Competitive strategies of micro organisms

1. COMPETITIVE STRATEGIES OF MICRO-
ORGANISMS
PRESENTER NAME : ABU BAKAR BUTT
ROLL NO. : 856 (023827)
8TH SEMESTER
DISCIPLIN : BS ZOOLOGY
PRESENTED TO : DR. SAGHIR AHMAD SAHAB

2. Ecological competition
Ecological competition is the between two organisms or the same resources within an
environment. Resources are components of the environment that are required for the
survival and reproduction such as food, water, shelter, light, territory, and substrate.
The organisms may be of the same species or may be relate with different species.
INTRA-SPECIFIC COMPETITION: A competition in population ecology, whereby
members of the same species compete for limited resources. This leads to a reduction in
the fitness for both individuals, but the more fit individual survives and is able to
reproduce.
INTER-SPECIFIC COMPETITION: A competition in which individuals of different species
compete for the same resources in an ecosystem

3. Mechanisms of competitions
Competition occurs by various mechanisms, which can generally be divided into direct and
indirect. these apply equally to intraspecific and interspecific competition. biologists typically
recognize two types of competition: interference and exploitative competition.
INTERFERENCE competition occurs directly between individuals via aggression etc. when the
individuals interfere with foraging, survival, reproduction of others, or by directly preventing their
physical establishment in a portion of the habitat.
EXPLOITATION competition occurs indirectly through a common limiting resource which acts as
an intermediate. For example, use of resources depletes the amount available to others, or they
compete for space.

4. COMPETITIVE STRATEGIES
STRATEGY NO. 1
 EXCEPT IN THE VERY SIMPLEST OF ENVIRONMENTS, HOWEVER, THE MOST
SUCCESSFUL ORGANISM IS THAT WHICH CAN RESPOND MOST EFFECTIVELY TO
A MULTI-FACTORIAL MATRIX OF STRESS FACTORS. AT THE SAME TIME, KEY
FACTORS MAY BE UNRELATED. THE OUTCOME OF COMPETITION BETWEEN
TWO MICRO-ORGANISMS IN A GIVEN ENVIRONMENT MAY BE DETERMINED BY
WHETHER THE BENEFIT GAINED BY ONE ORGANISM BY ITS RESPONSE TO
FACTOR A (E.G. EFFICIENCY OF NUTRIENT UTILIZATION) IS GREATER THAN THE
BENEFIT GAINED BY THE OTHER ORGANISM IN RESPONSE TO FACTOR B (E.G.
LOW PH VALUE).

5. STRATEGY NO. 2
IN MANY CASES, COMPETITION IS BETWEEN MICRO¬ ORGANISMS WHICH, PHYSIOLOGICALLY AT
LEAST, ARE CLOSELY RELATED. THIS IS FAIRLY OBVIOUS, SINCE TWO MICRO-ORGANISMS WHICH
RESPOND IN THE SAME, OR SIMILAR, WAYS TO ENVIRONMENTAL STRESS ARE LIKELY TO
COMPETE IN THE SAME NICHE.
 THE SUCCESSION OF DIFFERENT KARYOTYPES OF SACCBAROMYCES CERVISIAE RESULTS FROM
THE RELATIVE COMPETITIVE ABILITY OF EACH IN CONDITIONS OF FALLING SUGAR AND RISING
ALCOHOL CONTENT.
 MANY MODERATELY HALOPHILIC BACTERIA, FOR EXAMPLE, CAN GROW OVER A REMARKABLY
WIDE RANGE OF NACL CONCENTRATIONS, BEING THE DOMINANT ORGANISM AT SOME
CONCENTRATIONS.
 OTHER MICRO¬ ORGANISMS HAVE TWO, OR MORE, SETS OF KEY ENZYMES THAT ARE
INDUCED IN RESPONSE TO DIFFERENCES IN ENVIRONMENTAL CIRCUMSTANCES, SUCH AS
REDUCED TEMPERATURES.

6. STRATEGY NO. 3
COMPETITION DOES NOT ALWAYS INVOLVE PHYSIOLOGICALLY SIMILAR MICRO-
ORGANISMS, BUT CARE IS REQUIRED TO DECIDE WHICH SITUATIONS ARE TRULY
COMPETITIVE.
 THE ABILITY OF AEROBIC AND ANAEROBIC BACTERIA TO COEXIST IN SOIL, FOR
EXAMPLE, WAS LONG AN ENIGMA FOR SOIL MICROBIOLOGISTS, SINCE IT
WOULD BE EXPECTED THAT ONE CATEGORY WOULD RAPIDLY ATTAIN
DOMINANCE. THUS AEROBES AND ANAEROBES ARE EFFECTIVELY CAPABLE OF
GROWTH SIDE- BY-SIDE.
 TRUE COMPETITION BETWEEN PHYSIOLOGICALLY DISTINCT MICRO-ORGANISMS DOES
EXIST, AN EXAMPLE BEING THAT IN MICRO-OXIC ENVIRONMENTS BETWEEN
MICROAEROPHILIC BACTERIA AND SOME AEROBES. IN SUCH SITUATIONS, IT WOULD
BE EXPECTED THAT MICRO- AEROPHILIC BACTERIA WOULD BE DOMINANT.

7. True competition between physiologically
distinct micro-organisms does exist, an example
being that in micro-oxic environments between
microaerophilic bacteria and some aerobes. In
such situations, it would be expected that
micro- aerophilic bacteria would be dominant.

8. THANK YOU