Transcript Competition Within a Population

Chapter 8
pg 210
Understanding
Populations
What is a population?

“all the members
of a species living
in the same place
at the same time”
Properties of Populations
1.
Density “the number of
individuals per
unit area or
volume”
Ex - # bass fish per
cubic meter of
water
2.



Dispersion –
“ the relative
distribution or
arrangement of
it’s individuals in
a given amount of
space”
Even
Clumped
Random
Growth Rate

Change in pop. size =
Births – Deaths
If adults in a population are not
replace by new births, the growth rte
will be negative and the population
will shrink
How Fast can the Population
Grow?
Biotic Potential =
Fastest rate at which
its population can
grow.

Limited by:
The organism’s:
Repro. Potential
Reproductive Potential
1. Number of
offspring produced
at one time
2. How often does
the organism
reproduce
3. how soon can the
organism
reproduce (age!?)
Exponential Growth


Population growth
that grows faster
and faster!
Produces a JShaped curve
Limits to population Growth
1. Carrying Capacity
 2. Resource Limits
 3. Competition within a population

1. Carrying Capacity

Defined as the
maximum
population
(number) that the
ecosystem can
support.

Will crash when it
reaches capacity
due to disease, etc.
2. Resource Limits
A particular resource that is
consumed by a particular species
(food, water, etc) is called a
“LIMITING FACTOR”
 CC is reached when the species is
consuming it at the same rate it is
being produced.

3. Competition Within a Population

= Members of a population use the
same resources in the same way so
they will eventually compete with
one another as the population
approaches it carrying capacity.
Ex = Christmas time
and Limited toys

2 types of Competition:
Direct
= direct fighting for
resources
Ex – food
Ex – Limited # of Elmo
dolls at target at an
8 am sale and
400 mommies
waiting outside!
Indirect
= indirect fighting for
resources
Ex- nocturnal vs. diurnal
Ex – mommy arrives at
a 24 hour Target and
buys the last doll
before another
mommy arrives at 8
am!
Two types of population
Regulation:
=The cause of death to regulate the
population size can be:
Density Dependant
Density Independent
1.
2.
S – Curve Growth
Mimics a “S”
 Population starts slow, then
increases quickly, then begins to
level off to support the current
population at it’s maximum capacity.

Density Dependant
= Death occurs more quickly in a
crowded population than a sparse
one.
Density Independent
death that is
caused
regardless of
the pop.’s
density.
It affects all
members of a
population in a
general/similar
way.
=
8.2 How species interact with each
other (pg. 217)
Niche
= role in the
ecosystem.
Ex – physical
home, env
factors for its
survival, and its
interactions with
others.
Habitat
= location.
Ex -Where an
organism lives
Species Interactions
page 218
= based on whether each species
causes benefit or harm to the other
species in a given relationship.
1. Competition
2. Predation
3. Parasitism
4. Mutualism
5. Commensalism
Competition
Defined as both
species being
harmed.
May be in
competition for
mates, territory,
food, etc.
Predation
=
defined as:
benefits one
and
harming
the other
Mutualism
= defined
as:
Benefits
both!
Parasitism
=
defined as:
benefits
one, harms
the other
Commensalism
= defined as
one benefits
and the
other is
unaffected.
Symbiosis and
Coevolution


Symbiosis is the
relationship in
which 2 species
interact.
Typically in which
one benefits.
Coevolution may
occur b/w species
in close
relationship.
- Without one, the
other will die!
