Please enable JavaScript.
Coggle requires JavaScript to display documents.
The quick and the dead: correctional selection on morphology, performance,…
The quick and the dead: correctional selection on morphology, performance, and habitat use in island lizards.
Questions Being Asked: 1. How does natural selection interact with multiple traits at once? 2. Can the environment an organism is in influence multiple traits at once? Can natural selection influence trade-offs in morphology and performance development.
- The researcher's hypothesis: A lizard that has long legs that can maneuver fastest on broad surfaces and displayed a preference for broad surfaces in nature will also display an increase in fitness. The speed and endurance of Anolis lizards are influenced by environmental pressures.
- Dependent Variable: The fitness of the lizards. Independent variable: Performance (locomotion relative to habitat)(measurement taken as sprint sensitivity)(The difference in speed given the surface type; broad vs. narrow), morphology (hind-limb length), and resource use (habitat usage).
- Controls: All local population females were allowed to maintain their natural population densities. All islands maintained similar average temperatures and precipitation. Each island was cleared of local males to prevent interactions that could impact datum.
Experiment Description: Anolis lizards were taken from an island in the Greater Antilles and transplanted to two different proximal islands to areas dominated by broad or narrow surface foliage. The lizard's fitness was then tracked over a duration of four months.
What were the results: - Locomotion and endurance was negatively correlated with sprint sensitivity.
- Researchers were able to establish a significant correlation between sprint sensitivity, habitat use and inproved fitness.
- Lizards that benefited from a broad or narrow surface displayed increased fitness.
- Significant statistical correlation between the independent variables was only observed in male lizards.
- The data supports the hypothesis that natural selection applies pressure to multiple traits simultaneously and steers adaption.
- There are other possible influences unrelated to natural selection that may steer multiple traits and improve fitness such as sexual selection and increased population densities.
Definition: Sprint sensitivity was defined as the difference in peak performance on either a broad or narrow surface.
My Lingering Questions: Are the results obtained consistent when different independent variables and a new organism is tested?
- Performance, morphology and resource are still the categories being monitored but in birds.
- Habitat use, wing structure, and flight sensitivity would be the areas of focus.
-
Citation: Calsbeek R, Irschick D. 2007. The quick and the dead: correctional selection on morphology, performance, and habitat use in island lizards. Evolution. 61(11):2493-2503.