7.1.3 Biotic Factors

Key Biotic Factors and Their Effects on Communities

1. Food Availability

• The amount of food available in an ecosystem directly affects the population size of organisms.
• Impact: When food is plentiful, organisms can breed more successfully, leading to an increase in population. Conversely, a shortage of food can cause populations to decline.

2. New Predators

• The introduction of a new predator to an ecosystem can have a significant impact on existing species.
• Impact: New predators can reduce the population of prey species, potentially leading to their decline or even extinction if they cannot adapt or escape.

3. New Pathogens

• Pathogens are disease-causing organisms like bacteria, viruses, or fungi.
• Impact: If a new pathogen is introduced to a community, the population may have no immunity or resistance to it, leading to rapid spread of disease and potentially wiping out large portions of the population.

4. Competition

• Competition occurs when different species or individuals within a species vie for the same resources, such as food, water, or territory.
• Impact: If one species is better adapted to the environment than another, it will outcompete the less adapted species. This can lead to a decline in the population of the less adapted species, sometimes to the point where they cannot reproduce and may face local extinction.