BIOB50H3 Chapter Notes - Chapter 8: Sea Urchin
16 Jan 2012
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We can best prevent the decline of populations we want to protect if we have a clear understanding of what determines their distribution and abundance. If there were 2500 lizards on a 20-hectare island, the population size would be 2500 lizards, and the population density would be 125 lizards per hectare y. In some cases, the total area occupied by a population is not known. When the area isn t fully known, an area is delimited based on best available knowledge of the species. It is often difficult to know how far organisms or their gametes can travel. Abundances change over time and space y abundance can change over time and space and some species vary more than others. E. g. a 6-year study of 23 species of insects that fed on goldenrod showed that although the sites had similar climatic conditions every year, insect abundances varied greatly. Dispersal links populations y organisms differ greatly in their capacity for movement y.
