Population (Size & Growth) Video Lecture | Business Economics for CA Foundation

welcome back guys in this video tutorial
we'll be talking about the ring the
population size and their growth and how
to regulate the population size now for
for the understanding of population
growth what we need to know is that the
population growth is denoted with
capital G and this capital G stay
multiplied by capital n now here capital
G is a growth rate population growth
rate here capital G equals to small R
multiplied by capital n now here capital
e is the number of individuals in the
population okay and small R is the very
interesting factor here because R is
denoted as intrinsic growth rate
intrinsic growth rate intrinsic growth
rate means R is the rate of R is a rate
where the individuals is growing that
means say this R depends on two
important things one is the birth and
death birth rate and death rate okay
these two things control the intrinsic
growth rate but if birth rate is higher
than death rate right if birth rate is
higher than death rate that means people
are burning more less people are dying
so the population will grow but if the
birth rate is less than death rate that
means more people are dying less people
are born so as a result the growth
intrinsic growth let will be in a -
value right it will be not - in the 0
less than 0 so in that case it will it
will be the population will not grow it
will it will slowly decline the
population growth will be less so there
are the thing depends on R so if R
equals to 0 the intrinsic growth rate 0
means the death rate the birth rate
equals to the death rate right that
means the number of individuals are
dying and the number of individuals
birth they are both equals right so as a
result epi
zero so the intrinsic rate will also be
zero and the population here we are will
be in the constant growth rate right but
if the value for R if the value for R is
more than 0 that means the population is
growing if it is less than zero it is
not growing it is declining okay
so this is the idea about the population
size population growth now about the
population size population size also
depends on the huge birth rate if the
birth rate is higher and the death rate
is lower so the population will also
grow that means the population size will
also increase it also depends on this
number of individuals present then that
is capital n so if the value for R is
more so the value for n here will also
rise there right so individuals will
grow there okay so now let's see what
are the things that controls the
population size so see there are two
important things that regulates the
population size one is the density
dependent factors another one is the
density independent factors now here
density means the it depends on the
individuals of the population first
thing is the density dependent factors
if you take the example here as the true
sofala you see that development over the
time over the days and the number of
fruit flies that are present in the y
axis so you see if they have a kind of a
steep curve and we know that is a
sigmoid 'el or it's a logistic growth
curve where we witness a exponential
growth for the up to day 20
but after day 20 they receive a you know
the their environment receives the
carrying capacity it reached the
carrying capacity and then it kind of
stabilized to a specific growth rate
after that so here why these things are
happening there are certain density
dependent factors that means factors
which are collaborated due to the
presence of the number of individuals
and density dependent factor means in
this case this type of factors and this
type of growth depends on capital in of
the number of individuals in a
population if you see what are the
factors first is the competition
definitely density means competition
that means more and more fruit flies
they will be competition between them
there are two types of competition
possible inter species
and intraspecific intraspecific means
between the same species interspecific
means between two different species of
Drosophila fruit flies now second thing
is predation as there are competition
definitely there will be predation some
Drosophila when they want to live some
will not maybe in other population not
in case of Drosophila but in other
populations in wild if you see there
will be predation between same species
and different species
there will be parasitism parasitism
means in some case we all know about
what parasite is a means that one will
get the benefit by harming others so
that thing will also be present there
and fourth is the diseases so there will
be diseases out there right
diseases means as as that a huge amount
of individuals are out there there are
contaminations will be there and there
will be poly pollutions and
rising population will come with a
different side effects disease is one of
those side effects where the disease
will take place and it will kill some of
the individuals and in human population
disease due to our highly advanced
technology as well as the medical
science approaches we are going against
the disease as we are still I mean
growing and growing in populations now
the second type of factors that control
the population growth and population
size is the density independent factor
density independent factor means this
type of factors does not depend on the
individual so the number of individuals
out there in a population that means if
we take a population of 50 and if you
take a population of 5,000 this type of
factor will have the similar effect if
you place those two things together in
the same condition so if you take here
example our biotic factors that means
the temperature I mean the climate
everything under the climate temperature
moisture contained air and availability
of oxygen and everything then the
catastrophic events huge catastrophic
events that week I mean kill many people
at the same time if you put them on the
heart of 50 or 500 or 5,000 it doesn't
matter but in this catastrophic event
also there might be some survivor if you
have
more population size but in very less
case it's not so it's slightly affected
but if it's unpredictable most of the
most of the individuals of population
will die and will not depend on the
number of individuals that are present
in the population so that's for today
that's all about the population growth
and how it is controlled by different
factors and I hope you enjoy this
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