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Ecology
Why study ecology?
What is ecology?
Ecologists study the biosphere.
The study of the interactions
among living things, and between
living things and their surroundings
Organisms live within the
biosphere!

The regions of the
surface and
atmosphere of the
Sooccupied
why doby
earth
living
organisms.
ecologists
study
the biosphere?
– Atmosphere = air
– Lithosphere = ground
– Hydrosphere = water
Because all organisms must
share the biosphere and
ecologists must understand
how they interact individually
and collectively
Ecologists use particular levels of
organization.
 Biome
 Ecosystem
 Community
 Population
 Organism
Biomes
A
biome is a major regional or global
community of organisms.
 Biomes
are characterized by the
climate conditions and plant
communities that thrive there.
 Tropical
rain
forest biomes
produce lush
forests.
– warm temperature
– abundant
precipitation all year
Source: World Meteorological Organization
 Grassland
biomes are where the
primary plant life is grass.
Rapid City, South Dakota
Source: National Oceanic Atmospheric Administration
• Grassland biomes are where the primary plant life is
grass.
– Temperate grasslands are dry and
warm during the summer; most
precipitation falls as snow.
– Tropical grasslands are warm through the year, with
definite dry and rainy seasons.
 Desert
biomes are
characterized by a
very arid climate.
– very low amount of
precipitation
– four types: hot, semiarid, coastal, and cold
Tucson, Arizona
Source: National Oceanic Atmospheric Administration
 Temperate
forest biomes include
deciduous forests and rain forests.
– Temperate deciduous forests have hot summers and
cold winters.
– Average precipitation
– Deciduous trees are the dominant plant species.
Burlington, Vermont
Source: National Oceanic Atmospheric Administration
• Temperate forest biomes include deciduous forests and
rain forests.
– Temperate deciduous forests have hot summers and
cold winters.
– Deciduous trees are the dominant plant
species.
– The temperate rain forests have a long
wet season and relatively dry summer.
– Ferns and moss
cover the forest floor.
 The
taiga biome is
located in cooler
northern climates.
– boreal forest
– long winters and short
summers
– small amount of
precipitation
Banff, Canada
Source: Environment Canada
 The
tundra biome
is found in the far
northern latitudes
with long winters.
– winter lasts 10 months
– limited precipitation
– permafrost
Barrow, Alaska
Source: National Oceanic Atmospheric Administration
 Minor
biomes, such as chaparral,
occur globally on a smaller scale.
Polar ice caps and mountains are
not considered biomes.
Polar ice caps have no soil, therefore no
plant community.
 The climate and organisms found on
mountains change as the elevation
changes.

Biomes are made up of smaller
units called ecosystems.

An ecosystem
includes all the
organisms as well
as the climate, soil,
water, rocks, and
other nonliving
things in a given
area


Ecosystems may
be large or small.
Ecosystems are
very complex!
– They can contain
hundreds or even
thousands of
interacting species.
Within an ecosystem, there are
living and nonliving components.
 Each
organism depends in some way
on other living and nonliving factors
in its environment
 Living
components are referred to as
Biotic factors.
 Nonliving
components are referred to
as Abiotic factors.
Biotic Factors
Abiotic Factors
Community
A
community is a group of different
species that live together in one area
Population

A population is a group of the
same species the lives in one area
Organism
 An
organism is an individual living
thing
Wrap Up: Ecologists
study levels!
Biome
Ecosystem
Ecosystem
Community
Community
Population
Population
Organism
Organism
Energy in Ecosystems
 We
talked about biotic and abiotic
factors. What else is an important
part of an ecosystem?
– Energy Flow
 Energy
is needed to fuel life
processes, such as breathing and
growing.
Where does this energy come
from?
 All
organisms must have a source of
energy in order to survive
 NOT
all organisms obtain their
energy by eating other organisms
The simplest way to look at energy
flow in an ecosystem is through a
food chain.
A
food chain is a sequence that
links species by their feeding
relationships.
– Shows connection between ONE
producer and a single chain of
consumers within an ecosystem
There are different ways organisms
obtain energy.
Producers
 Organisms
that get their energy from
nonliving resources
– They make their own food
 Producers
are also called
autotrophs
 All
ecosystems depend on producers.
Why?
 Not
all producers depend on sunlight
for their energy.
 Remember
chemosynthesis?
– Process by which organisms form
carbohydrates using chemicals, rather
than light, as an energy source
Consumers
 Organisms
that get their energy by
eating other living or once-living
resources such as plants and animals
 Consumers
are also called
heterotrophs
Types of Consumers
 Herbivores
 Carnivores
 Omnivores
 Detritivores
 Decomposers
Herbivores
 Organisms
who eat only plants (eat
only producers)
Carnivores
 Organisms
who eat only animals
Omnivores
 Organisms
animals
who eat both plants and
Detritivores
 Organisms
that eat detritus, or dead
organic matter
Decomposers
 Organisms
that break down organic
material into simpler compounds
Specialists and Generalists


Specialists are
consumers who
primarily eat one
specific organism
Example: Florida Snail Kite


Generalists are
consumers who
have a varying diet
Example: Gray Wolf
Trophic Levels
 Trophic
levels are the levels of
nourishment in a food chain.
Food Webs
 Because
generalists have a varying
diet, they may be part of several
food chains
A
food web is a model that shows the
complex network of feeding
relationships and the flow of energy
within an ecosystem
 Remember
our food web activity?
Food Web
Energy Pyramid

An energy
pyramid is a
diagram that
compares
energy used by
producers,
primary
consumers, and
other trophic
levels
Create an energy pyramid
 You
and your table mate will create an
energy pyramid using the provided
organisms.
Step 1: Color organisms
 Step 2: Cut out organisms.
 Step 3: Arrange organisms on
appropriate pyramid step
 Step 4: Calculate kilocalories per step

Cycling of Matter
in Ecosystems
 Matter
changes form but it does NOT
disappear
– What happens if you crush a rock?
 Certain
chemicals constantly cycle
through the environment
Biogeochemical Cycles
A
biogeochemical cycle is the
movement of a particular chemical
through the biological and geological,
or living and nonliving, parts of an
ecosystem
Hydrologic Cycle

precipitation
condensation
transpiration
surface
runoff
groundwater
evaporation
water
storage
in ocean

Aka the water
cycle
The circular
pathway of
water on Earth
from the
atmosphere to
the surface,
below the
ground, and
back.
Oxygen Cycle



Plants release
oxygen as a
waste product
during
photosynthesis
Humans and
other organisms
take in O2 and
expel CO2
Plants absorb
CO2 for
photosynthesis
The Carbon Cycle
carbon
dioxide
in air combustion
respiration

photosynthesis
respiration
decomposition
of organisms
fossil fuels
photosynthesis
carbon dioxide
dissolved in water
Photosynthesis
and respiration
account for
much of the
transformation
and movement
of carbon.
Nitrogen Cycle
aka Nitrogen Fixation


Certain types of
bacteria convert
gaseous nitrogen into
ammonia (NH3)
Much of the N cycle
occurs underground
where bacteria
transform nitrates
into, which are used
by plants to make
amino acids.
Create a Biogeochemical Foldable


You and your table
mate will create an
informative
biogeochemical
foldable describing
one of the four cycles
previously discussed.
You must include
descriptive sentences
and an illustration of
the cycle.
Interactions in Ecosystems
 To
understand what individuals,
populations, and communities need
to survive, ecologist study the
interactions among species and
between species and their
environment
Habitat and Niche


A habitat can be
described as all of the
biotic and abiotic
factors in an area
where an organism
lives.
WHERE an organism
lives


An ecological niche
is composed of all the
physical, chemical,
and biological factors
a species needs to
survive, stay healthy
and reproduce.
HOW an organism
lives
When two species use the same
resources in the same way, competition
occurs.
 The
principle of competitive exclusion
states that when two species are
competing for the same resources,
one species will be better suited to
the niche, and the other species will
be pushed into another niche or
become extinct.
Ecological equivalents

Ecological equivalents are two species
that occupy similar niches in
geographically separate areas.
Madagascar mantella frog
South American poison dart frog
Organisms interact as individuals
and as populations.
Competition and predation are two
important ways organisms interact.
 Competition
occurs when two
organisms fight for the same limited
resource.
Two types of competition:

Intraspecific
competition –
organisms of the
same species
compete

Interspecific
competition –
organisms of
different species
compete
 Predation
occurs when one organism
captures and eats another.
Symbiosis


Symbiosis is a close ecological
relationship between two or more
organisms of different species that
live in direct contact with one
another.
There are three major types of
symbiotic relationships.
1. Mutualism
2. Commensalism
3. Parasitism
Mutualism: both organisms benefit
Commensalism: one organism benefits,
the other is unharmed
Ø
Human Our eyelashes
are home to tiny mites
that feast on oil
secretions and dead
skin. Without harming
us, up to 20 mites may
be living in one eyelash
follicle.
Commensalism
Ø Organism is not affected
+
+
Organism benefits
Demodicids Eyelash mites
find all they need to survive
in the tiny follicles
of eyelashes. Magnified
here 225 times, these
creatures measure 0.4 mm
in length and can be seen
only with a microscope.
Parasitism: one organism benefits,
the other is harmed
+
Parasitism
+
_
Hornworm caterpillar
The host hornworm
will eventually die as
its organs are
consumed
by wasp larvae.
_
Organism is not affected
+
Braconid wasp
Braconid larvae
feed on their host
and release
themselves
shortly before
reaching
the pupae stage
of development.
Organism benefits
Each population has a
density and a
dispersion.
Population density is the number of
individuals that live in a defined area.
 Population
density is a measurement
of the number of individuals living in a
defined space.
 Scientists can calculate population
density.
Dispersion of a population shows how
individuals in a population are spaced.
 Population
dispersion refers
to how a
population is
spread in an
area.
There are three types of
dispersion.
1.
Clumped
Clumped
dispersion
2.
Uniform
Uniform
dispersion
3.
Random
Random
dispersion
Populations grow in predictable
patterns.
Changes in a population’s size are
determined by:




Immigration – movement of individuals into a
population form another population
Births – new offspring
Emigration – movement of individuals out of a
population and into another population
Deaths – death of an individual
Population growth is based on available
resources.
Exponential growth is a rapid population
increase due to an abundance of resources.
 Often referred to as the “J Curve”

 Logistic
growth is due to a
population facing limited resources.
 Often referred to as the “S Curve”
 Carrying
capacity is the maximum
number of individuals in a population
that the environment can support.
• A population crash is a dramatic decline in the size of a
population over a short period of time.
After an ecosystem experiences a devastating
catastrophe, it begins to re-grow through a process
called succession.
 Succession
is the sequence of biotic
changes the regenerate a damaged
community or create a community in
a previously uninhabited area.
 There
are two types of succession.
– Primary succession
– Secondary succession
Primary Succession


Primary succession is the establishment
and development of an ecosystem in an
area that was previously uninhabited.
The first organisms to live in a previously
uninhabited area are called pioneer
species.
Steps of primary succession:
1.
Exposed bare rock begins to crack and break into smaller
pieces (because of wind, rain and ice)
2.
Wind brings in lichen and moss spores. These organisms
grow in the cracks and break the rock even more. When
these organisms die, their remains mix with the rock to
form a thin layer of soil.
3.
With time, seeds are introduced by wind or birds. Small
flowers and hardy shrubs grow.
4.
The soil continues to grow thicker. Small trees take root,
and different animals move into the area.
5.
Different tree species take root and eventually replace the
original trees.
Secondary Succession
 Secondary
succession is the
reestablishment of a damaged
ecosystem in an area where the soil
was left intact.
 Plants and other organisms that
remain start the process of regrowth.
Time for a Scavenger Hunt!!!