Population and Relationships

1
Population and Relationships

• Population and growth
• Limiting factors
• Population growth curves
• Exponential
• Logistics
• Symbiotic relationships

2
Population and Growth

• Population- consists of all individuals of the
  same species that live together in one place at
  one time.

3
Population and Growth

• Biodiversity- the number and variety of organisms
  in a given area during a specific period of time

4
Population and Growth

• In order to predict population growth the
  following must be considered
• Population Size
• Population Growth Rate
• Carrying Capacity
• Limiting Factors

5
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)

6
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

7
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

8
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.

9
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!

10
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.

11
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

12
Population Growth CurvesLogistic

• Logistic 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
13
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

14
Symbiotic Relationships

• Mutualism- Both Benefit
• Example- Lichen (fungus and algae together)

• Fungi provides-
• carbon dioxide
• moisture
• Algae provides-
• food
• oxygen

15
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

16
Symbiotic Relationships

• Parasitism- one benefits (parasite), other harmed
  (host)
• Example- flea and a dog

• Flea
• Food
• Shelter
• Dog
• Itches
• Can become infected with diseases

17
Fill out the chart
benefits, - harmed, 0 neutral (neither
harmed nor helped)
Symbiosis Type Organism 1 Organism 2 Example
Mutualism
Commensalism
Parasitism



0
-