Quesitons on Article
What emergent property is discussed in the red
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
Why is this a bar graph rather then a line graph?
What is the conclusion of the study in this “brief
– Chthalamus more tolerant
of dessication than Balanus
– Balanus a more successful
– Chthalamus restricted to
upper intertidal zone
– realized niche < fundamental
Competition and niche
differentiation in barnacles
– Testing the competitive exclusion principle
• Two species of barnacles on intertidal rocks
• Remove Balanus -- Chthamalus spread
• Chthamalus distribution limited by Balanus
Niches: fundamental and
The realized niche is often smaller than the
• restricted by factors eg, competition,
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
Modes of Competition
– Competition among members of the same species.
– e.g. density dependent factors
– Competition among individuals of two or more
• reduces fitness of both.
• Interspecific competition can occur only if species have
similar resource requirements
– i.e. must have overlapping niches.
Who are the Phytoplankton?
Gulf of Maine Data: Wilkinson
and Jordan Basins
(N, P, etc)
The Redfield Ratio
106106 Carbon : 1616 Nitrogen : 11 Phosphorus
Liebig’s Law:Liebig’s Law:
Growth of a “plant” is determined by availability
of the single most limiting resource.
Figure 1. A conceptual model of the whale pump.
Roman J, McCarthy JJ (2010) The Whale Pump: Marine Mammals Enhance Primary Productivity in a Coastal Basin. PLoS ONE
5(10): e13255. doi:10.1371/journal.pone.0013255