Download Unit 2: Ecology

Unit 2: Ecology
THE BIOSPHERE
What is Ecology?
 Ecology is the scientific study of interactions among
organisms and between organisms and their
environment, or surroundings
 Can you think of interactions between organisms in
the environment?
The Biosphere
 The Biosphere contains the combined portions of
the planet in which all of life exists, including land,
water, and air or the atmosphere
 Interactions within the biosphere create a web of
interdependence between organisms and the
environment in which they live.
Levels of Organization
 To understand relationships within the biosphere,
ecologists ask questions about events and
organisms that range in complexity from a single
individual to the entire biosphere
Levels of Organization
 An individual is the single organism that makes up a




population (a group of the same animal, plant, etc. like a
species)
A community is multiple populations (multiple species)
like deer, squirrels, and bears that may all live in the same
area
All of the organisms and their nonliving, physical
environments make up an ecosystem
Multiple ecosystems come together to make up the
biome, which has similar environments (like water, air,
woods, etc.)
The highest level (largest) is the entire biosphere which
is all the biomes on the planet
So, How do scientists study these groups???
 Scientists gather information using three basic
approaches
Observing – what species live here?, how many
animals in the herd?
2. Experimenting – use artificial environments to test
hypotheses
3. Modeling – make models to help predict and
understand relationships of larger groups that
would otherwise be difficult to observe
1.
Checkpoint 
1.
What are the six different levels of organization
that ecologists study?
2. What are the three basic methods of ecological
research?
Checkpoint 
3. What are three ways in which you interact every
day with each of the three parts of the biosphere
– land, water, and air??
Energy Flow
 Where do we get all of our energy from?
 Can we use the sunlight?? How do WE get our
energy?
Producers
 Sunlight is the main energy source for life here on
Earth
 Some organisms don’t use the sunlight… they can use the
energy stored in inorganic compounds – make their
energy using chemical reactions rather than the sun.
A.K.A. Producers
 Organisms that can make their own energy (from
sunlight OR from chemical means) are known as
AUTOTROPHS (auto- = self & -troph = food)
 These organisms that can produce their own food are
also called producers.
Where does the energy come from?
 Like we said, most autotrophs obtain their energy
from the sun
 They harness this energy in a process known as
________________.
Where does the energy come from?
 Like we said, most autotrophs obtain their energy
from the sun
 They harness this energy in a process known as
Photosynthesis
 Plants use the energy from the sunlight to convert
Carbon Dioxide and Water to Carbohydrates
(sugars) and Oxygen
Photosynthesis
Carbon dioxide reacts water in the presence of light
energy to form carbohydrates and oxygen gas
--or-Light Energy
CO2 + H2O ------------> carbohydrates + O2
Chemosynthesis
 What if we don’t have light? Does this mean we
don’t have life?
 Some organisms can make their own energy
(autotrophs) without light
 They do this using chemosynthesis or making
energy using chemical changes without light
What do other animals do??
Consumers
 If you cannot make your own energy like the
autotrophs (or producers) than you may need to EAT
THESE ORGANISMS
 Organisms that cannot make their own and must eat
other organisms are known as consumers (they
consume other animals)
 These are also known as heterotrophs
Feeding Relationships
 We are all tied together and all rely on each other
 The plants need animals to exhale carbon dioxide so
that they may use the sunlight and create their own
sugars and foods.
 This tight interdependence is known as a Food Web
or Food Chain
Relationships
 Energy flows through an ecosystem in one direction,
from the sun or inorganic compounds to autotrophs
(producers) and then to various heterotrophs
(consumers)
 The energy stored by producers can be passed
through an ecosystem …….
Wait…. What is an ecosystem??
Relationships
 Energy flows through an ecosystem in one direction,
from the sun or inorganic compounds to autotrophs
(producers) and then to various heterotrophs
(consumers)
 The energy stored by producers can be passed
through an ecosystem along a food chain
Lets make our own!!
 Create a food chain with at least 4 organisms that
rely on one another.
Maybe…..
Grass seeds --- mouse --- snake --- hawk
--or-Vegetation --- caterpillar --- bird --- coyote
Relationships
 When the feeding relationships among the various
organisms in an ecosystem form a network of
complex interactions, ecologists describe these
relationships as a food web
 These tie in many organisms within an ecosystem
who all rely on multiple food sources and play a large
role on the stability of the ecosystem
Where does the energy go!?!?!
 These “steps” or “levels” on a food chain or food web
are known as Trophic Levels
 As you go from level to level there are fewer
organisms
 Many, many producers on the bottom and only a few
or less consumers all the way on the top
 Why do you think this is so?
Everyone needs energy!!
 Each step requires energy for themselves
 Only about 10% is transferred from level to level…
so the hawk eating the rabbit only gains about 10% of
the rabbit’s energy
 The other 90% was used by the rabbit to live, stay
warm, grow, reproduce, etc.
Ecological Pyramids
 An ecological pyramid is a diagram that shows
the relative amounts of energy or matter contained at
each trophic level in a food chain or food web
 WHAT DO YOU THINK IS ON TOP?? BOTTOM??
 Grass, plants, berries, etc. are at the bottom… and
are the most abundant
 Top predators (wolves, coyotes, mountain lions) are
at the top and are the least abundant (fewest)
Only 10%???
 Because only 10% is transferred from one trophic
level to the next, there NEEDS to be MUCH more to
feed the level above them
 Meaning, there needs to be a lot more grass than
deer to feed them.
 There needs to be a lot more deer than coyotes to
feed them too 
Let’s see where we are at…
In your notes, ON A SEPARATE SHEET OF PAPER TO
TURN IN, answer the following questions with a partner
1.
2.
3.
4.
5.
What are the two main forms of energy that power
living systems?
Explain the relationships in the food chain between a
herbivore, a carnivore, and an omnivore
What proportion of energy is transferred from one
trophic level to the next in an ecosystem?
Why is the amount of energy transferred from one level
to the next so low?
What are the eight characteristics all living things
share?
Cycles of Matter
 What is matter?
 Unlike the one-way flow of energy, matter is
recycled within and between ecosystems

What does it mean to “recycle” something?
Recycling in an Ecosystem
 We call this recycling process biogeochemical
cycles
 Bio – meaning life
 Geo – meaning earth matter
 Chemical – meaning the chemicals and compounds
 An ecosystem recycles these materials – they never
increase or decrease in amounts… just go around and
around forever
The Water Cycle
 The water moves
between the ocean,
atmosphere, and the
land
 Water enters the
atmosphere by
evaporation
 Water can also enter the
atmosphere by leaving
plants in a process called
transpiration
The Water Cycle
 Water can come back down to the land and oceans
by precipitation (raining, snowing, etc.)
 How are evaporation and transpiration related??
Nutrient Cycles
 In addition to WATER, ecosystems must recycle
nutrients also!!
 There are three different types of nutrients that
MUST be recycled in an ecosystem!!
1. The Carbon Cycle
2. The Nitrogen Cycle
3. The Phosphorus Cycle
#1  The Carbon Cycle
 Carbon can be exchanged and recycled through an
ecosystem through a variety of ways




Photosynthesis, respiration, decomposition use and release
carbon and oxygen
Geochemical cycles like erosion and volcanoes release carbon
dioxide into the atmosphere and oceans
Dead animals and organic matter convert to fossil fuels –
burning these materials releases the carbon
Mining, cutting and burning forests, and burning fossil fuels
release carbon dioxide into the atmosphere
#2  The Nitrogen Cycle
 All organisms require nitrogen to make amino acids,
which are used to make proteins
 Nitrogen can be shuffled through an ecosystem in
many different forms:


Ammonia (NH3)
Nitrate (NO3-)
nitrogen gas (N2)
nitrite (NO2-)
The Nitrogen Cycle
 Some bacteria can convert nitrogen gas into
ammonia in a process known as nitrogen fixation
 Some soil bacteria convert nitrates into nitrogen gas
in a process known as denitrification
 These bacterial help to recycle the nitrogen round
and round and allow it to re-enter the atmosphere
and environment
#3  The Phosphorus Cycle
 Phosphorus is needed to make DNA and RNA,
making it very important
 Phosphorus is the ONLY one (out of water, carbon,
and nitrogen) that DOES NOT ENTER THE
ATMOSPHERE
 What does that mean??
The Phosphorus Cycle
 Phosphorus remains mostly on land in rock and soil
minerals and in ocean sediment
 The rocks and soil are gradually eroded and broken
down which releases the phosphorus back into the
environment
 Where is most of the phosphorus stored in the
biosphere???
Nutrient Limitation
 An ecosystem will always grow when there are
available resources (food, water, NUTRIENTS)
 When the nutrients run out _______________.
 When an ecosystem is limited by a single nutrient
that is scarce or cycles very slowly, this substance is
called a limiting nutrient
Fertilizers
 This is why farmers put fertilizer on their corps to
make them grow better
 Fertilizers are composed of nitrogen, phosphorous,
and potassium
 They add this to their crops and then WATER
THEM!!
Are Fertilizers good or bad??
 If these fertilizers runoff into local water sources, an
algal bloom may occur
 An
ALGAL BLOOM is an immediate
increase in the amount of algae and other
producers
Where are we??
WRITE DOWN and answer these questions IN YOUR
NOTES IN COMPLETE SENTENCES!!
1. How does the way matter flows through
an ecosystem differ from the way the
energy flows?
2. Why do living organisms need
nutrients?
3. Explain how a nutrient can be a
limiting factor in an ecosystem.
What Shapes an Ecosystem??
 Ecosystems are influenced by both living and
nonliving factors
 Biotic factors are the living factors such as birds,
trees, mushrooms, bacteria, …
 Abiotic factors are the nonliving factors such as
temperature, precipitation, humidity, water
(streams, ponds, lakes, etc.), rocks, …
 Together, biotic
and abiotic factors
determine the
survival and
growth of an
organism and the
productivity of the
ecosystem in which
the organism lives
The Niche
 If an organism’s habitat is its address… then its
niche is its occupation
 A niche is the full range of physical and biological
conditions in which an organism lives and the way in
which the organism uses those conditions
NICHE
 An organisms niche can be
6.
Its place on the food chain/web
Temperature range
Food requirements
How it obtains food
What eats it
Physical conditions
7.
When and how it reproduces
1.
2.
3.
4.
5.
Community Interactions
 Community interactions, such as competition,
predations, and carious forms of symbiosis, can
powerfully affect an ecosystem
 So, its all about HOW they interact with each other
Competition
 Competition is when two organisms compete for a
desired resource.
 This could be food, water, territory, or even mating
rights,
 Competition usually ends with one species winning
and living happy and the other losing and possibly
dying out (failing to survive)… Why??
Predation
 An interaction in which one organism captures and
feeds on another organism is call predation
 What types of defenses do some prey use to not be
captured and eaten by a predator?
Symbiosis
 Any relationship in which two species live closely
together is call symbiosis

Literally means “living together”
 There are 3 types of relationships in nature:
1.
Mutualism
2.
Commensalism
3.
Parasitism
1. Mutualism
 Both species benefit
 Like:
 Apple trees and bees
 Flowers and insects
 Birds eating the ticks off bigger animals
2. Commensalism
 In commensalism, one animal benefits and the
other one is neither helped or harmed
 Like barnacles on a whale… they don’t help or harm
the whale but get a free ride and constant motion so
they can filter the moving water and eat
3. Parasitism
 In parasitism, one organism lives on or inside
another organism and harms it.
 So, one benefits and the other is harmed or
weakened… but not usually killed.. Why not??
Ecological Succession
 Ecosystems are constantly changing in response to
natural and human disturbances.
 As an ecosystem changes, older inhabitants
gradually die out and new organisms move in, which
causes further changes
Primary Succession
 Succession that occurs on land where no soil exists is
called primary succession
 For example, after a volcano
 The first new species
are known as the
Pioneer Species
– “first ones”
Secondary Succession
 A disturbance of some kind cahnges the exsting
community without removing the soil is known as
secondary succession
 This could be a wildfire
Lastly, Marine Succession
 A disturbance can take place in any ecosystem.. Even
a marine ecosystem
 When a whale dies and lands on the bottom of the
ocean, this is a big disturbance
 The organism all work together to clean it up and put
it back to normal
What do we know??
 What is the difference between biotic and abiotic
factors?
 Name three types of community interactions that can
affect an ecosystem
 What is the difference
between primary
succession and secondary
succession?