Question

480 CHAPTER 21 ANALYZING DATA 21.1 Does the Identity of Organisms Influence Energy Flow between Trophic Levels? Ecologists have noted that individuals and populations of 1. Plants non insect invertebrate herbivores- some species known as keystone species: see Concept small mammals large mammals 16.3) influence energy flow between trophic levels more 2. Algae - aquatic non-insect invertebrate herbivores than others. In particular, we've seen several examples in -insect predators - fish which invasive species have greatly altered energy transfers 3. Plants - large mammal herbivores -- large mammal as well as diversity within communities. Attention has largely predators - large mammal predators been focused on the behavioral characteristics of a species, such as how effective individuals of a species are at hunt 4. Plants - insect herbivores insect predators - ing or grazing, or its population dynamics leg, whether a insect predators population exhibits exponential growth; see Concept 10.3). 5. Remembering that the transfer of energy between Additionally, the thermal physiology and sizes of the species trophic levels can influence the number of trophic making up a trophic level can influence how much energy levels an ecosystem can sustain, and that greater makes it from one trophic level to the next energy transfer usually enhances the establishment Using information from the text and Table 21.1. provide of higher tropic levels, which of the hypothetical food a rough estimate of how much energy would make it to chains in Questions 1-4 would be most likely, and the second third, and fourth trophic levels in the following which least likely to sustain the highest trophic level? simplified food chains. Start with 100 units of energy in the See the companion website for autotrophic base of each of these food chains lie, plants or algae). Assume the production efficiencies for endotherms a similar Analyzing Data exercise. do not vary according to diet. 34 32 The wereld The more trophic levels tsustained Number of trophic levels larger population sizes, which are less prone to local ex- tinction (see Concept 11.3). Larger ecosystems also have more habitat heterogeneity and thus tend to have higher species diversity Support for the effect of ecosystem size on the number of trophic levels is derived primarily from studies of lakes and oceanic islands, ecosystems with discrete boundaries. For example, Gaku Takimoto and colleagues (2008) tested the relative effects of disturbance and island size on the number of trophic levels on 36 islands in the Bahamas. The effect of disturbance was tested by examining 33 of the smaller islands that were either exposed to (19 islands or protected from (14 islands) storm surges. The number of trophic levels was estimated using isotopic ratios of carbon and nitrogen (as described in Concept 20.4) in tissues from the top predators, spiders and lizards. Takimoto and col leagues found that exposure to storm surges had no effect on the number of trophic levels. However, disturbance did influence the identity of the top predators orb spiders were more frequently the top predators on exposed islands, and Anolis lizards were at the apex of the food web on pro- tected islands. Island sixe, however, was strongly correlated with the number of trophic levels (FIGURE 21.14 providing evidence that ecosystem size can influence the number of trophic levels in a terrestrial ecosystem Weturn our attention next to a more detailed investiga- tion of trophic relationships in ecosystems as we cross the 26 24 . OP 15 10° 10 Ecosystem FIGURE 21.14 Ecosystem Size is Correlated with the Number of Trophic levels On islands in the Bahamas, Tokimoto and colleagues found that as island size increased, the number of trophic levels also increased. After G. Takimoto et al. 2008. El 89.3001-2007)

Answer 1

Yes, the Identity of organisms influence the energy flow between tropic levels.

The organisms size, feeding habits, population growth rate have great influence on the energy flow in that ecosystem from producers to the consumers.

Small sized organisms use less energy and transfers major amount of that energy. Also the feeding habit effectively influence the energy flow. The grazing animals are primary consumers and uses the initial 10% of the energy. The remaining energy portion is transferred to the next consumer. The hunting animals are the primary and secondary and so on consumers and they get the 10% of the remaining energy.

The 4th numbered food chain sustains more energy for energy flow according to our conclusion and 3rd food chain of the ecosystem is less sustainable for the energy flow because it contains the larger mammals as primary consumers and also as secondary and tertiary consumers and much energy is consumed by them.