Succession• Definition: Ecological succession is a process in which communities of plant and animal species are replaced in a particular area over time by a series of different and usually more complex communities.
Succession• Primary – succession based on natural development of communities – Algae, moss, grasses, trees• Secondary – succession based on “event”, which usually causes a return to a state similar to its original state – Tree falling, volcano, hurricane
Succession• G.2.7: Outline the changes in species diversity and production during primary succession. – Not very diverse: Lichen pioneer species – Very diverse: Forest climax community
Succession• G.2.8:Explain the effects of living organisms on the abiotic environment, with reference to the changes occurring during primary succession. – Small amount of soil formed by the lichens is colonized by mosses, which do not have roots and require little soil – As the seedless plants live and die decomposition increases the richness of the soil – Grasses can successfully grow
Niche• G.1.5 Explain what is meant by the niche concept.• The total of a species’ use of biotic and abiotic resources is called the species’ ecological niche. – Habitat – Feeding relationships – Symbiotic/other interactions with organisms
Niche• Fundamental niche = where the species is designed to live the best• Realized niche = where the species actually resides because of competition
Niche• G.1.7: Explain the principle of competitive exclusion.• two species competing for the same limiting resources cannot coexist in the same place – one must leave or becomes extinct
InteractionsG.1.6:Outline the following interactions between species (with examples):• Competition• Herbivory• Predation• Parasitism• Mutualism