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Population and Relationships. Population and growth Limiting factors Population growth curves Exponential Logistics Symbiotic relationships. Population and Growth. Population- consists of all individuals of the same species that live together in one place at one time. - PowerPoint PPT Presentation
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Population and Relationships
Population and growthLimiting factors
Population growth curvesExponentialLogistics
Symbiotic relationships
Population and Growth• Population- consists of all individuals
of the same species that live together in one place at one time.
Population and Growth• Biodiversity- the number and variety of
organisms in a given area during a specific period of time
Population and GrowthIn order to predict population growth the
following must be considered:• Population Size • Population Growth Rate • Carrying Capacity• Limiting Factors
Population and Growth• Population size- the number of
individuals in a population
• Population growth rate- the rate at which the birthrate is greater than the death rate.
(Growth occurs when more individuals are being born than dying in a population)
Population and Growth• Carrying Capacity- the population size
that an environment can sustain• Limiting Factors- Factors That Control
Population Growth» Competition» Predation» Parasitism» Crowding» Stress » Disease
Population and GrowthLimiting Factors
Competition- Situation in which two or more organisms attempt to use the same scarce resource
Primary sources of Competition:
• Food• Water• Space• Mates
Population and GrowthLimiting Factors
Predation- A relationship between two organisms in which one organism kills (predator) and devours another organism (prey).
- Affects population size of both predator (increases) and the prey (decreases).
- Often cyclical.
Population and GrowthLimiting Factors
• Parasitism- The relationship between two organisms where one organism benefits (parasite) and the other is harmed (host).
Example: Tapeworm• You are harmed because it
lives off your intestinal fluids• Segments break off to form a
new worm!
Population and GrowthLimiting Factors
• Crowding- exceeding the carrying capacity of a habitat which can result in stress and disease.
• Stress and disease can lead to poor reproductive success and can cause damage to the habitat.
Population Growth CurvesExponential
Exponential growth:
• Population increases by a constant proportion per unit of time
• At this growth rate the population exhibits a J-shaped curve
Population Growth CurvesLogisticLogistic growth:
• Population increases rapidly for a period of time, its growth begins to slow, and ultimately, growth stops (the birthrate and death rate become equal).
• At this growth rate the population exhibits an S-shaped curve.
• K (carrying capacity) = maximum population size that an environment can support
K
Symbiotic Relationships• Symbiosis- a close long term
relationship between two or more species that can be beneficial or harmful
Beneficial:• Mutualism= Both benefit• Commensalism= Only one
benefits & other is not harmed or helped
Harmful:• Parasitism= One benefits &
Host slowly harmed
Symbiotic RelationshipsMutualism- Both BenefitExample- Lichen (fungus and algae
together)Fungi provides-
• carbon dioxide• moisture
Algae provides-• food• oxygen
Symbiotic Relationships• Commensalism- one benefits, the other is
neither harmed or helped• Example- whale and a barnacle
Whale – unharmed
Barnacles– Protection from
predators– Transportation to new
food sources
Symbiotic Relationships• Parasitism- one benefits (parasite),
other harmed (host)• Example- flea and a dogFlea
– Food – Shelter
Dog– Itches– Can become infected
with diseases
Symbiosis Type
Organism 1
Organism 2
Example
Mutualism
Commensalism
Parasitism
+ = benefits, - = harmed, 0 = neutral (neither harmed nor helped)
Fill out the chart:
+ +
+
-+
0