G1 Niche How do species interact with one another? In your blog: What is a ‘niche’? Feedback distributer: Maria Elisa

G1.5 The Niche Concept Niche = mode of existence of species in an ecosystem Includes Habitat: where species lies in the ecosystem Nutrition: how species obtains its food Relationships: the interactions with other species in the ecosystem

G1.7 Competitive exclusion No two species in a community can occupy the same niche  “Complete competitors cannot coexist” Gause set up experiments involving three species of Paramecium in a medium of oatmeal with bacteria or yeast. P. aurelia with P. caudatum: competitive exclusion P. caudatum with P. bursaria: P.caudatum was feeding on bacteria whereas P. bursaria was feeding on yeast  niches not identical

G1.8 Fundamental and realized niches Fundamental niche = potential mode of existence, given the adaptations of the species niche that an organism functionally could live in in the absence of competitors or other interacting species Realized niche = actual mode of existence, which results from its adaptations and competition from other species Niche that organism is actually found, following all interactions with other species Barnacle competition: Field experiments on barnacles were carried out by Connell in 1961 on rocky shores on Scotland two species of barnacle; Chthamalus stellatus and Balanus balanoide C. Stellatus can occupy middle intertidal; but in presence of B. balanoides it prefers to live further up shore

G1.8 Fundamental and realized niches

G1.8 Fundamental and realized niches

Interactions between species Competition Predation Symbiosis Mutualism Commensalism Parasitism

Interactions between species Find the definition of the following: Competition, Predation, Symbiosis, Mutualism, Commensalism, Parasitism Check i-biology (G1 community ecology) 2. For your chosen ecosystem, provide an example of each one of the interactions in the Google doc shared with you.