There are two approaches to explaining phenomena in biology (especially used in ecology and behavior): Proximate and ultimate explanations.

Proximate explanations focus on how a phenomena works (what controls the phenomena as it is now seen). The goal is to understand the underlying mechanisms. How does a trait work? Proximate questions do not require an evolutionary explanation.

• How are sonar clicks produced by bats? How is the ear modified to perceive and use these signals?
• How does a bird give parental care.
• How does a bird learn it's song?
• How does a bird ant?
• How is it that we crave sweet/fatty foods?
• Reworded How question: Why do we have sex?
• How is it that religion is universal across all cultures?

Ultimate explanations focus on why a trait exists. Ultimate questions require an evolutionary explanation. Ultimate explanations often look at the "un-economy" of nature.

• Why do bats have sonar? What is the evolutionary origin of sonar?
• Why does a bird give parental care?
• Why does a bird learn a song?
• Why does a bird perform anting behavior?
• Why do we crave sweet/fatty foods when they are bad for us?
• Why do we have sex?
• Why is religion universal across all cultures?