ECOSYSTEMS

Key Concepts How do biotic & abiotic factors influence an ecosystem? What interactions occur within communities? What is ecological succession?

Abiotic vs. biotic The biological influences on organisms within an ecosystem are called biotic factors. Plants, bacteria, animals (living factors) Physical or non-living factors that shape ecosystems are abiotic factors. Precipitation, humidity, sunlight, etc. Together, biotic and abiotic fact determine the survival & growth of an organism.

Abiotic vs. biotic (cont.) An area where an organism lives is called a habitat. A habitat includes both abiotic and biotic factors.

Niche A niche is the full range of physical and biological conditions in which an organism lives. Includes the type of food, how its obtained, and what species eat the food. Also includes how and when it reproduces. No two species can share the same niche in the same habitat. Habitat vs. niche

Community Interactions Competition, predation, and various forms of symbiosis affect an ecosystem. Predation – an interaction in which an organism captures and feeds on another organism. Predator and prey

Community Interactions Symbiosis – A relationship in which two species live closely together “living together” 3 main classes of a symbiotic relationship Mutualism Commensalism Parasitism

Symbiosis relationships Mutualism – both species benefit Insects and flowers Commensalism – one organism is benefited the other is neither harmed nor helped. Barnacles on whales Parasitism – one organism lives and harms another organism. Tapeworms inside mammals

Symbiosis relationships

Ecological Successions The series of predictable changes that occurs in a community over time is called ecological succession. Successions that occur on surfaces where no soil exists is called primary succession. Volcanic eruptions, glaciers, etc. Pioneer species are first to populate an area Succession following a disturbance that destroys a community After wildfires, floods, etc.

Organization in ecosystems Species: a group of organisms so similar they can breed Population: groups of individuals belonging to the same species Communities: assemblies of different populations that live together Ecosystem: collection of all organisms in a particular place. Biome: group of ecosystems that have the same climate.