Topic choices: A sample of potential traits for this case study. Many phenotypic traits could be used in this case study. The trait should be fairly unique and distinct enough to allow students to clearly define the phenotype. It is important that there are published studies to provide enough information for the students to develop some conclusions.
| Trait . | Description . |
|---|---|
| Rattlesnake rattle | One group of pit vipers has developed a modified tail that makes noise. |
| Siblicide | Booby (blue-footed and Nazca) chicks will kill their younger brothers and sisters. How can this be an advantage? |
| Human speech | One of the things that really sets us apart. |
| Paedomorphosis in salamanders | Sometimes adult tiger salamanders do not turn into terrestrial adults but stay in their larval form. |
| Alternative mating strategies in male sunfish | Some males are territorial while others use sneaky strategies to mate. |
| External testes in some mammals | Most vertebrates have internal testes. However, in some mammal species, the testes move out of the body during development. |
| Altruism in humans | Why do some people risk their lives to help others? |
| Deciduous leaves | Oaks (for example) occur in both the temperate and tropical regions. Here they drop their leaves all at the same time. Is “fall” adaptive? |
| Flower color | We mostly think about plants as being green. However, the reproductive organs of many (flowers) are very brightly colored. |
| Armor in male stickleback fish | These little fish, found in both salt water and fresh water, are covered in armor-like plates and have spines that stick out. |
| Feathers | One of the characteristics associated with birds and their relatively unique ability to fly are feathers. |
| Trait . | Description . |
|---|---|
| Rattlesnake rattle | One group of pit vipers has developed a modified tail that makes noise. |
| Siblicide | Booby (blue-footed and Nazca) chicks will kill their younger brothers and sisters. How can this be an advantage? |
| Human speech | One of the things that really sets us apart. |
| Paedomorphosis in salamanders | Sometimes adult tiger salamanders do not turn into terrestrial adults but stay in their larval form. |
| Alternative mating strategies in male sunfish | Some males are territorial while others use sneaky strategies to mate. |
| External testes in some mammals | Most vertebrates have internal testes. However, in some mammal species, the testes move out of the body during development. |
| Altruism in humans | Why do some people risk their lives to help others? |
| Deciduous leaves | Oaks (for example) occur in both the temperate and tropical regions. Here they drop their leaves all at the same time. Is “fall” adaptive? |
| Flower color | We mostly think about plants as being green. However, the reproductive organs of many (flowers) are very brightly colored. |
| Armor in male stickleback fish | These little fish, found in both salt water and fresh water, are covered in armor-like plates and have spines that stick out. |
| Feathers | One of the characteristics associated with birds and their relatively unique ability to fly are feathers. |