Summary
Summary Environmental Studies
This is a summary of Module 1.1 on Environmental Studies.
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Modulel.cnuironmentalstudie.su#-* Population And Community ecology
ECOLOGY is the study of the interactions of organisms with their physical and biological environment
D% Population ecology is concerned with fluctuations in the size of a
population and factors both
,
physical and social that
regulates these functions
☐¥ Community individuals live together in
populations different populations together
,
make community ,
including non-living things
in their
surroundings Ecosystem all the ecosystems on earth make up biosphere
D Biosphere is the part of the earth where
living organisms are found .
An ecosystem
De is made up of groups of different species of organisms that interact with each other and with environment
An
☐ Organisms is an individual form of life , such as a bacterium , protest , plants or animals composed of a
single cell of complex
of cells
growing and
that capable of
are
reproducing
DA community is a group of different species that inhabit and interact in particular area
A species is of closely related organisms that similar to each other and usually capable of interbreed
group
a are are
☐ very
and producing fertile offspring
D¥ An individual is a
single cell organism capable of independent existence
D¥ A population is a
group of organisms of same species that occupy the same area can breed freely with each other
D¥ Demographics of populations such as statistics ,
size , growth ,
rate . - .
What Affects the size of a Population
↳ Population size is the total number of individuals Cps parameters
Def
:
Natality -
birth Rate or production seeds
NOTE :
Def
:
Mortality -
death date
is the number of
•
Birth rate
people in year
births per 1000
Def Immigration
:
-
individuals move into a population and stay
• Death rate is the number of
Def
:
people per Year
Emigration -
individuals leave a population Do not return birth per iooo
closedpopulation.withnoimmigrationoremi~gygratioftheonlyparame.fr
s affecting any change in population number birth
, HOW IS The Growth of a Population Regulated
↳ New
Population moves into an area there lot's food , resources and no predators number of individuals will increase
Number individuals increase builds up
Environmentalre-sistan.ee Took total number of factors
-
more demands on resources made ,
that stop a population
eventually population stabilizes
•
balance reached and at a causes birth rate /immigration rate
from
decrease and death rate 1 emigration
reproducing
at it 's Max rate
number that is
carrying capacity of ecosystem increase .
De Carrying Capacity the population density that environment can support
Af Population fluctuates as it fluctuates seasonally and annually depending on resources a vial able
to Population size in an
ecosystem is self -
regulating All Negative -
feedback mechanisms
tgiwmriittiinngy Factor
D The factors that help to regulate the
growth of a
population known as limiting factors
•
Density Independent factors
↳
limits growth of a
population result natural factors and not because density or number of organisms
}*
-
Physical factions eg . rainfall , temp , humidity . . . ect
-
Catastrophic events
eg
floods fire ,
, drought, earthquakes
""" " ""° "
•
Density Dependant factors Build up
W Greater effect the
population density high organisms crowed ed they
Environmental
is ,
:
Compete ( food )
-
more resources , water , space . . .
-
More easily found predators
Resistance
-
Spread disease -
and
parasites more readily I
* stable and Unstable Populations
NOTE :
↳ Numbers
decrease its size exceeds the earring Capacity SA there is a
population
•
Deteriorating rapidly , lowing carrying capacity census every 5 years to
•
(aint support population decrease determine how many
, rapidly become extinct
People live in the
country
ttokI-s- A-
forestation.ES#nmnaa-keeadf?
1. Direct Method
2 . Mark recapture Method -
( indirect Method)
DirectMel€↳ -
Areal
* Area To
photographs
large :
whole
J0$
area to see populations
helicopters count larger
Count "
- ,
→
" "" " sins " individual " • Population '
" " ed census animals
-
for populations organisms large enough to be seen -
Humans , census forms can
Area animals be filled in
large
-
are , are not to
•
Organisms slow
moving , stationary or fixed in a Position
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