4.7.1.3 biotic factors

• what are the main biotic factors that affect communities?

  availability of food, new pathogens or parasites, new predators arriving and interspecific competition
• how does the availability of food affect communities?

  when food is in short supply, animals struggle to survive and often do not breed
• how do new pathogens or parasites affect communities?

  organisms have no resistance to the disease so a new pathogen could damage or even wipe out populations in a community
• how do new predators arriving affect communities?

  they have no defenses and may quickly be wiped out
• what is interspecific competition and how does it affect communities?

  competition between species - a new species may outcompete another to the point where the population has become too low for successful breeding