Module 9S1 Ecological Interactions

Lesson Summary

All species rely on defenses of some kind to reduce their chances of becoming a meal for another species. These can take the form of structural characteristics (thorns, claws), chemical characteristics (plant toxins, venoms) behaviors (territoriality, barking), or coloration (protective coloration, mimicry, and cryptic coloration). These defenses allow organisms from one species to protect themselves and to compete interspecifically with species that share the same trophic level. Slight variations in defenses between individuals of the same species (intraspecific competition) allow some individuals to compete better than their neighbors, changing allele frequencies in their favor. The greater the scarcity in a habitat, the more competition there is, thus the faster evolution occurs.