3.1 - Competition

Competition for resources

• Every organism needs a supply of resources from its surroundings and from other organisms in order to survive and reproduce.
• These resources are limited, so organisms must compete for them.
• The organisms that compete most successfully for resources in short supply are most likely to survive, reproduce, and pass on their characteristics. Those that compete less successfully may not get enough to survive.

What organisms compete for

• Plants - Compete for light and space above ground, and for water and mineral ions from the soil
• Animals - Compete for food, water, territory (space to live in), and mates so they can breed

Two types of competition

1. Interspecific competition - Competition between individuals of different species, such as lions and hyenas competing for the same prey
   • Different species usually overlap in only one or a few of the resources they need, so this competition is for those shared resources only
2. Intraspecific competition - Competition between individuals of the same species, such as male deer competing for mates
   • Members of the same species need exactly the same set of resources, so they compete for all of them - this makes intraspecific competition more intense than interspecific competition