Population Dynamics, Species Interactions and Carrying Capacity

1
Population Dynamics, Species Interactions and
Carrying Capacity
2

• Population Dynamics

3
Population dynamics

• Changes in pop size, density, dispersions and age
  distribution
• Population size- in population at given time
• Pop density- in certain space at given time
• per unit area
• Pop dispersion-spatial patterns of individuals in
  the habitat

4

• Two ways to increase population
• Birth
• Immigration-individuals move into an area from
  someplace else
• immigrants

5

• Two ways to decrease population
• Death
• Emigration-move away from location to someplace
  else
• emigrants

6

• Population grows when
• births immigrants gt deaths
  emigrants
• Population shrinks when
• deaths emigrantsgt births immigrants

7
Species Interactions
8
The ecological niche

• Lifestyle or way of life
• Range of conditions and resources needed for each
  individual specie

9

• Generalist species
• broad niches
• can utilize variety of conditions and resources
• Specialist species
• narrow niche, need specific c r
• tiger salamander-only breed in fishless ponds
• red-cockaded woodpeckers-only nest in trees gt75
  yrs

10
Overlapping niche increased competition

• Significant overlap
• one species must migrate away
• one species shifts feeding or behavior through
  natural selection evolution
• one species out-competed, declines
• one species becomes extinct

11
Species interactions

• Inter-specific competition-between species for
  limited resources
• Predation-one species feeds on all or part of
  another species
• predator benefits prey harmed
• Symbiosis-long lasting relationship between
  species that rely upon each other

12
3 types of symbiosis

• Parasitism-one species feeds on another w/o
  immediately killing
• one helped, one harmed
• Mutualism-interactions benefit both species
• Commensalism-one species benefits other neither
  harmed or helped

13
Labeling species place in ecosystem

• Native species-normally live and thrive in
  ecosystem
• Nonnative/exotic/alien species-have migrated
  into, been introduced by humans deliberately or
  accidentally an ecosystem

14
Carrying Capacity
15
C Ca ar pr cy iI tn
yg
16
(No Transcript)
17
(No Transcript)
18
WHAT DOES THIS MEAN?
19
COPY THIS IN YOUR NOTES
Dieback
20
Carrying Capacity

• The number of individuals of a species that an
  ecosystem can support WITHOUT the ecosystem being
  degraded (damaged) over time.

21
Carrying Capacity

• As a population grows, it takes more resources
  from its habitat.
• Population low, plenty of resources to go around
• Leads to increased birth rates and increased
  population
• Increased population stresses availability of
  resources

22
Carrying Capacity

• Species may overshoot their habitats carrying
  capacity for a short time until lack of resources
  causes a dieback or crash in the population.
• Three choices (1) die (2) new resources (3)
  move

23
Carrying Capacity

• As resources become scarce, individuals compete
  for them and the death rate will rise because
  those who cannot compete die

24
Carrying Capacity

• Birthrates decrease because producing offspring
  requires resources.

25
Carrying Capacity

• Death and lower birth rates cause the population
  growth to slow eventually the population may
  stop growing when the number of deaths equals the
  number of births.

26
Limiting Factors

• A stable population is the result of the
  interaction between factors tending to increase
  population (biotic potential) and factors that
  decrease population (environmental resistance)

27
Limiting Factors

• Limiting factors slow the growth of a
  population
• Density Dependent depends on the size of a
  population. Larger effect as populations grow
• Density Independent limits population growth
  regardless of size, all members affected equally

28
INDEPENDENT
CLIMATE
NATURAL DISASTERS
HUMAN DISTURBANCE
POPULATION SIZE
LIVING SPACE/ SHELTER
PREDATION
PARASITISM
WATER
DISEASE
FOOD
DEPENDENT