Download Intro to Ecology

 Organization
 Response
to environment
 Homeostasis – maintaining an internal
level of stability even though external
environment is changing
 Energy use
 Growth and Development
 Reproduction
 Changes through time
The
study of interactions that
take place between organisms
and their environment.
It explains how living organisms
affect each other and the world
they live in.
Habitat is the
place an organism
lives
Niche is an
organism’s total
way of life
Abiotic
factors - the nonliving parts
of an organism’s environment.
• Examples:
air currents,
Temperature,
moisture,
light,
Soil nutrients
Biotic
factors - all the living
components of an
environment.
All organisms are affected by
both biotic and abiotic factors
in their niches
•Ecologists have organized the
interactions an organism takes part
in into different levels according to
complexity.
Organism:
An individual
living thing
Population:
A group of the
same species,
which live in the
same area
Biological
Community:
All the populations
of different
species that live in
the same place at
the same time.
Ecosystem:
Populations of
organisms that
interact with each
other in a given area
ALONG with the
abiotic components
of that area.
Biosphere:
The portion of Earth that
supports life.
•It is about 20 km (13 mi)
wide from deepest parts of
ocean to 8-10 km above
the surface
•The Earth is 600 times as
thick as the biosphere
•If Earth was an apple, the
biosphere would be the
skin
So, from smallest
to biggest:
•Organism
•Population
•Community
•Ecosystem
•Biosphere
Important words to know
 Transpiration- when plants lose water
(usually through stomata)
 Evaporation- water turns from liquid
to gas
 Condensation – Water vapor condenses
into clouds
 Precipitation – any sort of water falling
from the sky (rain, sleet , snow)
 Runoff- when water runs across land
 Carbon
dioxide is a greenhouse gas and
traps heat in the atmosphere.
 Without it and other greenhouse gases,
Earth would be a frozen world.
 But humans have burned so much fuel
that there is about 30% more carbon
dioxide in the air today than there was
about 150 years ago. The atmosphere has
not held this much carbon for at least
420,000 years according to data from ice
cores.
 The
way that carbon is fixed into an
environment – PHOTOSYNTHESIS
• From the plants, animals receive carbon (up
the food chain – discussed later)
 Carbon
is released into the
atmosphere
• Burning of fossil fuels/forest fires/etc
• Decomposing matter
• Respiration (breathing out CO2)
Even
though the air is mostly N2
gas, many organisms cannot use
it.
To be used by organisms the
nitrogen must be fixed – nitrogen
fixation
Without nitrogen, no protein or
nucleic acids!


Ways in which nitrogen is “fixed” into an
ecosystem:
• Lightning strikes
• Soil microbes (bacteria that convert nitrogen to a
usable form)
• Nodules on the roots of legumes (symbiotic
relationship)
• From the plants, animals receive nitrogen (up the
food chain – discussed later)
Ways in which nitrogen is released into
atmosphere:
• Decomposing matter
• Industrial complexes
Population Ecology
Population Ecologists study many
factors dealing with population,
the three most important are…
•Population density
•Growth rate
•Carrying capacity
Population density
measures how crowded a
population is
• The population density of
the US is about 30 people
per square kilometer (0.6
mi2)
• In Japan it is 337
people/km2
•(Data from 2003)
 Growth
rate- the amount by which a
population size changes over a given
time
 In order for a population to grow, the
birth rate (number of individuals born)
must be greater than the death rate
(number that die)
 Population size constantly changes in any
given population due to changes in
growth rates




Population grows by the
same amount at regular
intervals (week, month,
year) producing a
straight line when
graphed
Ex: population grows by
the same amount every
month (2,4,6,8,10,12)
X axis is time
Y axis is population size





The number of
individuals added to the
population gets larger
during each time interval
or generation
Ex: population may grow
at pattern such as
(1,2,4,8,16,32,64 …)
When plotted on a graph
the line looks like the
letter “J”
X axis is time
Y axis is population size
NOOO!!
 Every
ecosystem has a Carrying
capacity
 This is the maximum number of
organisms that can be supported in a
given habitat.
 The carrying capacity of a habitat is
based on limiting factors






Used to represent
carrying capacity
Typically happens when
organisms are
introduced to a new
ecosystem with few
predators
At first population will
grow slowly then rapidly
Eventually population
will reach the carry
capacity and then remain
stable at that level
X axis is time
Y axis is population size

Density-Dependent
•
Depends on
population size
•
Increases in food
competition,
disease,
predator/prey
•
Decrease in living
space and available
water

Density-Independent
•
Affects the same
percentage of a
population regardless of
its size
•
Natural disasters such
as hurricanes, fires,
earthquakes, volcanoes
or tsunami destroy a
habitat
•
Human intervention as
burning of fossil fuels
increases greenhouse
gases linked to global
warming, deforestation



Agricultural Revolution Major period of population
growth began when
humans started to cultivate
crops and domesticate
animals
Industrial Revolution –
Improved food production
and distribution
Health Care – germ theory
lead to improved hygiene,
better waste removal and
water treatment



Plague – disease that
greatly reduces the size of
population (Black Plague in
1300’s reduced the
population in England by
50%)
Famine –a severe food
shortage causing starvation
and death (Potato Famine
of 1840’s/China 1870-1890)
War – death by combat,
disease, cut off from food
supply (Germany 16181648/WWI/WWII)
Community Ecology
• Looks at the interactions of populations
within an ecosystem
Species Interactions In
Communities
1.Predator-Prey
2. Competition
3. Parasitism
4. Mutualism
5. Commensalism
The
prey is the organism that is
eaten
• The predator is the organism that
does the eating
Examples:
• Lions eating Zebras
• Snakes eating Mice
• Birds eating insects
Populations rise and fall with each other
 Competition
occurs when two or more
organisms attempt to use the same limited
resource.
• A limited resource is any resource that may
run out.
• Examples:
 Hyenas fight with lions over the same
animals
 Two cacti that are side by side compete for
water
Close
association between two
or more organisms of different
species living together
• 3 types
Parasitism
Mutualism
Commensalism
 Parasitism
is the relationship between a
parasite and a host.
 A Parasite is an organism that lives in or
on another organism and feeds on it
without immediately killing it.
• Examples: ticks, fleas, blood-sucking leaches,
and mistletoe
• The organism that the parasite feeds on is called
the Host
• The host is harmed in parasitism.
 Mutualism
is a cooperative partnership
between two species in which both
species benefit.
• An example is the bacteria in your intestines and
you.
 Billions of bacteria live in your intestines.
 They help break down food you would otherwise not
be able to digest.
 They also produce beneficial substances, such as
Vitamin K for you.
 In return, you give them a warm, dark, food-rich
environment.
 Commensalism
is a relationship in which
one species benefits from another
species and the other is neither harmed
nor helped
 This is the rarest and strangest type of
species interaction
• Example: Remoras and Sharks
 The remoras attach to the sharks and feed on scraps
left over from the sharks meals.
 The shark is neither harmed nor helped by this
relationship

Relationship
Organism #1
Organism #2

Commensalism
+
0

Mutualism
+
+

Parasitism
+
-

Predator Prey
+
-

Competition
-
-
Honey guide:
These birds will
lead people and
other mammals to
honey and after
the mammal opens
the bee hive to get
the honey, the bird
feeds on the bee
larvae
 Producers
are the autotrophs of an
environment
• Mostly by photosynthesis
 Consumers are the heterotrophs of the
environment. They can be…
• Herbivores- which eat producers
• Carnivores- which eat other consumers
• Omnivores- which eat producers and
consumers
 Primary
consumer - eats producer
 Secondary consumer - eats primary
 Tertiary consumer - eats secondary
 Detritivores - (Decomposers) - Break
down complex molecules in dead
organic matter into smaller molecules
• They are responsible for recycling many
nutrients into the soil
 Food
Chains- A single pathway of energy
relationships among organisms in an
ecosystem
 The
arrows DO NOT merely show what
gets eaten
• The purpose of the arrows is to show where the
energy is going
• Scientists refer to eating as an energy transfer,
because when one organism eats another, the
main goal is to get energy from the organism.
• SO, the arrow points at the organism that GETS
the ENERGY (the organism doing the eating)
Food
chains are a very
inaccurate depiction of feeding
relationships in an
ecosystem…Food webs are more
accurate
Food webs are interrelated food
chains of an ecosystem
Decomposers are
sometimes
shown in food
chains and food
webs
Eventually all
organisms give
their remaining
energy to
decomposers
Decomposer
Producer
– tadpole
– plankton
Consumers
- everything except
the plankton (including the
tadpole)
Each organism in a food chain or web represents a trophic level
•The trophic level is an organisms position in a sequence of
energy transfers (in a food chain or web)
•Notice Higher on the food chain means higher trophic level
Producer
Primary
Consumer
Secondary
Consumer
Tertiary
Consumer
•A top level carnivore means
that NOTHING in that
environment is able to eat it.
•Organism CAN be at more than
one level
•In this diagram, a fox eats a
snake, but it eats insects
also, it would be both a
secondary and tertiary
consumer
•In real life, many organisms
are at 2 or more levels.
 Producers
add biomass (Organic
material produced by an environment,
like glucose) to environments
 They are always at the bottom of the food
chain or web.
• So they are the origin of the energy

BUT…Producers get their energy from
the sun
• So, THE SUN IS THE ULTIMATE SOURCE OF
ENERGY IN ALMOST ALL ECOSYSTEMS
•Energy transfers within an
environment are often
shown using an Energy
Pyramid:
• Notice that energy is lost
as you move up the
pyramid
•Notice also that low trophic
levels are at the bottom
and higher levels are at the
top
 Very
little energy (10%) is transferred
when one organism eats another. Why is
this?
• Not all organisms are eaten at any given level
• Consumers cannot break down all of the organic
material in their food
• Organisms use the energy they make or
consume for themselves and do not store it,
some of the energy organisms consume is lost
as heat during digestion
This
low rate of energy transfer if
the reason that as you move up a
food chain, there are less
organisms at higher trophic
levels
• There is not enough energy to
support the organisms at
higher levels
 The
tendency of a community to retain
relatively constant conditions
 Large populations with varying genetics
tend to be most stable
• For example in a field of corn (which tends to be
genetically similar), if there is an outbreak of a
deadly corn plant virus, the community would
drastically change (most die out)
• But if the field had many other plants in
abundance, it would not change as much
The
gradual, sequential growth of a
community is called ecological
succession
This can occur in areas where no life
has been before (primary
succession)
This can also occur when there is a
disaster that completely wipes out a
community (secondary succession)
 In
both primary and secondary
succession there is a specific sequence of
growth
• The first species to grow in succession
is called the pioneer species
• Pioneer species are typically small,
grow quickly, good at growing under
harsh conditions, and good at
dispersing offspring
•No true soil is present
before Primary
Succession
•Because of this it is
slower than
secondary
•Occurs on newly
exposed or created
land-like land under
melting ice caps or
islands formed by
volcanoes
•Lichens are usually the pioneer
species
•They break down the rocks into
dirt and when they die, they
leave behind organic material,
which will be broken down by
decomposers
•This creates soil which is
basically dirt, minerals, and
organic material
•This process takes
thousands of years
 This
happens after an existing
community is disrupted by a disturbance
like a fire
 Soil is already present
 Grasses and weeds tend to be the
pioneer species
 After many years bigger plants will begin
to grow
 This process takes about 100 years
When
it reaches a climax
community
• This is simply a stable end
point
• At this point, the community
remains relatively stable
assuming there are no more
disturbances
Ecosystem Ecology
Biomes
A very large climatic region that contains a
number of smaller, but related ecosystems in it.
Found
in Northern North
America, Europe, and Asia
Has permafrost (a permanent
layer of frozen soil)
Due to the permafrost and a
short growing season, there are
few or no trees in the tundra
From right: tundra near
Churchill, Manitoba,
Canada; tundra in the
Arctic National Wildlife
Refuge, Alaska
AnaktuvukPass, Alaska
Arctic Fox
Found
near the equator
Over 200cm of rain each
year
This biome gets the most
rain and supports the
greatest variety of life
Amazon and Amazon River
Rainforest in Malaysia on the island of
Borneo
Bengal Tiger
Found
all over the world
Can be coniferous or deciduous
based on the trees that grow
there
Coniferous - Bears seeds in
cones and tend to be evergreen
Deciduous - Shed their leaves
each year
Deciduous
Coyote
CONIFEROUS
Found
south of Tundra
Also called Boreal Forest
Very cold, long winters
Animals in this biome often
migrate or hibernate during
winter
Bobcat
Lakes and other water bodies are very
common. The Helvetinjärvi National
Park, Finland, is located in the
southern boreal forest.
Taiga White Spruce taiga, Denali
Highway, Alaska Range, Alaska
American Black Bear
3
varieties: Temperate
grasslands, savanna, and
chaparral
Other names include steppes,
prairies, pampas and veldts
Characterized by grasses
dominating, few or no trees
Northern Lynx
Mongolian Gerbil
prairie
Saker Falcon
Steppe
savanna
•Receive less than 25cm of rain each year
•Can be hot or cold
•Temperatures can very greatly from day to
night (the dirt does not trap heat well,
which is what warms ecosystems at night)
Desert Kangaroo Rat
Bobcat
•Waxy cuticles
•Tiny hairs and light greens prevent
some hear absorption
•Remember, plants need CO2 to
photosynthesize. C3 plants take in
CO2 through stomata all day, which
causes water loss…
•C4 plants keep stomata half
closed
•CAM plants only take in CO2 at
night
Barrel Cactus
Palo Verde
•Animals tend to be small
•Some are able to get the water they need
from food
•Nocturnal-only out at night in hot deserts
•Burrowers
Thorny Devil
Desert Tortoise
Sonoran Desert Toad
Aphotic - no light, no photosynthesis; organisms
here typically feed on falling dead organisms from
above
 Photic - has sunlight
 Intertidal - area of the shoreline covered during
high tide and exposed during low; has organisms
that are adapted to periodic exposure to air
 Neritic - shallow water above the continental shelf;
most productive zone; upwelling carries nutrients
from deep waters making it nutrient rich.; this is
where coral reefs form in tropical areas

•Oceanic - deep parts of
ocean/open sea; fewer
species than neritic, nutrient
levels low, ½ the
photosynthesis that happens
on Earth happens in the
ocean;
•Pelagic - open ocean
•Benthic - ocean floor;
diverse life can be found
living near sea floor volcanic
vents
•Where rivers meet oceans
•Salt water mixes with fresh
•Inhabitants are well adapted to
changing temp and salt conditions
Estuary of Klamath River, Oregon
River Nith estuary, Scotland
•Eutrophic
•rich in organic matter and vegetation,
•murky and have a lot of bacteria which
eventually use all of the oxygen and that
can cause the animal life to die
•Lakes naturally become this way over time
•Oligotrohpic
•Not a lot of organic matter and vegetation
•waters are clearer
•Still supports fish and other life
 Areas
of land covered in freshwater for at
least part of the year
 Main types are marshes and swamps
 Wetlands filter pollutants from water;
they prevent flooding by taking in large
amount of water
 Las Vegas has wetlands, which is the area
that most of our rainwater drains to
(which is the reason it stays wet)
Human Impact
What are humans doing to
the ecosystems of the
world?
 ozone
layer - created a hole is this layer that
protects us from UV radiation due to
Chlorofluorocarbon (CFCs)
 greenhouse effect - this NATURAL effect
keeps the Earth warm, but due to pollution,
humans are amplifying this effect and
making it warmer than usual (overloading
the carbon cycle with too much CO2, a
greenhouse gas)
 Smog and acid precipitation are caused by
air pollution
All
of these things have had a hand
in changing ecosystems and
communities world wide
Many Ecologist study human impact
on communities by looking at:
• Biological magnification
• Keystone species
• Bioindicators
 Land
and water pollution can be a big
problem for many organisms
• Chemical that we use on farms and in our homes
can be toxic to wildlife
 Many
chemicals that enter an ecosystem
undergo biological magnification, a
process in which chemicals become
more concentrated as they move up the
food chain
These
are species that can affect
many other species in a
community
When these species become
extinct, or scarce, the entire
community changes and usually
many other species are affected
•When a species of starfish that feeds on mussels
was removed from an intertidal zone, the mussel
began to dominate and eat other species
(decreasing biodiversity)
 These
are species that are especially
sensitive to change
 Frogs are bioindicators because they live
in or around water (which is where
pollutants tend to accumulate) and they
absorb gases through their skin
 Many people believe that the world wide
decline in frog populations is an
indicator of population declines in other
species
 Means
the ability to meet human needs in such
a way that the human population can be
maintained indefinitely
• To do this, we need to make sure our resources
(like food, space and water) will always be
available
• This includes keeping the Earth healthy and
maintaining biodiversity
• Biodiversity - refers to the variety of forms of
life in an area
• If we keep doing what we are doing this is not
going to happen