Transcript ECOLOGY - Arrowhead High School

ECOLOGY
The scientific discipline that is concerned
with the relationships between organisms
and their environments.
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How they interact with other living
things
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How they interact with the nonliving
factors of the environment
Ecology
These interactions determine the
distribution and abundance of organisms
 2 main themes in ecology:
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Where do organisms live & why?
How many organisms are present & why?
Ecological research ranges from
individuals to the entire biosphere
Ecology
Population
A group of individuals of
the same species that
lives in a particular area
& can interbreed
The black-veined white butterfly
(Aporia crataegi) mating
the lake whitefish (Coregonus clupeaformis)
http://www.maine.gov/ifw/fishing/species/identification/lakewhitefish.htm
Species
A group of organisms that can breed to
produce fully fertile offspring
A species usually consists of multiple
populations…
Great White Pelican Pelecanus onocrotalus
Community
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All the populations in an area.
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i.e., populations of all the plant species & fungi
species & bacterial species & archaea species &
protist species & animal species = all the living
parts
7-spotted ladybug
(Adephagia septempunctata)
Bean aphids
(Aphis fabae)
Red ant
(Myrmica rubra)
Broom plant
(Cytisus scoparius)
Plus...
Ecosystem
community + abiotic environment
Biosphere
The
entire
portion of
the Earth
that supports
life
biosphere
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Bio = life, sphere = sphere
Compare with the
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lithosphere (litho = stone)
hydrosphere (hydro = water)
atmosphere ( atmos = vapor)
http://www.ucar.edu/learn/1.htm
Interactions
The biosphere is the portion of earth in which all known life
forms exist. It occupies a thin layer of air (atmosphere),
water (hydrosphere), and land (lithosphere).
biosphere
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Term was first coined by geologist Eduard
Suess (1875) as A place on earth’s surface
where life dwells.
Interrelates and interacts with the other
spheres; living things have a great impact on
the other spheres
The biosphere only occupies about 0.0007% of
the volume of the planet (Margulis & Sagan,
2002)
Ecological Factors
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Abiotic factors
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The non-living parts
of the environment
sand
buildings
pollutants
water
rocks
temperature
wind
sunlight
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Biotic factors
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The living parts of
the environment
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Geese
Plankton
People
Trees
Grass
Fish
Bacteria
fungi
Biodiversity
Biological diversity (biodiversity, for short)
is all of the species found in an area AND
the interactions between those species.
Worcester City Museums
Habitat
The characteristics of the type of environment
where an organism normally lives.
(e.g. a stony stream, a deciduous temperate woodland, a mixedgrass prairie)
Biotic and abiotic
factors determine the
survival and growth of
an organism & the
productivity of the
ecosystem in which the
organism lives
This area where the
critter lives is its habitat
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Ecosystem Processes
 Energy
flow—energy moves
through the ecosystem
 Nutrient cycling—chemical
elements (matter) recycled in
the ecosystem
 IT’S
ALL ABOUT MATTER AND
ENERGY!!!
Energy Flow

1st law of thermodynamics
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Energy cannot be created or destroyed, it can
only be converted in form
2nd law of thermodynamics
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When energy changes form, some energy is
always lost in the form of heat
Energy Flow
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The SUN!!! = solar energy
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Of incoming solar radiation,
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Of the solar radiation absorbed,
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66% absorbed
34% reflected (albedo)
~22%  water cycle
Nearly all  transforms to heat & radiates
Tiny amount of solar energy goes into
photosynthesis (<0.1%)
Trophic Levels
Producers/autotrophs
 Heterotrophs
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Primary consumer/herbivore
Secondary consumer/1st level carnivore
Tertiary, quaternary, etc. consumers/carnivores
Detritivores/decomposers
Energy in Ecosystems
Energy from the Sun is the
major source of energy for
MOST of the living things we
know about
 The process of
photosynthesis traps
sunlight so it can be used by
living things
 Energy is NOT recycled
throughout the ecosystem
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Energy and organisms
Autotrophs
Plants are
considered primary
producers because
they make their
own food from
inorganic molecules
Inorganic molecules
autotrophs
complex organic molecules
Energy and organisms
Are there any non-photosynthetic
autotrophs?
 Chemosynthesis and chemosynthetic
organisms!!
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Chemosynthesis
Heterotrophs
Heterotrophs obtain
their energy from
eating/consuming
other organisms
Herbivores
Heterotrophic organisms who eat primarily
plant material
Carnivores
Heterotrophic organisms who eat other
animals
1st level carnivores
2nd level carnivores
etc.
Omnivores
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Heterotrophs, like us,
that eat both
producers (plants)
and other consumers
Detritivores
Heterotrophic organisms who ingest dead
organic matter. (e.g. earthworms,
woodlice, millipedes)
Earth worm
(Lumbricus terrestris)
Saprotrophs
Heterotrophic organisms who secrete digestive
enzymes onto dead organism matter and absorb
the digested material. (e.g. fungi, bacteria)
Chanterelle
(Cantherellus
cibarius)
Heterotroph specialists
Fruit-eating =
fructivores
 Insect-eating =
insectivores
 Detritus-eating =
detritivores
 &c.
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Feeding relationships
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Predators & prey
Herbivory
Parasite & host
Mutualism
Competition
Large blue
butterfly
(Maculinea arion)
Energy Flow in Ecosystems
 Food
chains/webs—organisms
linked by energy and nutrient
flow
 Trophic level—the feeding level
of an organism in a food
chain/web
Energy Flow Between Trophic Levels
Does 100% of energy transfer
from 1 trophic level to another?
No. Remember 2nd Law of
Thermodynamics
Energy Flow Between Trophic Levels
 Range
5-20% transference (usually
~10%)
 SO…only about 10% of the total
energy is transferred to this level to
be used by these consumers.
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= 10% RULE
 Graphical
representation of energy
transference in food web = energy
pyramid
Energy Flow Between Trophic
Levels
Why such low efficiency?
three reasons:
1) not everything gets eaten!
2) indigestible material
3) metabolic processes—energy
lost as ___________
Biogeochemical Cycles
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Elements, Chemical compounds and other
forms of matter are passed from one
organism to another and from one part of
the biosphere to another.
Pass the same molecules around again
and again within the biosphere.
Matter is always recycled!
Bioaccumulation = Biomagnification
Nutrient Cycles
What does the Law of
Conservation of Matter state?
• circular flow of chemicals =
recycling
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Water (H2O)
Carbon (C)
Nitrogen (N)
Phosphorus (P)
Sulfur (S)
Water Cycle
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Movement of water (l, s, g) through
biological, geological, and atmospheric
processes
Precipitation
Evaporation
Transpiration
Percolation
Surface waters
Groundwater
Water vapor
respiration
Sublimation
Condensation
Desublimation
Surface water flow
Ground water flow
Storage in cells
Photosynthesis
Cellular processes
&c…
Water Cycle
http://ga.water.usgs.gov
Carbon Cycle
• Carbon = building block of life
• Reservoirs = atmosphere,
ocean, organisms
• High rate of exchange in/out
reserves
• Any relation to global warming?
Carbon cycle
Nitrogen Fixation
Types
1) atmospheric fixation via
lightening or sunlight; NO3 as
precipitation (ppt)
2) biological fixation* via soil &
water bacteria (blue-green
algae); NH3; legumes & root
nodules
Water Quality & Nitrates
Soil Condition & Fertilizers
Nitrogen Cycle
Phosphorus Cycle
• Water Quality & Phosphorus
• Eutrophication: increase in
nutrient content of lakes
Phosphorus Cycle
Nutrient cycling
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Ecosystems can be sources, sinks, or
transformers of chemicals
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Source = supplier of nutrients to other habitats
Sink = “holder” of nutrients from other
habitats
Transformer = takes nutrients in one form and
gives them up as another form
Food Chain
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Energy flow can be represented by a
food chain.
Arrows show the direction the energy is flowing.
Food Chain
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Series of steps in an ecosystem in which organisms transfer
energy by eating and by being eaten.
Energy flows in one direction from sun or inorganic
compounds to autotrophs to various heterotrophs
Food Webs
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Many food chains combined together.
Ecological Pyramids
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Is a diagram that shows the relative
amounts of energy or matter contained
within each trophic level in a food chain or
food web.
3 types: biomass, energy, or numbers
What is a trophic level?
Trophic levels
First level =
Second level =
Third level =
Fourth level =
Biomass Pyramid
 The total mass of living tissue at each trophic level.
 Represents the amount of potential food available for each
trophic level in an ecosystem
Biomass Pyramid
The first level includes producers.
 Here we find the most abundant
amount of biomass.
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Energy Pyramid
About 10% of the
total energy is
transferred to this
level to be used
by these
consumers.
 This is the 10%
Rule
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10 cal
100 cal
1000 cal
10,000 calories
Ecological pyramids
Numbers pyramid
Pyramid of numbers
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The number of organisms at each trophic level.
NICHE
All the roles that an organism plays
in its environment; the way in which
an organism fits into an ecological
community or ecosystem.
Niche
The niche of a species consists of:
 What it eats
 What eats it
 Where it lives
 Shelter
 All interrelationships
 How activities affect the habitat &
benefit/harm other critters
 &c.
Niche—an example
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Sunflower
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Absorbs light, water, nutrients
Converts electromagnetic energy into chemical
energy
Produces food
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Plant tissues
Nectar
Pollen
&c.
Loosens soil w/roots
Provides shade and shelter (homes)
Niche—an example
Leafcutter ants
Niche—an example
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Leafcutter ants
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Largest herbivore—harvest huge amounts of
leaf material (15-20% of fresh vegetation)
Excavate large underground nests
Cultivate a fungus, Lepiotaceae
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Fungus fixes Nitrogen—transformed to ammonium
Extra nitrogen to surrounding soil
Escovopsis mold—potential parasite
Support Actinomycete bacteria (antibiotic)
Support fungus, black yeast (anti-fungal)
Ant eaten by various critters
 Compete with other arthropods
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Community interactions
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Competition
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Intra-species
Inter-species
Predation
 Symbiosis
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Mutualism
Commensalism
parasitism
Mutualism
• Two organisms living together and both benefiting
from each other.
Lichens are
fungus and algae
living together.
Algae produces
the food and the
fungus absorbs
the nutrients.
More Mutualistic Relationships
Bee gets food
and the flower
gets pollinated.
The ant benefits by
receiving honeydew from
the aphid, while the aphid
benefits by being
protected by the ant.
Commensalism
The relationships between two kinds of
organisms in which one benefits and the other is
not affected.
Examples:
•hummingbirds hitchhike rides with other birds
•Barnacles, ghost shrimp, &c. live on sea turtle shells
Parasitism
two organisms live together, one drawing
its nourishment at the expense of the other
The lamprey eel
gets energy from
the fish. Parasites
rarely kill the host
but will leave
wounds
What are some other
Parasites?
• Viruses
• Flukes (liver parasites)
• Tape worms (intestinal parasites)
• Fungus (athletes foot)
• Trypanasoma (malaria)
• Bacteria
Summary
Mutualism
Commensalism
parasitism
NICHE
All the roles that an organism plays
in its environment; the way in which
an organism fits into an ecological
community or ecosystem.
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
The niche as a two-dimensional shape
Species A
Niche represented
by a 2-dimensional
area
Separate niches
Species B
Species A
No overlap of
niches.
So coexistence is
possible
Overlapping niches
Species B
Species C
Interspecific
competition
occurs where the
niches overlap
Specialization avoids competition
Species C
Species B
Evolution by
natural selection
towards
separate niches
Species B’
Species C’
Specialization into two separate niches
This niche is not big enough for the
both of us!
Species A
Species D
Very heavy competition leads to
competitive exclusion
One species must go
Total exclusion
Species A has a
bigger niche it is
more generalist
Species E has a smaller
niche it is more specialist
Specialists do tend to
avoid competition
Example: Squirrels in Britain
The Red Squirrel
(Sciurus vulgaris) is
native to Britain
Its population has
declined due to:
 Competitive exclusion
 Disease
 Disappearance of hazel
coppices and mature
conifer forests in
lowland Britain
© 2008 Paul Billiet ODWS
Isle of Wight Tourist Guide
The Alien
The Grey Squirrel
(Sciurus carolinensis)
is an alien species
Introduced to Britain in
about 30 sites between
1876 and 1929
It has easily adapted to
parks and gardens
replacing the red
squirrel
© 2008 Paul Billiet ODWS
Today’s distribution
Red squirrel
© 2008 Paul Billiet ODWS
Grey squirrel