Populations: Intraspecific Relationships (HL IB Biology)

Intraspecific relationships

• Intraspecific relationships involve interactions between individuals of the same species
  • 'Intra' = within
• Intraspecific relationships can involve
  • Cooperation
    • Both members of the relationship benefit from the interaction
  • Competition
    • One member of a relationship outcompetes the other and is more successful

Intraspecific cooperation

• In this type of relationship, members of a species work together to aid survival of a group, e.g.
  
  • Orcas show cooperative hunting behaviour, working together to catch specific types of prey and then sharing the food that they catch
  • Meerkats divide the roles in their groups between multiple individuals, so some will watch for predators while others watch young or hunt for food
  • Many species of ants work together in large groups to build nests and provide food for developing young

CC BY 4.0, via Wikimedia Commons

Orca can cooperate with each other during hunting to create a wave that can wash seals into the water. This particular seal eventually escaped on this occasion, but working together increases the chances of hunting success for the orca.

Intraspecific competition

• Individuals of the same species have the same needs, and so they are frequently in competition with each other for the same resources, e.g.
  • Plants will compete with members of the same species for:
    • Light
    • Minerals
    • Water
    • Space
  • Animals will compete with members of the same species for:
    • Food
    • Mates
    • Territory (which will increase access to food and mates)
• Examples of intraspecific competition include
  • Male red deer fight with each other for access to females, and the dominant male will mate with all of the females in the group
  • Robins are aggressive towards other robins in order to defend their territory; they are so fiercely territorial against other robins that they will even attack bunches of red feathers
  • Oak trees growing close to each other in a woodland will be competing for light, water, and minerals
• Note that not all examples of intraspecific competition involve visible conflict; individuals with overlapping territories will be consuming the same resources, so the food that is eaten by one individual will no longer be available for another; these individuals are in competition with each other

Public domain, via pxhere

Red deer males bellow to show their dominance as part of their competition for females