Transcript Ecology Unit - Miss Gerges

Ecology Unit—Section 1:
The Biosphere
What is ecology?
Ecology- the scientific study of
interactions between organisms
and their environments,
focusing on energy transfer.
• It is a science of relationships.
What do you mean by environment?
The word environment refers to all conditions
or factors surrounding an organism.
It is made up of two factors:
Biotic factors (living)- all living organisms
inhabiting the Earth
Abiotic factors (nonliving)- the physical or
nonliving parts of the environment (i.e.
temperature, soil, light, moisture, air
currents)
Biosphere
Biome
Ecosystem
Community
Population
Organism
Organism- any unicellular or multicellular
form exhibiting all of the characteristics
of life, an individual. (a species—a group
of similar organisms that can breed and
produce fertile offspring)
•The lowest level of organization
Population-a group of organisms of one
species living in the same place at the
same time that interbreed and compete
with each other for resources (ex:
food, mates, shelter)
Community- several interacting
populations that inhabit a common
environment and are interdependent.
Ecosystem- populations in a
community and the abiotic factors
with which they interact (ex.
marine, terrestrial)
Biome-a group of ecosystems that
share similar climates and typical
organisms.
Biosphere- our entire planet with all
its organisms and physical
environment composed of air, land,
fresh water, and salt water.
•The highest level of organization
What methods are used to study
ecology?
•Observation
•Experimentation
•Modeling
Ecological methods—modeling
Models are
created by
humans to make
predictions.
Sometimes, you must be cautious in
how a model interprets data....
Imagine graphing a
person's height as
they age. One could
predict that by the
time they were age
30, they would be
22 feet tall.
However, the model
would need to
account for the
slowing of growth
after adolescence.
Test yourself!
1. A group of animals that live in the same area and can interbreed is
called a (n) _____________________
2. The study of organisms and their interactions with the
environment is known as ___________________________
3. A large area that has a particular climate and distinct plants and
animals is called a ____________________________
4. All of the different populations living in an area (plants, rabbits,
coyotes...) is called the _________________________
5. An ecosystem includes all the living and ___________ factors in
an area.
6. The portion of the planet that can sustain life is the ________
7. Animals that can interbreed are called a(n) _______________
Feeding Relationships
• Autotrophs (producers) - capture
energy from environment and
convert it into "food"
• Heterotrophs (consumers) - must
eat things
Feeding Relationships
Primary Producersalso known as
autotrophs (algae,
certain bacteria and
plants), they trap
energy from the sun
• Bottom of the food
chain
Energy from the sun
Photosynthesis—a
process by which plants,
algae and some bacteria
capture light energy and
uses it to power chemical
reactions that converts
carbon dioxide and water
into oxygen and energyrich carbohydrates such
as sugars and starches.
This process adds oxygen
to the atmosphere and
removes carbon dioxide.
Life without light
Some organisms (such
as sulfur bacteria)
thrive in total darkness
deep beneath the
oceans around volcanic
vents. They harness
chemical energy from
inorganic molecules
such as hydrogen
sulfide. This process is
called chemosynthesis.
Feeding Relationships
Consumers- animals, fungi and many
bacteria are heterotrophs: they
ingest food containing the sun’s
energy.
• Herbivores
• Carnivores
• Scavengers
• Omnivores
• Decomposers
Feeding Relationships
ConsumerHerbivores
– Eat plants
• Primary
consumers
• Prey animals
Feeding Relationships
Consumer-Carnivores-eat meat
• Predators
– Hunt prey animals for
food.
Feeding Relationships
Consumer- Carnivores- eat meat
• Scavengers
– Feed on carrion,
dead animals
Feeding Relationships
Consumer- Omnivores -eat both plants
and animals
Feeding Relationships
Consumer- Decomposers
• Break down the
complex compounds of
dead and decaying
plants and animals into
simpler molecules that
can be reabsorbed.
Energy flow in the ecosystem
Food chain- simple model that shows
how matter and energy move
through an ecosystem. It consists
of a series of steps in which
organisms transfer energy by eating
and being eaten.
Food chain
• (just 1 path of energy)
Food web- shows all possible
feeding relationships in a
community at each trophic level
• Represents a network of
interconnected food chains
Food web • (all possible energy paths)
Test yourself!
Identify:
Primary Consumers
Secondary Consumers
Tertiary Consumers
Find the Omnivore.
Trophic Levels
• Each step or link in a food chain
is known as a trophic level.
• Trophic levels represent a feeding
step in the transfer of energy
and matter in an ecosystem.
3 types of ecological pyramids
• Pyramid of energy
• Pyramid of biomass
• Pyramid of numbers
E
N
E
R
G
Y
Pyramid of Energy
Tertiary
Consumers- top
carnivores
Secondary Consumerssmall carnivores
Primary Consumers- Herbivores
Primary ProducersAutotrophs
Pyramid of Energy
Only a small portion of the energy (about 10%) that passes
through any given trophic level is ultimately stored in the
bodies of the organisms at the next level.
Only 10% Efficiency
Pyramids of Biomass and Numbers
Biomass- the amount of organic matter
(living tissue) that make up a group of
organisms in a habitat.
• As you move up a food chain, both
available energy and biomass
decrease.
• Energy is transferred upwards but is
diminished with each transfer.
Pyramids of Biomass and Numbers
A pyramid of biomass
illustrates the relative
amount of living organic
available at each trophic
level in an ecosystem.
A pyramid of numbers
shows the relative
number of individual
organisms at each
trophic level in an
ecosystem.
Cycles of Matter—
The Biogeochemical Cycles!
Biogeochemical (biology + geology + chemical)
Matter is not used up, it is transformed, the same
atoms are passed around.
4 cycles to investigate:
1. Water cycle
2. Carbon cycle
3. Nitrogen cycle
4. Phosphorus cycle
Water cycle•Evaporation, transpiration,
condensation, precipitation
Water cycle-
Nutrient Cycles
Nutrients—chemicals that organisms
need to build tissues and carry out life
functions.
The most important nutrient cycles are:
•Carbon cycle
•Nitrogen cycle
•Phosphorus cycle
Carbon cycle-
• Carbon is a major component of all
organic compounds (molecules that
living things are made of)
• Photosynthesis and respiration cycle
carbon and oxygen through the
environment.
Photosynthesis and Respiration
In photosynthesis
carbon dioxide and
water react in the
presence of
sunlight and
produce sugar and
oxygen.
In respiration
sugar reacts with
oxygen and release
the stored energy,
carbon dioxide and
water.
Carbon cycle-
Nitrogen cycleAtmospheric 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 cycleOnly certain bacteria and industrial
technologies (making fertilizers) can
fix nitrogen.
Nitrogen fixation-convert atmospheric
nitrogen (N2) into ammonium (NH4+)
which can be used to make organic
compounds like amino acids.
N2
NH4+
Nitrogen cycleNitrogen-fixing
bacteria:
Some live in a
symbiotic
relationship with
plants of the legume
family (e.g.,
soybeans, clover,
peanuts).
Nitrogen cycle•Some nitrogen-fixing bacteria live
free in the soil.
•Nitrogen-fixing cyanobacteria are
essential to maintaining the fertility
of semi-aquatic environments like rice
paddies.
Denitrification—the process by
which soil bacteria convert
nitrates into nitrogen gas.
Lightning
Atmospheric
nitrogen
Nitrogen Cycle
Denitrification
by bacteria
Animals
Nitrogen
fixing bacteria
Decomposers
Ammonium
Nitrification
by bacteria
Plants
Nitrites
Nitrates
Phosphorus Cycle-
Toxins in food chainsWhile energy decreases as it moves up
the food chain, toxins increase in
potency.
•This is called biological magnification
Ex: DDT & Bald Eagles
“The ecological niche of an
organism depends not only on
where it lives but also on what
it does. By analogy, it may be
said that the habitat is the
organism's ‘address’, and the
niche is its ‘profession’,
biologically speaking.”
Odum - Fundamentals of Ecology
Habitat vs. Niche
Niche - the role a species plays in
a community (job)
Habitat- the place in which an
organism lives out its life
(address)
Habitat vs. Niche
A niche is determined by the
tolerance limitations of an
organism, or a limiting factor.
Limiting factor- any biotic or
abiotic factor that restricts the
existence of organisms in a
specific environment.
Habitat vs. Niche
Examples of limiting factors-
•Amount of water
•Amount of food
•Temperature
Feeding Relationships
•
There are 3 main types of feeding
relationships
1. Producer- Consumer
2. Predator- Prey
3. Parasite- Host
Symbiotic Relationships
Symbiosis- two species living together
3 Types of
symbiosis:
1. Commensalism
2. Parasitism
3. Mutualism
Symbiotic Relationships
Commensalismone species benefits
and the other is
neither harmed nor
helped
Ex. orchids on a tree
Epiphytes: A plant, such as a
tropical orchid or a bromeliad,
that grows on another plant
upon which it depends for
mechanical support but not for
nutrients. Also called
aerophyte, air plant.
Symbiotic Relationships
Commensalismone species benefits
and the other is
neither harmed nor
helped
Ex. polar bears and
cyanobacteria
Symbiotic Relationships
Parasitismone species benefits (parasite) and
the other is harmed (host)
• Parasite-Host relationship
Symbiotic Relationships
Parasitism- parasite-host
Ex. lampreys,
leeches, fleas,
ticks,tapeworm
Symbiotic Relationships
Mutualismbeneficial to
both species
Ex. cleaning birds
and cleaner
shrimp
Symbiotic Relationships
Mutualismbeneficial to both species
Ex. lichen
Type of
Species
relationship
harmed
Commensalism
Parasitism
Mutualism
= 1 species
Species
benefits
Species
neutral