may be acted upon by their environment, and they may react upon it. If a set of properties in either system changes in such a way that the action of the first system on the second changes, this may cause changes in properties of the second system which alter the mode of action of the second system on the first.” Robert MacArthur Robert MacArthur (1930–1972) is best known in the field of Evolutionary Ecology for his work The Theory of Island Biogeography, in which he and his co-author propose “that the number of species on any island reflects a balance between the rate at which new species colonize it and the rate at which populations of established species become extinct.” Eric Pianka According to the University of Texas, Eric Pianka’s (1939–present) work in evolutionary ecology includes foraging strategies, reproductive tactics, competition and niche theory, community structure and organization, species diversity, and understanding rarity. Pianka is also known for his interest in lizards to study ecological occurrences, as he claimed they were “often abundant, making them relatively easy to locate, observe, and capture.” Michael Rosenzweig Michael L. Rosenzweig (1941–present) created and popularized Reconciliation ecology, which began with his theory that designated nature preserves would not be enough land to conserve the biodiversity of Earth, as humans have used so much land that they have negatively impacted biogeochemical cycles and had other ecological impacts that have negatively affected species compositions. Other notable evolutionary ecologists R. A. Fisher (1890–1962), whose 1930 fundamental theorem of natural selection recognised the power of rigorous application of the theory of natural selection to population biology. David Lack (1910–1973), a follower of Charles Darwin, worked to merge the fields of evolutionary biology and ecology, focusing mainly on birds and evolution. Thierry Lodé (1956–present), a French ecologist whose work focused on how sexual conflict in populations of species impacts evolution. Research Michael Rosenzweig's idea of reconciliation ecology was developed based on existing research, which was conducted on the principle first suggested by Alexander von Humboldt stating that larger areas of land will have increased species diversity as compared to smaller areas. This research focused on species-area relationships (SPARs) and the different scales on which they exist, ranging from sample-area to interprovincial SPARs. Steady-state dynamics in diversity gave rise to these SPARs, which are now used to measure the reduction of species diversity on Earth. In response to this decline