flowering times for some species in midwestern
North America are earlier in the year.
Great
Britain
Cold-water
copepods
Warm-water
copepods
Baptista flowers
Figure 54-21
Much of the ocean is stratified by density and temperature.
Global warming increases the density gradient, making it
less likely for layers to mix.
Surface layer: Water is much warmer, less dense
Surface layer: Water is warm, less dense
Density
gradient
Nutrient-rich
water is brought
to the surface
by currents
Benthic zone: Water is 4°C, highest density
Much
steeper
density
gradient
Currents are less likely
to bring nutrient-rich
water to surface,
against the steeper
density gradient
Benthic zone: Water is 4°C, highest density
Pollution
 Obviously, this causes destruction of water, air, and
land resources, as they become fouled by waste.
 This has obvious negative side-effects for orgnisms on
the planet, but there are 2 important issues
associated with pollution that aren’t always discussed.
 Biological magnification-while energy decreases as it
moves up the food chain, pollutants and toxins, like
DDT, concentrate.
 Eutrophication-believe it or not, this IS a bad thing.
Over-fertilization nourishes the water, causing algal
blooms. Not only can these be toxic to animals, but
they are r-strategists, so they die, sink, and are
decomposed at the bottom of bodies of water (mainly
freshwater). Decomposition is an oxygen-consuming
process, which leaves the bottom waters anoxic,
causing fish-kills
Other Environmental Problems
 Acid Rain-Sulphur-containing compounds
belched from smokestacks turn into
sulphuric acid in the atmosphere
 Deforestation-clear-cutting of forests for
logging and expanding human population.
This is particularly bad b/c the nutrients in
tropical rain forests are in the canope.
 Desertification-overgrazing of grasslands
bordering deserts turns these into deserts.
 All of these can lead to endangerment of or
reduction in species and biodiversity.
Figure 55-10
The devastation of deforestation
Satellite view of deforestation in Rondônia, Brazil
1975
2001
Figure 55-6
Terrestrial
Freshwater
Marine
Sustainable Practices
 These are things that humans can do
to reduce our impact on the
biosphere.
 Examples include: reforestation,
smoke-stack filters, reduction of fossil
fuel consumption, smart use of
fertilizers, plowing and strip cropping
to reduce erosion, use of biological
methods for controling pests,
establishing protected areas, etc