exam 1 scientific method

What are the steps in the scientific method, in order?

• Make observations

• Formulate question

• Develop hypothesis

• Make predictions

• Design study (observational or experimental)

• Perform study and collect data

• Analyze data

• Interpret data (are predictions correct?)

• Make conclusions (is hypothesis supported?)

• Communicate results

What is a hypothesis?

An explanation of a phenomenon or pattern. It is a possible answer to the question, based on observations and/or published literature

State three main hypotheses for why zebras have stripes.

• Crypsis (camouflage against predators)

• Antiparasite (avoidance of biting flies)

• Thermoregulation (cooling effect)

Write an example of a scientific observation (not an inference).

The zebra pelt shows alternating black and white stripes on the body and legs

Give predictions for each zebra-stripe hypothesis.

Crypsis → zebras are more cryptic than sympatric non-striped herbivores; Antiparasite → biting flies are more attracted to uniform colors than to black-and-white stripes; Thermoregulation → zebras have cooler body temperatures than sympatric non-striped herbivores.

How would you design a study to test whether stripes deter biting flies?

Use paired traps/objects (e.g., inflated balls or pelts) covered with zebra vs non-striped pelts/colors, count tabanids/flies trapped per pair, compare counts.

How do you interpret a graph (general steps)?

Identify axes (x = independent/predictor, y = dependent/response), identify graph type (bar, boxplot, line, scatter), look for patterns (higher/lower/similar; increase/decrease/no change), compare groups to predictions.

Interpret study results: Caro et al. (zebra hypotheses) — crypsis, biting flies, thermoregulation. Which were supported?

Crypsis: prediction NOT supported; Biting flies: prediction SUPPORTED (fewer flies on zebra patterns); Thermoregulation: prediction NOT supported. (Conclusion from slides: biting flies are the evolutionary driver; aposematic deterrence by hyenas may be secondary.)

Explain why zebras have stripes (slide conclusion).

Stripes help zebras avoid biting flies, reducing parasite load and energy spent swatting flies, which increases survival and reproduction; biting flies best predict stripe presence across equids.