Download Principles of Ecology

= is the study of organisms
interacting with other organisms
and their environment
◦It combines information from
many different sciences
 is
the portion of Earth that can
support life
◦Many different environments exist
in the biosphere
◦There are different parts that
make up any environment:
Biotic factors are all of the living
parts
Abiotic factors are all of the
nonliving parts
ex. temperature, soil, moisture,
light, wind
Organism is a living thing
2. Population is a group of organisms
of one species that live in the
same place at the same time and
interbreed
◦ Members compete for food,
water, mates, etc.
1.
Community is a collection of
interacting populations
◦ No population lives independently
of other species
4. Ecosystem is the interactions
among populations in a community
and its physical surroundings
3.
a.
b.
Terrestrial
ecosystems are
on land
Aquatic
ecosystems are
in water
= role a species plays in a community
◦The space, food, and other
conditions an organism requires
◦How a species uses and affects its
environment
= where an organism lives out its life
◦Several species may share a
similar habitat and its resources
Autotrophs (also called producers)
= organisms capable of making their
own food
1.
Heterotrophs (also called
consumers)
= organisms that obtain energy by
consuming other organisms
2.
Herbivores – “plant eaters”
◦ eat producers
a.
Carnivores – “meat eaters”
◦ eat other heterotrophs
b.
Omnivores
◦ eat both plants &
animals
d. Scavengers
◦ feed off dead or
dying organisms
e. Decomposers
◦ consume organic
waste
c.
 Energy
constantly cycles through
stable ecosystems
A food chain is a model showing how
energy moves through a portion of
an ecosystem
◦Uses arrows to indicate the
direction of energy flow
grass  rabbit  hawk
 Has
at least 3
links, but rarely
more than 5
A
portion of
energy is lost at
each link
= model that
shows all
possible feeding
relationships in
a community
◦is a network of
food chains
 Trophic
levels include groups of
organisms whose energy sources are
the same number of steps from the
sun
 Pyramids
can be used to
represent numbers and energy
conversions within an ecosystem
1.
2.
3.
The base of the
pyramid = producers
The 2nd level =
herbivores and
omnivores
The 3rd level =
carnivores and
omnivores
 Only
about 10% of the available
energy is transferred to the next
trophic level
 Symbiosis
= close, long-term
association between 2 or more
species
1. parasitism = relationship where
one organism benefits while
harming another
2.
mutualism =
relationship where
both species
benefit
3.
commensalism =
relationship where
one benefits and
the other is
unharmed
Principles of population growth = the
change in the size of a population
with time
1.
Speed of population growth
◦populations grow exponentially
◦this produces a J-shaped curve
2.
Limiting factors keep a population
from growing indefinitely
◦Density dependent factors = have
an increasing effect as a
population increases in size
◦Density independent factors =
affect all of the population
regardless of density
The carrying capacity is reached
when a particular environment
cannot support any more organisms
◦produces an S-shaped curve
3.
rapid life-history pattern
◦increase rapidly, then decline
rapidly
◦organisms have: small body size,
mature rapidly, reproduce early,
have a short life span
1.
slow life-history pattern
◦maintain pop. near the carrying
capacity
◦organisms have:
large bodies,
mature and
reproduce slowly
2.
Predation
◦many predator-prey relationships
show a cycle of pop. increases and
decreases
1.
Competition
◦small pops. have unlimited
resources
◦large pops. have to compete
fiercely for limited resources
2.
Crowding and Stress
◦in large pops. individuals exhibit
various symptoms that can lead to
a pop. decrease
3.
 CO2
molecules are being produced
by:
◦plant and animal respiration
◦decomposition
◦burning of fossil fuels
 CO2 molecules are being used during
photosynthesis by plants
Fill in the blanks with the following
choices:
 burning
 CO2 gas
 decomposition
 photosynthesis
 respiration
 waste
CO2 gas
burning
respiration
photosynthesis
decomposition
waste
 demography
= the study of
population growth characteristics
- the human population has been
increasing exponentially over the
past several hundred years
 Birth
rate is the # of individuals
born over a period of time
 Death rate is the # of individuals
that die over a period of time
 Growth rate is the difference
between the birth and death rates
 Fertility is the # of offspring a
female produces during her
reproductive years
 age
structure is studied to make
predictions of future populations
 the
age structure shows whether a
population is growing rapidly, slowly,
or not at all
 migration
= movement of
individuals into or out of a
population
 either
type of movement affects
national populations