Ecology Unit
Review
Ecology the study of interactions between

– organisms and organisms
– organisms and their environment
Factors that effect us:
1. Abiotic Factors
Moisture
Wind/Air currents
Light
Temperature
Soil

ABio-
stands for non
stands for living

Abiotic Factors-
nonliving factors

2. Biotic Factors: living
things
What is the organization of
Ecological Study?
Organism
Population
Community
Ecosystem
Biosphere
Levels of Organization

Individual- one
organism (living)

Ex a moose
Levels of Organization

Population- groups
of individuals that
belong to the
species and live in
the same area.
(living-living same
species)

Ex many moose
Levels of Organization

Community- groups of
different populations
(more than one
population or different
groups of species)
Ex many groups of
moose beavers, trees,
grass (all living)
Levels of Organization

Ecosystem- all
organisms in a
particular area
along with the
nonliving. (living
and nonliving)
Ex many groups of
moose beavers,
trees, grass, rocks,
water, mountains
Levels of Organization

Biome- group of
ecosystems that have
the same climate and
similar dominant
communities

Biomes: tropical rain forest,
tropical dry forest, tropical
savannah, temperate
grassland, desert, temperate
woodland and shrubland,
temperate forest,
northwestern coniferous
forest, boreal forest (taiga),
tundra, mountains and ice
caps
Levels of Organization

Biosphere- all of
the planet where
life exhists, includes
land, water, and, air

Life extends 8 km
up and 11 km
below the surface
Habitat vs. Niche


Habitat- an area where an organism lives
Niche- an organisms role in its environment
– The Long Version  full range of physical and
biological conditions in which an organism lives
and the way in which the organism uses those
conditions. Includes where in the food chain it is,
where an organism feeds

Habitat is like an address in an ecosystem
and a niche is like an occupation in an
ecosystem.
What is Succession &
what causes it?

Changes to a
community

Biotic Factor

Abiotic Factors
2 Types of succession

Primary
– From nothing
– Even the soil must be “created”

Secondary
– From soil
– Disaster can strike and make it start over
Primary Succession
Secondary Succession
Pioneer
Species

Species that colonize barren habitats

Lichens, small plants with brief
life cycles

Improve conditions for other species
who then replace them
Climax Community

Stable array of species that persists
relatively unchanged over time

Succession does not always move
predictably toward a specific climax
community; other stable communities
may persist
The trend of Succession
Pioneer stage     Climax Community
Energy Flow (Trophic
Levels)

Producers- make
their own food

Consumers- get
energy from
consuming
producers
Producers


Producers- capture
energy from
sunlight or
chemicals and use
the energy to
produce food.
Producers are
autotrophs- they
make food from
their environment
2 main types of
autotrophs

One type gets
energy from the
sun-by
photosynthesis

Another type gets
energy without
light- by
chemosynthesis
Consumers

Consumers are
heterotrophs- get
energy from other
organisms
Types of Consumers




Herbivores- eat only plants
Carnivores- eat animals
Omnivores- eat both plants and
animals
Detritivores- eat dead matter (plants
and animals)
Feeding Relationships

Energy flows through an ecosystem in one direction
from:
–
–
–
–
1. the sun or inorganic compounds
2. To autotrophs (producers)
3. To heterotrophs (consumers)
Decomposers get energy from decomposing dead
organisms
Food Chain- a series of steps in which organisms
transfer energy by eating or being eaten.
Food Web- A network of
feeding relationships.
(More realistic that a food
chain)
Food Web
They can
become
very
complex!
Trophic levels

Each step in a food
chain or a food web is
called a trophic level.
– Producers are the first
trophic level
– Consumers are the
second, third, or higher
trophic level

Each trophic level
depends on the one
below for energy
Energy Pyramid


Only part of the energy
stored in one level can
be passed to the nextmost energy is
consumed for life
processes (respiration,
movement, etc., and
heat is given off)
Only 10% of the
energy available within
one trophic level is
transferred to
organisms in the next
trophic level
Biomass Pyramid


Biomass- the total
amount of living
tissue within a
given trophic level.
A biomass pyramid
represents the
amount of potential
food available for
each trophic level in
an ecosystem.
Energy Losses

Energy transfers are never 100 percent
efficient

Some energy is lost at each step

Limits the number of trophic levels in an
ecosystem

Energy flow is a one way path! (not a cycle)
G
1-3:List at least three
things that will
happen to the energy
an animal consumes.
3
1
2
Energy
Transfer
4. What percentage the
consumed energy
can be used for
growth?
All Heat in the End

At each trophic level, the bulk of the
energy received from the previous
level is used in metabolism

This energy is released as heat energy
and lost to the ecosystem

Eventually, all energy is released as
heat
Biogeochemical Cycles
(Matter moving through the environment)

All living organisms need certain
elements/compounds for life
processes
– Ex: your cells need C,H,O,P,N & S in
order to live and reproduce (make more cells)

Cycles in nature keep these elements
“moving” from organisms to organism
(and sometimes into the atmosphere)
Biogeochemical Cycles
(Matter moving through the environment)

The flow of a nutrient from the environment to living
organisms and back to the environment

Main reservoir for the nutrient is in the environment

Transfer rates to and from reservoir are usually lower
than the rates of exchange between and among
organisms.

Matter is recycled through an ecosystem – not one way
flow
Three Categories

Hydrologic cycle
– Water

Atmospheric cycles
– Nitrogen and carbon

Sedimentary cycles
– Phosphorus and sulfur
CYCLES IN NATURE
Carbon Cycle

Carbon moves through the atmosphere
and food webs on its way to and from
the ocean, sediments, and rocks

Sediments and rocks are the main
reservoir
Carbon Cycle
diffusion
Atmosphere
Bicarbonate,
volcanic action
carbonate
Marine
food
TERRESTRIAL
webs ROCKS
Terrestrial
Rocks
photosynthesis
Land Food
Webs
Soil Water
Marine Sediments
weathering
Peat, Fossil
Fuels
Carbon in the Oceans
Most carbon in the ocean is dissolved
carbonate and bicarbonate
 Ocean currents carry dissolved carbon

Carbon in Atmosphere

Atmospheric carbon is mainly carbon
dioxide

Carbon dioxide is added to
atmosphere
– Aerobic respiration, volcanic action,
burning fossil fuels, decomposition of
organic materials

Removed by photosynthesis
Nitrogen Cycle

Nitrogen is used in amino acids and nucleic acids
(all living organism need nitrogen to make
proteins)

Main reservoir is nitrogen gas in the atmosphere

Decomposers are vital to convert ammonia into:
1. usable nitrites & nitrates for plants (nitrogen fixation)
2. nitrogen gas (denitrification = puts it back into the atmosphere)
Phosphorus Cycle

Phosphorus is part of phospholipids and all
nucleotides
– What are these?

It is the most prevalent limiting factor in
ecosystems

Main reservoir is Earth’s crust; no gaseous
phase (it never enters the atmosphere – like
carbon and nitrogen)
Phosphorus Cycle
mining
excretion
FERTILIZER
GUANO
agriculture
uptake by
autotrophs
MARINE
FOOD
WEBS
weathering
DISSOLVED
IN OCEAN
WATER
uptake by
autotrophs
weathering
DISSOLVED IN
SOILWATER,
LAKES, RIVERS
death,
decomposition
sedimentation
death,
decomposition
leaching, runoff
setting out
uplifting over
geolgic time
MARINE SEDIMENTS
ROCKS
LAND
FOOD
WEBS
Community

All the populations that live together in a
habitat

Habitat is the type of place where
individuals of a species typically live

Type of habitat shapes a community’s
structure
Biogeography
The study of the distribution of
organisms and the processes
that underlie distribution patterns
Factors that Affect
Distribution

Geologic history

Topography

Climate

Species interactions
Climate

Average weather condition in a region

Affected by:
– amount of incoming solar radiation
– prevailing winds
– elevation
Rotation and Wind
Direction

Earth rotates
faster under the
air at the equator
than it does at the
poles

Deflects patterns
at right into
rotating currents
Seasonal Variation

Northern end of Earth’s axis tilts
toward sun in June and away in
December

Difference in tilt causes differences in
sunlight intensity and day length

The greater the distance from the
equator, the more pronounced the
seasonal changes
Ocean Currents

Upper waters move in currents that distribute
nutrients and affect regional climates
Rain Shadow

Air rises on the windward side, loses
moisture before passing over the mountain
Soil Characteristics

Amount of humus

pH

Degree of aeration

Ability to hold or drain water

Mineral content
Biogeographic Realms

Six areas in which plants and
animals are somewhat similar

Maintain their identity because of
climate and physical barriers that
tend to maintain isolation between
species
Biomes

Regions of land characterized by
habitat conditions and community
structure

Distinctive biomes prevail at certain
latitudes and elevations
Biomes
Biome Chart (to fill in during presentations)
Create a Biome Table with the Following Columns:
1. Name of Biome
2. Major Location(s)
3. Avg. Temperature/climate
4. Avg. Rainfall – convert to inches
5. Major plant life
6. Major animals
7.Other – include things such as other major
identifying factors of the biome, alternate names
of the biome, limiting factors of the biome for
plants/animals, etc.
Note:
To convert rainfall from cm to in = 1cm X .39 = in
Biome
Coral
Reef
Savannah
Location
Temp.
Rainfall
Plants
Animals
Other
Chapter 4:
Population Biology
What is a population?
 What is exponential population
growth?
 What happens to a population when it
reaches its carrying capacity?

How many mice are in the following population?
Estimate!
Ready
SET
Go!
How many did you count?
What is the best way to count
them?
SAMPLING
Population Sampling

Sometimes, the entire population to be
studied is small enough for the researcher
to include the entire population in the study.
– This type of research is called a census study
because data is gathered on every member of
the population.

Usually, the population is too large for the
researcher to attempt to survey all of its
members.
– A small, but carefully chosen sample can be
used to represent the population.
– The sample reflects the characteristics of the
population from which it is drawn
Sampling Methods

There are LOTS ways to sample a
population including:
– Biased sampling, Systematic sampling, Stratified
sampling, Judgment sampling, Quota sampling,
Snowball sampling, Counting method, Hit-ormiss method, etc…

HOWEVER, the most common
methods are:
– Random and non-random sampling
– Each gives you a “best estimate” of
the population size
Population Size

Factors that affect:
– Natality
– Mortality/Fatality
– Immigration
– Emigration
Population Growth Curves

Explain what is happening to the
populations below:
Population Growth Curves

Explain what is happening to the
populations below:
Biotic Potential =
Reproductive Potential
Rate at which a population could grow
if it had unlimited resources
 If a population reached its biotic
potential it would have exponential
growth

Exponential Growth
Logistic Growth
This graph shows
a typical population
growth curve.
Under ideal
conditions a
population would
have a growth with
a slow start, then a
very fast rate of
increase and finally
the growth slows
down and stops.
Predator-Prey Relationships:
1.
2.
3.
4.
What happens if a population “booms” above carrying capacity?
Who booms first during each cycle?
Why??
Does a prey boom have to be followed by a predator boom?
Population Density

D
Limiting Factors
1. Tend to reduce ________ rate or increase ________ rate.
2. Density-Dependent Factors, depend on population size: List
• Competition for space, food, water, etc…
• Predation: Gazelle-Cheetah, Deer-Wolf, Bison-Grass?
• Parasitism and Disease
• Waste accumulation
3. Density-Independent Factors: List
• weather, seasons
• natural disasters
• human habitat disruptions
Density Dependent


Here is a dramatic
example of how
competition among
members of one
species for a finite
resource — in this
case, food — caused
a sharp drop in
population.
The graph shows a
population crash; in
this case of reindeer
on two islands in the
Bering Sea.
Inter or Intra?
Density Dependent



This graph shows the effect of interspecific competition on the population
size of two species of paramecia, Paramecium aurelia and Paramecium
caudatum.
When either species was cultured alone — with fresh food added
regularly — the population grew exponentially at first and then leveled off.
However, when the two species were cultured together, P. caudatum
proved to be the weaker competitor. After a brief phase of exponential
growth, its population began to decline and ultimately it became extinct.
The population of P. aurelia reached a plateau, but so long as P.
caudatum remained, this was below the population density it achieved
when grown alone.
Density Independent

This graph shows the
decline in the population of
one of Darwin's finches on
Daphne Major, a tiny (100acre) member of the
Galapagos Islands. The
decline (from 1400 to 200
individuals) occurred
because of a severe
drought that reduced the
quantity of seeds on which
this species feeds. The
drought ended in 1978, but
even with ample food once
again available the finch
population recovered only
slowly.
Organism Interactions
Limit Populations


Predation
Competition
– Both types


Parasitism
Crowding/stress
The Human Population
Figure 4.10 pg 104
Demography
Vocabulary
Age Structure
 Immigration
 Emigration
 Birth/Death Rate

Age Structure Pyramids

These pyramids compare the age structure of the populations of France
and India in 1984. The relative number (%) of males and females is shown
in 5-year cohorts. Almost 20% of India's population were children — 15
years or less in age — who had yet to begin reproduction. When the
members of a large cohort like this begin reproducing, they add greatly to
birth rates. In France, in contrast, each cohort is about the size of the next
until close to the top when old age begins to take its toll.
Age Structure Pyramids


These population pyramids show the baby-boom
generation in 1970 and again in 1985 (green ovals).
Profound changes (e.g. enrollments in schools and
colleges) have occurred — and continue to occur — in
U.S. society as this bulge passes into ever-older age
brackets.
Chapter 5: Diversity &
Conservation

Importance to
nature

Importance to
people
– Oxygen
– Diet
– Medicines
Loss of Diversity
Threatened
Species
 Endangered
Species
 Extinction of
Species

Endangered Species/State
•Pennsylvania -- 17 listings
•Rhode Island -- 17 listings
•South Carolina -- 42 listings
2004 Data
•South Dakota -- 12 listings
•Maine -- 15 listings
•Alabama -- 115 listings
•Tennessee -- 96 listings
•Maryland -- 26 listings
•Alaska -- 11 listings
•Massachusetts -- 24 listings •Texas -- 91 listings
•Arizona -- 60 listings
•Utah -- 47 listings
•Michigan -- 21 listings
•Arkansas -- 29 listings
•Vermont -- 8 listings
•Minnesota -- 13 listings
•California -- 300 listings
•Virginia -- 71 listings
•Mississippi -- 38 listings
•Colorado -- 33 listings
•Washington -- 41 listings
•Missouri -- 25 listings
•Connecticut -- 19 listings
•West Virginia -- 21 listings
•Montana -- 17 listings
•Delaware -- 20 listings
•Wisconsin -- 16 listings
•Nebraska -- 13 listings
•District of Columbia -- 3 listings
•Wyoming -- 18 listings
•Nevada -- 38 listings
•Florida -- 111 listings
•New Hampshire -- 12 listings •American Samoa -- 4 listings
•Georgia -- 66 listings
•Guam -- 12 listings
•New Jersey -- 23 listings
•Hawaii -- 317 listings
•New Mexico -- 42 listings •Northern Mariana Islands -- 13
•Idaho -- 25 listings
listings
•New York -- 26 listings
•Illinois -- 28 listings
•North Carolina -- 63 listings •Puerto Rico -- 75 listings
•Indiana -- 29 listings
•Virgin Islands -- 13 listings
•North Dakota -- 8 listings
•Iowa -- 14 listings
•Outlying Caribbean Islands -- 0
•Ohio -- 26 listings
•Kansas -- 15 listings
listings
•Oklahoma -- 20 listings
•Kentucky -- 47 listings
•Outlying Pacific Islands -- 0
•Oregon -- 54 listings
•Louisiana -- 26 listings
listings
Threats to Biodiversity
Habitat Loss
 Habitat Fragmentation

– Biotic Issues
– Abiotic Issues

Habitat Degradation
– Air Pollution
– Water Pollution
– Land Pollution
Exotic Species



Non-native
organisms
that “move-in”
to a particular
area
There can be
a lack of
competitors =
exponential
growth
Can take over
the niches of
native species
Example: Page 124
Conservation

Sustainable use:
– Use what you need, but don’t damage the
ecosystem
Is this a
good
example of
sustainable
use?
Conservation
Habitat Corridors
Conservation
Reintroduction Programs
 Captive Breeding

Example:
The Ginkgo Tree
would probably
be extinct if it
were not for
Chinese monks
keeping it in
captivity around
temples
Humans & The
Environment

Pest Control
– Benefits vs.
Problems
– EX: DDT
Humans & The
Environment

Ozone (O3) Depletion
– O3 forms a “good layer”
around the Earth
– CFC release is breaking
down the protective ozone
layer
– UV rays increase skin
cancers & other cell
mutations to plants &
animals!
Humans & The Environment

Acid Precipitation
– In the form of rain,
snow, dew or fog
– Created when gases
such as nitrogen
oxide (NOx) and
sulfur oxide (SOx),
generated in the
burning of fossil fuels
such as coal and oil,
react in the
atmosphere with
sunlight to produce
acids such as nitric
and sulfuric acid.
These acids dissolve
in rain to become
acid rain.
How is Acidity Measured?
When we observe acid
rain, acidity is measured
in units called pH.
 The pH scale is from 0
to 14

– pH 7 indicates neutral
– higher pH numbers =
alkalinity (base)
– smaller numbers = acid
 We’ll
do more on pH in the
“Biochemistry” chapter
Natural Acid Precipitation
CO2 combines with
water to form a
weak acid H2CO3
(carbonic acid)
 But we are adding
to the problem…

– by adding nitric and
sulfuric acids
Look at the “clean
rain” – it’s already
slightly acidic???
Effects of Acid Precipitation
• In Japan, rain which registers pH 5.6 or less is considered acid rain;
some 80-90% of the rain that falls in Japan in a year is acid rain.
• In Japan, acid rain with acidity equal to lemon juice has been
observed at Mount Tsukuba in 1984 (pH 2.5) and at Kagoshima in
1987 (pH 2.45). The problem is even more serious in North America
and Europe. In those regions, forests are withering and lakes
becoming uninhabitable to fish, and stone structures such as buildings
and bronze statues are being damaged by corrosion.
1970
1985
Humans & The
Environment

Global Warming
– “The Greenhouse Effect”
– Fossil fuels give off lots of CO2
– This builds a blanket around the earth
– It is predicted that the Earth temp. will
increase ~50C before 2050 = Ice age????
Carbon Dioxide
Increase

Carbon dioxide levels fluctuate seasonally

The average level is steadily increasing

Burning of fossil fuels & deforestation are
contributing to the increase
Greenhouse Effect

Greenhouse gases impede the escape
of heat from Earth’s surface
Global Warming

Long-term increase in the
temperature of Earth’s lower
atmosphere
Other Greenhouse
Gases

CFCs - synthetic gases used in
plastics and in refrigeration

Methane - produced by termites and
bacteria

Nitrous oxide - released by bacteria,
fertilizers, and animal wastes