Quesitons on ArticleWhat emergent property is discussed in the red harverster ants?How is this property chemically achieved?What is the role of the control, and the positive control in this experiment?What information is shown in the caption of the graph?Why is this a bar graph rather then a line graph?What is the conclusion of the study in this “brief communication”?
Competition and niche differentiation in barnacles (Connell 1961)– Chthalamus more tolerant of dessication than Balanus– Balanus a more successful competitor – Chthalamus restricted to upper intertidal zone – realized niche < fundamental niche
– Testing the competitive exclusion principle • Two species of barnacles on intertidal rocks • Remove Balanus -- Chthamalus spread • Chthamalus distribution limited by Balanus High tide Chthamalus Chthamalus realized niche Balanus Balanus realized niche Ocean Low tide Figure 37.2A
Niches: fundamental and realized The fundamental niche is the n-dimensional hypervolume describing the full range of conditions that the species can use in the absence of competition • defined by an organism’s adaptations to persist in a given abiotic environment The realized niche is often smaller than the fundamental niche • restricted by factors eg, competition, predation, parasitism.
Modes of CompetitionIntraspecific: – Competition among members of the same species. – e.g. density dependent factorsInterspecific: – Competition among individuals of two or more different species • reduces fitness of both. • Interspecific competition can occur only if species have similar resource requirements – i.e. must have overlapping niches.
W are the Phytoplankton? ho Dia tom sDinofla ge lla te s phytoplankton Coccolitho
Gulf of Maine Data: W ilkinson and Jordan Basins Wilk. Basin Jordan Basin
The Redfield Ratio 106 Carbon : 16 Nitrogen : 1 Phosphorus Nucleic Acids CO2 Lipids Light Proteins Nutrients Carbohydrates (N, P, etc) Liebig’s Law:Growth of a “plant” is determined by availability of the single most limiting resource.Redfield