Interspecific Relationships

1
Interspecific Relationships

• Interactions between individuals from another
  species

2
Competition

• This tends to be less intense than intraspecific
  because of a difference in the species niche
• This can be for the same resources, eg
• Food
• Light
• Water
• Space
• Homesites etc
• The severity of the competition depneds on the
  overlap in needs of the different organisms and
  the supply of the resource that is being competed
  for.

3
Predator/Prey Relationships

• Can be density dependent the intensity of the
  relationship increases as the density of the
  interacting populations decreases
• Can be density independent the intensity of the
  relationship does not change according to the
  density of either party
• Predators and parasites can be limiting or
  regulating

4
Predation Tactics

• There are a multitude of strategies used by
  predators in order to find, catch and kill their
  prey
• Trapping
• Ambushing
• Stalking
• Chasing
• Echolocation
• The senses
• Camouflage
• Mimicking

5
Predation Avoidance

• The strategies used by prey animals are diverse
• Camouflage
• Hiding
• Freezing
• Running away
• Toxin use
• Bluff
• Mimicry
• Batesian mimicry
• Muellerian mimicry

6
Succession

• The replacement of one species by another over
  time
• Organisms appear in succession
• Each one modifies the environment to make it
  suitable for the next species until a climax
  community forms in which a species replaces itself

7
Stratification

• Vertical relationships in space with other
  organisms
• Could be
• Layers of vegetation in a forest
• Layers of animals in a tropical forest
• Layers of animals as you go down the depth of the
  ocean to the bottom of the sea

8
Symbosis living together

• Mutualism
• Commensalism
• Antibiosis
• Exploitation
• The evolution of predator or parasite tends to go
  hand in hand with the evolution of the host or
  prey as each in the relationship tried to gain an
  advantage.
• Predation
• Parasitism

Co-operation
9
Summary of Interspecific Relationships
Relationship Species A Species B
Mutualism
Commensalism 0
Neutrality 0 0
Antibiosis 0 -
Expolitation -
Competition - -