Concept of radiometric dating
Differences in the ability of species to distribute themselves across space have distinct consequences for the structure of communities.
Doesn't this fact support the notion that simple organisms evolved into more and more complex organisms over time, with the more complex organisms buried and fossilized above the earlier and simpler life forms?
Some species use a wider range of resources or persist across a wider range of habitats than others (Brown, 1984; Brown et al., 1996; Hanski and Gyllenberg, 1997).
Generally, species that use a wide range of resources or tolerate a variety of abiotic conditions can establish more populations in more places than comparable species with relatively narrow niches (Brown, 1995; Cook and Quinn, 1995).
Many of the layers also show a certain specialization.
Some layers contain mostly fish fossils while others contain land-dwelling creatures such as dinosaurs.