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Population Ecology

The document discusses factors that affect population growth, exponential growth of populations, and the typical phases of a population growth curve. Population ecology deals with population dynamics and how populations interact with their environment. Population growth is influenced by birth and death rates as well as immigration and emigration. Exponential growth occurs when a population's per capita growth rate stays the same regardless of size, allowing populations to grow faster over time. However, resource limitations eventually slow exponential growth. A typical population growth curve includes a lag phase with slow growth, an exponential phase of rapid increase, and a stationary phase when birth and death rates stabilize.

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75 views9 pages

Population Ecology

The document discusses factors that affect population growth, exponential growth of populations, and the typical phases of a population growth curve. Population ecology deals with population dynamics and how populations interact with their environment. Population growth is influenced by birth and death rates as well as immigration and emigration. Exponential growth occurs when a population's per capita growth rate stays the same regardless of size, allowing populations to grow faster over time. However, resource limitations eventually slow exponential growth. A typical population growth curve includes a lag phase with slow growth, an exponential phase of rapid increase, and a stationary phase when birth and death rates stabilize.

Uploaded by

Trenace
Copyright
© © All Rights Reserved
We take content rights seriously. If you suspect this is your content, claim it here.
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Factors

affecting
population
POPULATION ECOLOGY growth
&
Exponential
growth
POPULATION ECOLOGY
Po p u l at i o n e c o l o g y i s a s u b - f i e l d o f e c o l o g y
t h at d e a l s w i t h t h e d y n a m i c s o f s p e c i e s
p o p u l at i o n s and h ow these p o p u l at i o n s
i n t e r a c t w i t h t h e e nv i r o n m e n t , s u ch a s b i r t h
a n d d e at h r at e s , a n d b y i m m i g r at i o n a n d
E m i g r at i o n . e m i g r at i o n
N.B
 T he number of individuals  the amount of species
living within that specific found within measur ed
location deter mines the ar ea of a r e gion in w hich
population density, or the the species g r ows is called
number of individuals the fr equency of the
divided by the size of the sample species
ar ea. Population density
can be used to describe
the location, g r owth, and
mig r ation of many
or ganisms
FACTORS AFFECTING POPULATION
GROWTH
 Factors that affects the density or frequency are :
 Birthrate _ nasality
 Death rate_ fatality
 Migration(immigration and emigration) - moving from one
population to another
 Depletion _ the effects of other organisms
(predators ,grazing , parasitism, competition)
 How often an organism reproduces.
 The number of offspring of an organism.
 The presence or absence of parental care.
 How long an organism is able to reproduce.
EXPONENTIAL POPULATION GROWTH

In exponential growth, a population's per capita (per individual)


growth rate stays the same regardless of population size,
making the population grow faster and faster as it gets larger.
In exponential growth, a population
increases by a fixed proportion in
each generation

This growth in a population is quick


but not maintained simply because VA L I D

they’re insufficient resources POINTS

ABOUT

As a population increases , it begins E X P O N EN T I A L

to experience environmental G ROW T H


resistance, because space and
resources are reduced and
competition increases for them.
PHASES OF GROWTH CURVE

 L ag phase ( sl ow)
1. perio d of lit tle to no gr owth
2. Few o f the indivi dual s ar e mature
3. Rate of repro ductio n is low
4. Or ganisms beco me famili ar with t he co ndit ions

 E xpo ne nti al gro wt h phase


1. Condi tions are ; or ganisms ar e wel l adapted to the env ir onm ent al
2. Maximum r epro ductio n rate i s r ealiz ed
3. Population grows at ev er incr easing ( ac c ele rating) rate

 Stati onar y Phase (Tr ansi tio nal, Carry ing c apaci ty)
1. Envir onmental r esi stance st eps i n as the Carr ying c apac ity is re ac he d
2. Food supplies become li mi ted
3. The number o f indi viduals ente ring the po pulatio n equals the amount l eav ing
by death or migr at ion
4. Waste pr oduct s and tox ins ac c umulate so de at h rate inc r eases
5. Bir th r ate and death rate appro ac h e quilibri um
UNDERSTANDING
A TYPICAL
POPULATION
GROWTH CURVE

LAG PHASE

EXPONENTIAL
PHASE
Click icon to add picture
STATIONARY
PHASE

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