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ECOLOGY
The study of how organisms fit into their environment and interact with it and each
other.
CYCLING OF MATTER
Population: A group of one species
habitat: the place where a particular population lives
community: different species that live together in a habitat
The community AND all physical aspects of its habitat.
THE WEB OF LIFE
all organisms interact with the
biosphere and each other
they depend on each other for….energy and matter
ENERGY
to live,
grow,
and reproduce.
AND…MATTER
to make up their bodies
life on earth “works” because of this flow of energy and
matter
WITH FEW EXCEPTIONS, THE MAIN ENERGY
SOURCE FOR ECOSYSTEMS IS
Energy flows one way through a community
community (metabolism)
heat
Energy must continually enter the community or the community will die
Radient Energy Chemical Energy
O2 O2
H O2 H O2
CO2 CO2
Heat
MATTER* IN A COMMUNITY
*the “stuff” things are made of
matter cycles through a community
When a consumer eats a plant/animal for food --
both Energy and matter are passed to the consumer
However, unlike Energy, matter is recycled
MATTER CYCLES OF BIOSPHERE
CYCLES OF MATTER
No definite beginning or end
matter is RECYCLED – Energy is not
Matter is not used up, it is TRANSFORMED
Biogeochemical process
Pass same molecule/compound/element through biosphere over and over
CARBON CYCLE
Carbon is the main component of all living
things
Carbon is found in glucose, which is the fuel for
LIFE!
What other things do we fnd carbon in?
CARBON CYCLE
CARBON PUT INTO BIOSPHERE
Carbon dioxide (CO2)
Cellular respiration (plants and
animals)
Volcanic eruptions
Burning of fossil fuels (oils)
Methane (CH4)
Grasses and animals release
Bicarbonate ions (HCO3 -)
Found in rock and released
during erosion
CARBON TAKE OUT OF BIOSPHERE
Plants –
PHOTOSYNTHESIS…remember
– requires CO2
WHAT IS THE PATH OF A CARBON ATOM?
From apple to fossil fuel?
From YOU to banana?
From fossil fuel to YOU?
HOW IMPORTANT IS NITROGEN?
component in all amino acids
is present in the bases that make up nucleic
acids such as RNA and DNA
used in chlorophyll molecules,
Nitrogen cycle-
Atmospheric nitrogen (N2) makes up nearly 78%-80% of air.
Organisms can not use it in that form.
Lightning and bacteria convert nitrogen into usable forms.
NITROGEN CYCLE
N2 gas - atmosphere
Nitrogen-fixation by bacteria on roots of legumes
N2 NH4+ (ammonium is a
usable form of
Nitrogen for
plants)
Rhizobium
Ammonia NH4+
Nitrification by bacteria in soil
NH4+ NO3- and NO2
- (NO3- is a
usable form
of Nitrogen
for plants)
Nitrosomonas, Nitrosococcus, Nitrobacter,
Nitrococcus
Nitrates NO3- and Nitrites NO2
-
Denitrification by denitrifying bacteria in soil
NO3- and NO4
- N2 (atmosphere)
NITROGEN CYCLE
N2NH4+NO3
- and NO2-N2
The Nitrogen Cycle
THE NITROGEN CYCLE
Nitrogen
Fixation
Nitrification
Denitrification
Practice – Carbon and Nitrogen Cycling
The community AND all physical aspects of its habitat.
abiotic factors biotic factors
physical aspects
i.e. soil, water, weather
(non-living)
the organisms
(living)
THE WEB OF LIFE
all organisms interact with the
biosphere and each other
they depend on each other for….energy and matter
life on earth “works” because of this flow of energy and
matter
food chain
who eats what
who eats who
FOOD CHAIN = ONE PATH FROM A FOOD
SOURCE TO THE FINAL CONSUMER
FOOD WEB = the food chains in a particular community or ecosystem
TROPHIC LEVELS – IN FOOD WEB
1st level --
producers – make
their own food
2nd level -- primary consumers -
herbivores – eat producers
3rd level -- secondary
consumers (eat herbivores)
4th level -- carnivores (eat
carnivores)
DECOMPOSERS AKA
4th level -- carnivores (tertiary consumers)
3rd level -- carnivores (secondary consumers)
2nd level -- herbivores (primary consumer)
1st level -- producers
obtain Energy from organic wastes & dead bodies of any
trophic level
THE ENERGY PYRAMID – 10% RULE
Energy is used for growth, movement or to create body heat
Which tropic level contains the most biomass?
WHAT WOULD HAPPEN IF SLOTHS BECAME EXTINCT?
Build a Food Web
DDT
What happens in populations?
POPULATION ECOLOGY
natality (birth)
mortality (death)
immigration
emigration
Demographic events are important influences of populations
All populations undergo three
distinct phases of their life cycle:
• growth
• stability
• decline
Population growth occurs when: • available resources exceed the number of
individuals able to exploit them • Reproduction is rapid • death rates are low
Human populations are in a growth phase. Beginning in 1650, the slow population increases of our species exponentially increased. New technologies for hunting and farming have enabled this expansion. It took 1800 years to reach a total population of 1 billion, but only 130 years to reach 2 billion, and a mere 45 years to reach 4 billion.
All populations have the potential for exponential growth a.k.a j-curve
Maximum rate at
which species or
population can
increase under
ideal conditions. No limits on
resources, no competition.
Populations don’t usually grow unchecked.
growth usually has environmental
limits
(biotic and abiotic)
There are a finite amount of Energy and matter in every ecosystem
As resources become depleted,
growth slows
The environment* is the ultimate cause of population stabilization.
*biotic and abiotic
biotic and abiotic factors help establish
carrying capacity (K)*
*the maximum population an environment can sustain
LOGISTIC GROWTH CURVE Determined by availability of resources
Relationship between carrying capacity (K) and the population density over time.
There are biotic and abiotic limiting factors that determine
carrying capacity
The environment is the ultimate cause of
population stabilization.
DENSITY-INDEPENDENT FACTORS
weather
behaviors
migration
Physical characteristics
Cryptic coloration
human
activity
food supply
DENSITY-DEPENDENT FACTORS
The competitive exclusion principle: two species
that compete for the exact same resources cannot
stably coexist.
57
COMPETITIVE EXCLUSION:
THE CILIATE PARAMECIUM
How do density-dependent and independent factors determine relationships between
populations?
Each species finds its own niche
NICHE: Each species unique living arrangement in
a community
Niche includes:
The habitat Food sources
Time of day organism is most active
Think about a specific position player on a team
i.e. pitcher on a baseball team
Its niche is the role it plays in that particular ecosystem (its job)
COMPETITION
2 species use the same resource in a habitat
Competition requires: 1. Similar resource
requirements 2. Limited resources
How might a population’s niche be affected by competition?
species with similar requirements can coexist
– but they will end up
occupying smaller niches than they would if they
lived alone.
PREDATOR/PREY RELATIONSHIP
Interaction where an organism captures and
feeds on another organism
Predator
Organism that does the killing and eating
Prey
Organism that is being killed and eaten (victim)
PREDATOR/PREY RELATIONSHIP
WHAT HAPPENED TO THE FOX POPULATION AS THE RABBIT
POPULATION INCREASES? VISA VERSA?
Wolves and rabbits
Populations in a community effect each other in specific ways
-
they interact
SYMBIOSIS
Any relationship where
two species live closely
together
Symbiosis literally means
“living together”
3 main types
Mutualism
Commensalism
Parasitism
WHAT TYPE OF RELATIONSHIP IS THIS?
Who is helping who?
MUTUALISM
Both species benefit
from the relationship
A Happy couple
Flowers and bees
Flowers need bees for
pollination, bees need
flowers nectar
MUTUALISM
partners both benefit
What type of relation ship is going
on here?
•Who is helping who?
COMMENSALISM
One member of the relationship benefits
while the other is neither harmed nor helped
One-sided
Rare in nature
COMMENSALISM
one partner derives some benefit while the other is unaffected
WHAT TYPE OF INTERACTION IS GOING ON
HERE?
one partner benefits at the expense of the host
PARASITISM
planaria
tapeworm
KEEPING POPULATIONS IN CHECK
Density dependent , density independent
factors and population interactions (symbiosis)
operate in an ecosystem to keep populations
within certain boundaries.
POPULATION DENSITY
the number of individuals of a population per
unit of living space
How would you
calculate the
population density of
the three diagrams?
= total population
total area
ECOLOGICAL SUCCESSION
The numbers and types of species found in
communities change over time due to factors
such as density dependent/independent and
symbiosis
Two types
Primary
secondary
PRIMARY SUCCESSION
Occurs in an area that has never been
colonized by living organisms (i.e. lava or
glacier flow)
Bare land or rock
Pioneer species (bacteria or lichen work to create
soil)
SECONDARY SUCCESSION
Formerly inhabited area that was disturbed by
flood, fire, humans
Soil is present
Other organism rapidly repopulate due to presence
of soil
YOU TRY IT
BIOMES
Due to interactions amongst organisms,
different “Biomes” are formed
Biomes are the world's major communities,
classified according to vegetation and
organisms to that reside there
TYPES OF BIOMES – EACH HAS ITS OWN CHARACTERISTRIC
BIOMES
Biomes have changed and moved many times
during the history of life on Earth
More recently, human activities have drastically
altered these communities.
Conservation and preservation of biomes
should be a major concern to all.
Why is it important to preserve and conserve
biomes?
BIOME ACTIVITY
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