Ecology is the study of the relationship
between living things and their environment where they live. Scientists who study ecology
are called ecologists. An ecosystem is the
environment where one or more organisms live.
Open or closed system? Nutrients are recycled, but energy leaves.
An ecosystem includes everything that
affects and interacts with the organism and
bio – biology - living
has two main parts:
(1) biotic factors: all the living things in the
environment - plants, animals, fungi, bacteria, etc.
an abiotic or a biotic?
a, an, ana = not biotic = alive
(2) abiotic factors: all the natural resources or physical
nonliving things in the environment light, air, water,
temperature, rocks,
sticks, dirt, etc.
Is it alive right now?
tree sap, pine cone, egg, seed,
snail shell, antler, tree bark?
Ecology – 2
The world environment is organized into
different levels going from small to large.
autotroph - self eating
(I) plants (producers) - get food by
photosynthesis
start - smallest
atoms
nucleus, mitochondria,
vacuole
Photosynthesis: atoms/molecules are
scrambled like eggs for food!
organelles (miniature organs)  cells
heterotroph - eat others
(II) animals (consumers) - get food
by eating
(1) individual organism
(2) population = species: able to reproduce after its own kind
(3) community = living things – many populations
and nonliving – biotic and abiotic
(4) ecosystem = living
place with a lot of living things - pond, forest, field
(5) biomes - large groups of ecosystems
that share similar climate and precipitations
(6) biosphere - all the ecosystems and
biomes in the whole planet earth
Climate = same average temperature and precipitation
Ecology – 3
A habitat is the specific
place or ecosystem where a
type of organism lives
its whole life. It
provides all the biotic
and abiotic resources
necessary for the
individual organism to survive. The size of an
organism’s habit depends on its needs. Two or more
organisms may share the same habitat if their needs
Context! See the big picture
overlap.
habitat versus ecosystem: same definition but slightly different context or details
Living place = environment = ecosystem = habitat
Habitats are specific to the individual organism population and
the individual place.
Ecosystems may include many populations – communities,
many habitats
All ecosystems are habitats, but not all habitats are
ecosystems. large – many habitats for many populations = community
ecosystem = one or more living thing
in a large area, usually several
habitats within one ecosystem
Examples of habitats:
Habitats = burrow, nest, den,
anthill, cave, dead tree, grass,
bottom of pond, cliff…etc.
Ecosystem = grassland, forest,
pond…etc.
Ecology – 4
A niche is the job or activities that an organism
does to survive in its habitat. It includes many
things such as:
the organism’s role in the food chain - is it a
producer, consumer, herbivore, omnivore...)
how it protects itself (run, fight, camouflage)
how it makes shelter (burrows, dens, nests)
how it gets food (grazes, catches, scavenges)
how it nurtures its young
social behaviors (runs in packs, sings, mates for life,
pecking orders).
Being food is the main niche for everything!
Everything is food for something else! ( except the
tertiary consumers – top of the food chain)
Ecology reduced to simplest concept:
EAT OR BE EATEN! EVERYTHING IS FOOD!
Although different organisms may live together
in the same habitat or ecosystem, different
organisms CANNOT have the same niche in that
ecosystem.
Otherwise they would
fight and compete till
one left or died.
relationship - COMPETITION
Ecology - 5
Organisms have adapted for their
niche by having specialized body parts
that help the organism do its specialized
role in the ecosystem: special beaks,
claws, fur, teeth, colorations, glands, leaves, size...
A population is a group of organisms of the same
type living together in the same place. Individuals in
the population compete with one another for food,
shelter, and mates.
one species
duck + duck + duck + duck
panda bear + panda bear + panda bear
Name some populations: (Bill Nye names over 25 in his video.)
herd
bask
colony
pride
pod
hive
peep
swarm
family
school
pack
litter
flock
gaggle
murder
rabble
trip
string
bail
culture
rafter
smack
kindle
leap
The carrying capacity of an environment is the
largest population that can be supported over a long
period of time. Populations cannot grow indefinitely
because the environment contains only so much food,
water, living space, and other natural resources. If a
natural resource (abiotic factor) becomes scarce,
populations decrease.
actual maximum number of one population in an area- can’t be larger
ex: 2000 deer in Champaign County? – any more and they would run
out of food!
sharks – run out of food by overpopulation – cannibals?
Ecology – 6
Factors that control the size of populations
are called limiting factors. (either increase or decrease)
availability of natural resources – food and water
space
disease
safety from predators
natural disasters - storms, wild fires...
relationships with other species symbiosis
Humans - hunting, urban construction,
farming, industrialization, deforestation, pollution water and air, fires... Hunting limits?
Poaching? – BAD!!!!
Extremes: poaching versus hunting ban
1 buck? + 2 does?
Overpopulation occurs when the population
exceeds the carrying capacity. It is a limiting
factor that occurs when the flow of energy
though various food webs has been unbalanced.
overpopulation can lead to extinction – run out of food!
balance (equilibrium) = more food!
The overpopulation of a species usually has
negative consequences for the environment.
Natural resources are often depleted at a rate
faster than they can be replenished. As a result,
the habitat and niche of other species changes
sometimes to the point where the population
cannot survive and becomes extinct.
Ecosystems need a little of every population, but not a lot any one – more food!
Biodiversity
Ecology - 7
Alien or exotic species are species that are
released into an environment that they had not
previously existed. They are limiting factors to
the environment because they upset the food
chains in the area and compete for natural
resources. Since exotic species are free from the
predators in their native habitat, they often
overpopulate destroying other species. Alien
species include zebra muscles, purple loosestrife
(wild flower), kudzu vines, Indian mongoose, brown
eats them, but they eat others!
tree snake. nothing
take away food and space from other populations!
A community is a group of all the populations of
different species that live in an ecosystem.
pond community = frog population + dragonfly
population + algae population + largemouth bass
population + cattail population...
all the biotic factors in an ecosystem
forest community = (maple, oak, beech) tree
populations + squirrel population + deer population + ant
population + spider population + grass population + bird
populations...
slow gradual changes in the environment
Ecology – 8
Ecological succession is the gradual process by
which a community in a particular place
develops, grows, and replaces another
community.
(1) Primary succession occurs when a
community starts to grow in an area that
previously did not contain soil and living
organisms.
Primary succession – slow 100’s to 1000’s years
Pioneer species are always producers
Primary makes dirt = dead stuff & rocks
Fires, volcanoes,
storms, rising and
dropping sea levels,
and retreating
glaciers may expose
a new area leaving
exposed rocks.
Lichen - symbiosis between:
Dirt is formed over a
long period of time
providing nutrients for
grasses and
eventually trees. As
more and more plants
start growing, animals
move in.
Steps:
(1)
(3)
(5)
(6)
The rocks chemically and
mechanically weather
providing nutrients for the
first species to live in the
new area called the pioneer
species.
algae – producer/plant (feeds the fungi)
+ fungi/decomposer (feed the plant)
Lichens are a symbiotic
combination of fungi and
algae that are able to
extract nutrients from
bear rocks, and are
often the pioneer
species for primary
succession.
exposed rock (2) pioneer species (lichens) move in
dirt is made
(4) plants and grasses move in
larger plants move in with the animals that eat them
climax community – maximum diversity
Differences between primary and secondary (at least three)?
Ecology - 9
(2) Secondary succession begins on preexisting soil with
preexisting organisms and the area gradually returns to its
previous condition.
Secondary = Fast - decades
An existing community
is disturbed by farming,
natural disasters, or an
alien species. EX. Mt. St. Helens 1980
Over time as more and
more species grow in the
new environment, a
mature ecosystem or
climax community
develops. Climax
communities have great
biodiversity so they are
more resistant to limiting
factors.
Secondary pioneers =
crabgrasses
Pioneer species such as
plant seeds or alien
species develop the soil
and populate the
environment.
more variety of food!
The term biodiversity
means variety of life. It
refers to the many different
kinds of living things found in
a particular place. The
greater number of different
things that live in an area, the
greater the biodiversity. Destroying habitats reduces
biodiversity and reduces the overall health of the
biosphere. Humans can help increase biodiversity by
reducing pollution, reducing constructions and fuel
consumption, recycling, planting trees, etc. healthy
ecosystem
more biodiversity means each species does not depend on each other as much;
if one goes extinct, others can survive!