Transcript ecology - Moeller

ECOLOGY
The study of living organisms in the
natural environment
How they interact with one another
How they interact with their nonliving environment
Levels of Organization
Organisms/Species
A single living thing that can breed/produce
fertile offspring
Population
Individuals of the same species that live in
the same area
Community
Different interacting populations that live
together in an area
Ecosystem
Collection of abiotic and biotic factors in an
environment
Biome
Biosphere
Ecosystem with same climate and similar
communities
Earth with all the ecosystems
Organisms/Species
A single living thing that can
breed/produce fertile offspring
Great White Pelican Pelecanus onocrotalus
Population
Individuals of the
same species that live
in the same area
The black-veined white butterfly
(Aporia crataegi) mating
Community
Different interacting populations that live
together in an area
7-spotted lady
bird
(Adephagia
septempunctata)
Bean aphids
(Aphis fabae)
Red ant
(Myrmica rubra)
and
Broom plant
(Cytisus
scoparius)
Ecosystem
Collection of abiotic and biotic factors
in an environment
Abiotic and Biotic Factors
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Abiotic
The non-living factors
(physical and chemical
factors) which affect
the ability of organisms
to survive and
reproduce
Examples-temperature,
oxygen, moisture
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Biotic
The living factors which
affect the ability of
organisms to survive
and reproduce
Examples-producer,
primary consumer
(grass, human, flower,
lion)
Biome

Ecosystem with same climate and similar
communities
Biosphere

Earth with all the ecosystems
Levels of Organization Once More..
Remember Our Introduction?
Which level did each direction correspond to?
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1. Students will close their eyes and imagine an animal,
anything they want as long as it lives in the wild and they
know something about it. First have them think about
their animal alone as an individual. What does it look like?
How does it move?
2. Then imagine this animal interacting with others of its
kind. Does your animal live alone or in a group?
3. Next think of other types of living things your animal
might interact with. What does it eat? What eats it? Does
it compete with other types of animals for food?
4. Next think of the non-living things that your animal
interacts with. Where does it live? Where does it find
water? What is the weather like where it lives?
5. Finally, think about your organism in relationship to the
whole planet Earth. Imagine a picture of the Earth from
space. Where on the planet does your animal live? How
does its life affect the lives around it? Hoe does its life
affect you?
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1?
INDIVIDUAL
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2?
POPULATION
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3?
COMMUNITY
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4?
ECOSYSTEM
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5?
BIOSPHERE
Populations

POPULATION ECOLOGY is the study of
populations in relation to environment.

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Including environmental influences on
population density and distribution, age
structure, and variations in population size
Population Density – number of
individuals in a specified area of a habitat.
Dispersion

Describes how individuals in a population
are distributed

Dispersion patterns themselves are affected by
the distribution of resources (including sunlight,
nutrients, prey species, etc.) in the environment
Types of dispersion patterns
1. Clumped - individuals aggregate in
patches; may be influenced by resource
availability & behavior
Types of dispersion patterns
2. Uniform - individuals are evenly
distributed; may be influenced by social
interactions such as territoriality
Types of dispersion patterns

3. Random - the position of each individual
is independent of other individuals
What can cause a
change in population?
births/natality
 deaths/mortality
 immigration
 emigration

Population Growth Patterns

Exponential
growth - the
individuals are not
limited by food,
disease, predation
or competition.
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Results in J-shaped
curve.
This growth is not
sustainable – short
lived in nature.
Population Growth Patterns
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Logistic growth –
the individuals are
limited by
environmental
factors.
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Carrying Capacity: the
maximum size of a
population that an
environment can sustain
indefinitely
Results in S-shaped
curve.
Populations tend to
attain an equilibrium
in size which is
determined by the
available resources.
Limiting Factors
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Limiting factors-Things that prevent a
population from reaching its biotic
potential

Density-Independent Limiting Factors:
affects all populations regardless of density
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Ex: weather, natural disasters, human activity
Happen regardless of population size
Limiting Factors
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Density-Dependent Limiting Factors:
limits when population density reaches
carrying capacity
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disease, competition, predation, resources
availability, parasitism
As more organisms crowd together, these
factors cause more damage.
Community Ecology

COMMUNITY ECOLOGY – concerned with
community structure & population
interaction
Symbiosis
Symbiosis-two species live in a close, long
term relationship
Types of Symbiosis: Mutualism

Both species benefit
from the symbiotic
relationship

Ex: nitrogen-fixing
bacteria on legumes,
bees and flowers,
Types of Symbiosis: Commensalism
One organism is
benefited and the other
is unharmed
Ex: barnacles on
whales, orchids on
tropical trees
Types of Symbiosis: Parasitism
One organism
benefits, other is
harmed
Ex: athlete's foot
fungus on
humans,
tapeworm and
heartworm in dogs
Habitat
The characteristics of the type of environment
where an organism normally lives.
(e.g. a stoney stream, a deciduous temperate
woodland)
The place of an organism in its
environment
Niche-
an organism’s use of the
biotic and abiotic
resources in its
ecosystem
• Some say an
organisms “job” in
the ecosystem
Species A
Niche represented
by a 2-dimensional
area
Separate niches
Species B
Species A
No overlap of
niches.
So coexistence is
possible
What happens if two niches
overlap?!?!
Overlapping niches
Species B
Species C
Interspecific
competition
occurs where the
niches overlap
The Competitive Exclusion Principle
G.F. Gause (1934)
If two species, with the same niche, coexist in the same
ecosystem, then one will be excluded from the community due
to intense competition
Which means….two species competing for
the same limiting resources cannot coexist
in the same place
Competition
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Competition – organisms attempt to use
an ecological resource in the same
habitat
*The more similar
the requirements
of the organisms
involved, the
more intense
the competition.
Predator/Prey

Predation – the act of one organism
feeding on another

How to increase survival chance?

camouflage, warning coloration and mimicry
Succession

Succession-community changes over time

Two types:
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Primary succession
Secondary succession
Primary Succession

Primary succession-occurs in area where
no soil exists; starts with a pioneer
species
Secondary Succession
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Secondary succession-begins in an area
where soil remains after a disturbance
Energy and organisms
Autotrophs
(producers)–
make their own
food
 photosynthetic – use sunlight
 chemosynthetic – use inorganic
materials
Heterotrophs
(consumers) –
rely on others for
food
Types of Heterotrophs:
Herbivore
Only eats plants
Carnivore
Only eats animals
Types of Heterotrophs:
Omnivore
Eats plants & animals
Decomposers
Cause decay
Types of Heterotrophs:
Detritivores
Organisms who ingest dead organic
matter. (e.g. earthworms, woodlice,
millipedes)
Earth worm
(Lumbricus terrestris)
Word Parts
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Autotroph
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auto=self
troph=feeding
Heterotroph
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Hetero-different
troph-=feeding
Trophic Levels
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Remember what
troph meant?!
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FEEDING!
So…
A trophic level is
a feeding level of
one or more
populations.
Trophic levels make
up……FOOD WEBS!
Food Web
A food web is a
branching food
chain with
complex
trophic
interactions
Food Web
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1st Trophic
Level (primary
producers)-use
sunlight directly
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2nd Trophic
Level (primary
consumer)herbivores that feed
directly on plants
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3rd Trophic Levels are
carnivores (secondary
consumer) feeding on
each other
Food Chain

A food chain
represents
passage of
energy
through
populations in
a community.
Food Chain vs. Food Web
Food Pyramid
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A food pyramid
shows the
energy
content that is
passed to each
successive
trophic level in
a food web.
What are all those
arrows actually showing?
 ENERGY
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FLOW!
Notice the arrows
points towards
the individual
that is receiving
the energy!!!!
 (The
one doing
the eating)
Energy Flow
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ECOSYSTEMS – ENERGY FLOWS IN ONE
DIRECTION THROUGH AN ECOSYSTEM
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First law of thermodynamics: energy can neither
be created nor destroyed; it can only be changed
from one form of energy to another.
Energy Flow

Second law of
thermodynamics:
when energy is
transformed from
one form to
another, there is
always some loss
of energy from
the system.
Energy Transfer
Energy Transfer – ONLY 10% of energy
is transferred up the trophic levels
 remaining energy is lost as heat
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Something to
think about:
Why are there
more herbivores
than carnivores?
Biomass
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Biomass – total amount of living tissue in
each trophic level; lower level has
greatest
Cycles of Matter
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To have a self-sustaining
ecosystem, materials must be
cycled among the organisms and
the abiotic environment to be
reused by different living
organisms.
Three main elements must
move through an ecosystem:
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Water
Carbon
Nitrogen
Water Cycle
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This cycle is made
up of a few main
parts:
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evaporation (and
transpiration)
condensation
precipitation
collection
Carbon Cycle
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1. Plant leaves take carbon dioxide from air
2. Plants store carbon in carbohydrates or starches
(photosynthesis)
3. Plants & animals release carbon dioxide back into the
air (cellular respiration)
4. Decomposers
return carbon to
environment
(decomposition)
Nitrogen Cycle
N2 Fixation –
bacteria/lightning/
volcanic action convert
N2 gas into NH3 then
convert it into
nitrites/nitrates into soil
for plants to use
Denitrification –
bacteria (decomposers)
convert nitrates/nitrates
from soil into N2 gas
releasing into
atmosphere
Biomes
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Biome-Ecosystem with same climate and
similar communities

CLIMATE – is primary factor that determines
communities and distinction between biomes
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Average yearly conditions of temperature and
precipitation in a particular region
Biomes
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Terrestrial
Biomes:
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Temperate grassland (prairie)
Tundra
Taiga (coniferous forest)
Deserts
Temperate Deciduous Forest
Savanna
Tropical Rain Forest
Polar
Temperate Grassland
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Grasses w/ fertile
soil
Tundra
Cold and Dry
 Permafrost - layer
of permanently
frozen soil
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Taiga
In Northern
areas/on mountains
 Evergreen trees
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Desert
Hot in day, cold at
night
 Low amounts of
rainfall
 Plant species store
water
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Temperate Deciduous Forest
Deciduous trees
 Distinctive seasons
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Savanna
Dry, short periods
of heavy rain
 Plants – grasses
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Tropical Rainforest
Hot and high levels
of rain
 Great diversity of
plants and animals
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Polar
Very little plant
growth
 Bitterly cold
temperatures
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Aquatic Biomes
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Freshwater lakes, ponds,
rivers, streams
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Marine – oceans
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Photic zone receives light
Aphotic zone - not
enough light for
photosynthesis
Environmental Issues and
Human Influences
What about excessive use of
resources?
There are 2 types—determined by how long it
takes to renew

Nonrenewable
Resources
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cannot be replenished
by nature within our
lifetimes - are limited
in supply - fossil fuels,
metals, other minerals
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Renewable
Resources
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energy sources that do
not consume fuel
reused and recycled
materials – not
unlimited if abused
Sustainable Use – using natural resources at
a rate that does not deplete them
Resources aren’t the only things
getting abused
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Land abuse causes
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soil erosion
desertification – in dry climates, combination
of farming, overgrazing and drought has
turned productive areas into deserts
deforestation
Air and Water Pollution
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Acid Rain – burning of fossil fuels release
N2 & S which combine with water vapor to
form nitric and sulfuric acid
Biological Magnification
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Biological Magnification – concentration
of harmful substances increase in
organisms as chemicals travel in the food
web
Biological magnification can
cause….
Endangered species – endemic species
that is highly vulnerable to extinction
 Habitat loss – physical reduction in
suitable places to live
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Loss of biodiversityvariations of life at all
levels of biological
organization
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Ozone Depletion
Layer of ozone (O3) is normally present in
Earth’s upper atmosphere
 Prevents much of UV light emitted by sun
from reaching Earth’s surface
 Chlorofluorocarbons (CFCs)–
in polar atmosphere, CFCs
act as catalyst that enable
UV light to break apart
ozone materials

Why is this bad?

This harmful UV radiation can now possibly
affect humans, animals, and plants
Greenhouse Effect

Heat is retained by the layer of gases
(CO2, CH4, etc) forming the atmosphere
Global Warming

Increase in average temperature of
biosphere
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Over past 120 years, global temperature has
risen .5o C
Global Warming
CAUSES – human activities have caused
global warming by adding CO2 and other
greenhouse gases to the atmosphere
 RESULT– atmospheric greenhouse gases
retain more heat
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