Ecology
Ecology
• Study of the relationships between the living
(biotic factors plants, animals, predators,
microbes, etc) and the non-living (abiotic
factors soil, temperature, pH, light, rainfall,
wind, etc) that occur w/in a specific habitat
Ecosystem
• All the living and non-living factors that interact in
some way w/in a well-defined area at a specific
time
Ex: desert, pond, grassland, forest, tundra
WHAT AFFECTS THE DISTRIBUTION OF THE TERRESTRIAL
BIOMES? CLIMATE, ELEVATION, RAINFALL, DISTANCE FROM
EQUATOR – ALL OF THE THINGS THAT AFFECT CLIMATE!
Abiotic and Biotic Factors
BIOTIC & ABIOTIC FACTORS
Section 4-2
Abiotic Factors
Biotic Factors
ECOSYSTEM
Ecological Niche
• The role or function of an organism w/in a given ecosystem
– Food chain path of energy through trophic levels of an
ecosystem
– Food web complicated, interconnected path of energy
(food chain)
FOOD WEB
Cont. Ecological Niche
1. Producers (Autotrophs)
• Include plants, algae, and some kinds of bacteria
• Carries out photosynthesis process that
synthesizes glucose (sugar) from CO2 and H2O in
the presence of light
• Autotrophic cells produce ALL the food available
to the ecosystem
light
6 CO2 + 6 H2O ------------------------ C6H12O6 + 6 O2
chlorophyll
Cont. Ecological Niche
2. Consumers (Heterotrophs)
• Organisms which utilize nutrients synthesized by
autotrophs (dependent on producers!)
Ex: birds, humans, bats, elephants, butterflies,
giraffes
a. Respiration
– Aerobic (requires O2) breakdown of nutrients and
the production of energy (ATP) and wastes
6 O2 + C6H12O6 -------------------- ATP + 6 H2O + 6 CO2
Cont. Consumers
b. Fermentation
– Anaerobic (does not require O2) breakdown of
nutrients and the production of energy and
wastes
-------- ATP + 2 alcohol + 2 CO2 (yeasts)
C6H12O6 -------- ATP + 2 acetic acid + 2 CO2 (bacteria)
-------- ATP + lactic acid (bacteria)
Cont. Ecological Niche
3. Decomposers (Detritivores/ Saprophytes)
• Includes bacteria and fungi
• Heterotrophic organisms which break down
dead/ decayed organic matter and then recycle
the nutrients (elements) back into the
environment
* NOTE: Observe how the carbon is cycled between
the various organisms that are carrying out
theses basic life reactions
Ex: how matter (non-living) is interacting w/
organisms (living things)
Pyramids of Trophic Levels
• Trophic level each step in a food chain/
“feeding” level that exists w/in an ecosystem
• 5 trophic levels typically recognized:
1. Primary producers = autotrophs/ usually
photosynthetic
2. Primary consumers = herbivores that consume
primary producers (ex: plants and algae)
• 3. Secondary consumers = carnivores that eat
herbivores
4. Tertiary consumers = carnivores that eat
other carnivores
5. Decomposers = consumers that derive
energy from detritus (organic wastes) and
dead organisms from other trophic levels
• Energy flow through an ecosystem is unidirectional (not
returned to ecosystem)
Decomposers  recycle
matter
Practice
Ecological Pyramid
• Ecological pyramid- diagram showing relationships between
organisms making up an ecosystem
• Looks at trophic efficiency percentage of production
(available energy) transferred from 1 trophic level to the next
3 Kinds of Ecological Pyramids
• 1. Pyramid of Numbers
– Numbers of organisms in each trophic level
Cont. 3 Kinds of Ecological Pyramids
2. Pyramid of Energy
o Measures the amount of energy available to higher
trophic levels
o Greatest amount of energy is present in the “producer”
level
o Only a small portion of this energy (10%) is passed on
to primary consumers, and only a small portion of the
energy (10%) in primary consumers is passed on to
secondary consumers
o Used to show the LOSS of energy (10% LAW) at each
level
o Considerable energy (in the form of heat/ 90%) is LOST
to the environment at each successive feeding level
Cont. Pyramid of Energy
Energy lost:
a. Sunlight is reflected off leaves instead of being used for
photosynthesis
b. Through respiration as heat
c. Excretion and defecation
d. Energy used for movement and transport
.01%
.1%
100%
SUNLIGHT
1%
Respiration
Heat
Waste
Assimilation
Movement
10%
Producers 100%
Cont. Pyramid of Energy
Ex:
a. Humans cellular respiration
6 O2 + glucose -------- 36 ATP (energy molecules)
(100%) --------- 55% lost as heat
b. Cycles: C, O2, N2 ------- recycled through respiration and photosynthesis
Cont. Pyramids of Trophic Levels
3. Pyramid of Biomass
o Total dry weight of ALL organisms
at EACH trophic level
o Low trophic efficiency a
decrease in available energy at
higher feeding levels
o Therefore, less organic matter/
biomass can be supported at each
higher level
a) Total mass of producers
MUST be > total mass of primary
consumers
b) Total mass of primary
consumer MUST be > total
mass of secondary consumers
Pyramid of Biomass
Ecological Pyramids
Pyramid of Numbers
Shows the relative
number of individual
organisms at each
trophic level
Energy Pyramid
Shows the relative amount
of energy available at each
trophic level/ organisms
use about 10% of this
energy for life processes
and the rest is lost as heat
Biomass Pyramid
Represents the amount of
living organic matter at each
trophic level/ typically, the
greatest biomass is at the
base of the pyramid
Competitive Relationship
• A change in the size of 1 population
affects all other organisms w/in the
ecosystem
• Predation (+/-) relationship in which 1
species kills and eats the prey
a. Predator animal that hunts, kills
and eats other animals for food
-Need to be adapted for efficient
hunting if they are to catch enough
food to survive
b. Prey organisms that predators kill
for food
- Must be well adapted to escape
their predators if enough of them are
to survive for the species to continue
Cont. Competitive Relationships
1. Niche how an organism lives/ how it does its
jobs; affects the energy flow w/in ecosystem
2. Competition when 2 species uses the same
resources/ when the resource is in limited supply
3. Character displacement response to
competition; some changes may by physical or
behavioral
4. Competitive exclusion species that is the better
competitor may drive the other out
a. No 2 species can occupy the same niche
b. Local elimination of 1 competing species
c. Species using resource more efficiently eliminates
the other
Cont. Competitive Relationships
5. Coevolution 2 species interacting w/in an
ecosystem; some work in opposition to each
other, others cooperate w/ each other
6. Coevelution “arms race”
a. Selection pressure on each other- 1 must
defend itself and the other must overcome
the defense
b. Predator counter-attack measures
Ex: stealth, camouflage, avoiding repellants
3 SPECIES OF WARBLERS &
THEIR NICHES
Figure 4-5 Three Species of Warblers and
Their Niches
Section 4-2
Cape May Warbler
Feeds at the tips of branches
near the top of the tree
Bay-Breasted Warbler
Feeds in the middle
part of the tree
Spruce tree
Yellow-Rumped Warbler
Feeds in the lower part of the tree and
at the bases of the middle branches
Camouflage/ Cryptic Coloration
Aposematic/Warning Coloration
Mimicry
Venomous Coral Snake
Red Milk Snake
• The monarch (left) and viceroy (right)
butterflies exhibiting Müllerian mimicry
Symbiosis
• 2 different species living together in some (unusual)
way
• 3 Patterns
1. Mutualism (+/+)
o Both species benefit from each other
2. Commensalism (+/0)
o 1 specie benefits while the other is neither helped
nor harmed
3. Parasitism (+/-)
o 1 specie benefits while the other is harmed
o Parasite steals nourishment from host
Cont. Symbiosis
RELATIONSHIPS:
Interactions
Competition
Parasitism
Predation
Mutualism
Commensalism
Neutral relationship
WHO WINS? (+)
WHO LOSES (-)
Effect on One
Effect on Other
Guess the relationship?
Guess the relationship?
Tick in a dog
Guess the relationship?
Barnacles on whale
The Water Cycle
Section 3-3
THE WATER CYCLE
Condensation
Precipitation
Evaporation
Transpiration
Runoff
Seepage
Root
Uptake
CARBON CYCLE
CO2 in Atmosphere
CO2 in Ocean
NITROGEN
• 79% OF ATMOSPHERIC GAS (N2) IS NITROGEN
• UNUSABLE AS GAS – PLANTS & ANIMALS MUST
HAVE IT FOR THEIR PROTEINS
• ANIMALS EXCRETE NITROGEN COMPOUNDS AS
METABOLIC WASTE (BREAKDOWN OF PROTEINS):
URIC ACID, UREA, AND AMMONIA (LISTED FROM
LEAST TO MOST TOXIC)
Nitrogen Cycle
Converts To
By (Which Bacteria)
N2
Ammonia/Protein
N2 Fixing
NH3
Nitrites NO2-
Nitrifying
NO2-
Nitrates NO3-
Nitrifying
NO3-
Nitrogen N2
Compound
Nitrogen Cycle
N2 in Atmosphere
Convert N2 to
proteins in plants
called legumes 
clover
NH3
Nitrifying bacteria:
convert NH3 to
nitrites & convert
nitrites to nitrates
NO3and NO2-
Nitrates
(Usable:
can be
absorbed
by roots)
Reduces
nitrates to
nitrogen,
restoring N2
to
atmosphere
PHOSPHOROUS CYCLE
WHICH THINGS CYCLE THROUGH THE BIOSPERE?
WHICH ONES DO SO WITH THE ASSISTANCE OF THE
ATMOSPHERE?
WATER
PHOSPHOROUS
SULFUR
CARBON
NITROGEN
OXYGEN
Concept Map
Section 5-1
POPULATION GROWTH
Population
Growth
can be
Logistic
growth
Exponential
growth
characterized by
No limits on
growth
Unlimited
resources
represented by
Constant
growth rate
J-shaped
curve
characterized by
Limits on
growth
which cause a
Falling
growth rate
represented by
S-shaped
curve
3 Factors that Affect Pop Size:
1. # of births
2. #s of deaths
3. #s of inds that enter or leave the pop
(IMMIGRATION & EMIGRATION)
POPULATION ….
• Grows when BIRTHRATE > DEATH RATE
• Stays more/ less the same when
BIRTHRATE = DEATH RATE
• Shrinks when DEATH RATE > BIRTHRATE
EXPONENTIAL GROWTH
• Occurs when inds in a
pop reproduce at a
constant rate
• Under ideal conditions
with a UNLIMITED
RESOURCE, a pop will
grow exponentially
• J-shaped curve
Figure 5-4 Logistic Growth of Yeast Population
Section 5-1
LOGISTIC GROWTH
Carrying capacity
Time (hours)
• As resources
become less
available, growth of
pop slows or stops
• CARRYING
CAPACITY # of
inds that a given
environment can
support
• S-shaped curve
LIMITING FACTORS
(CAUSES POPULATIONS TO DECREASE)
• DENSITY-INDEPENDENT: AFFECT ALL POPULATIONS
REGARDLESS OF SIZE
- UNUSUAL WEATHER, SEASONAL CYCLES, &
CERTAIN HUMAN ACTIVITIES
• DENSITY-DEPENDENT: DEPENDS ON POP SIZE
- (AFFECT LARGE & DENSE POPULATIONS, NOT
SMALL & SCATTERED POPULATIONS)
- COMPETITION, PREDATION, PREDATION,
PARASITISM, & DISEASE
A Density-Dependent Limiting Factor
A DENSITY-DEPENDENT LIMITING
FACTOR
Section 5-2
Growth of Aphids
Exponential growth
Peak population
size
Rapid decline
Steady population
size
Steady population
size
Figure 5-7 Wolf and Moose Populations
on Isle Royale
A DENSITY-DEPENDENT LIMITING
FACTOR
Section 5-2
60
2400
50
2000
40
1600
30
1200
20
800
10
400
0
1955 1960
0
1965
1970
1975
Moose
1980
Wolves
1985
1990
1995
Human Population Growth
HUMAN GROWTH POPULATION
Section 5-3
Industrial
Revolution
begins
Agriculture
begins
Plowing
and
irrigation
Bubonic
plague
Figure 5-13 Age Distribution
HUMAN POPULATION GROWTH
(AGE- STRUCTURE DIAGRAMS)
Section 5-3
U.S. Population
Males
Females
Rwandan Population
Males
Females
*** SPECIES DIVERSITYof different species in the
Speciesnumber
Diversity
biosphere
Section 6-3
***
BIODIVERSITY- sum total of the genetically based variety
of all the organisms in the biosphere
Insects
54.4%
Protists
4.2%
Other Animals
19.7%
Plants
18%
Fungi
3.4%
Bacteria
0.3%
Figure 6-16 Biological Magnification of DDT
Section 6-3
BIOLOGICAL
MAGNIFICATION/AMPLIFICATION
•CONCENTRATIONS
Magnification of
Fish-Eating
Birds
OF A HARMFUL
DDT Concentration
SUBSTANCE
10,000,000
INCREASE IN ORGS
AT HIGHER TROPHIC
LEVELS IN A FOOD
Large
1,000,000
Fish
CHAIN/ WEB
• TOP CARNIVORES
AT HIGHEST RISK
Small Fish 100,000
Zooplankton 10,000
Producers 1000
Water
1
ECOLOGICAL SUCCESION
SERIES OF PREDICTABLE CHANGES THAT OCCURS IN A
COMM OVER TIME
A. PRIMARY SUCCESION- occurs on an area of newly
exposed rock or sand or lava or any area that has not
been occupied previously by a living (biotic) community
• Pioneer species LICHEN
B. SECONDARY SUCCESION-takes place where
community has been removed
ex: in a plowed field or a clearcut forest
PRIMARY
SUCCESION
SECONDARY
SUCCESION