AdaptationPurpose Tusks Trunk Wide, flat feet Large ears fighting Drinking, bathing Support body weight ?
When scientists want to conduct an investigation, they follow the scientific method. There are 6 steps. Scientists always begin by asking a question (step 1). “Why do African elephants have such large ears?” (What is the purpose of this adaptation?) Better hearing? Intimidate (scare) other males? Attract females? Keep away flies? Stay cool? Something else?
To help narrow down the hypothesis, scientists do background research (step 2). African elephants have no natural predators. Males intimidate with their tusks, not their ears. The average temperature of the African savanna is 70°-113° F. African elephants have no sweat glands. No natural predators Intimidate with their tusks, not their ears The African savanna is extremely hot
Based on this research, scientists construct a hypothesis (step 3). Background Research: Africa is hot; elephants don’t sweat. Inference: Elephants need a way to cool down. Hypothesis: African elephants have large ears to stay cool.
To see if the hypothesis is true, scientists test the hypothesis with a controlled experiment (step 4). Sometimes direct observation is difficult, dangerous, or impossible!
Testing the hypothesis with an experiment Materials needed: African elephant Jeep or other sturdy vehicle Safety equipment (such as a tranquilizer gun) Instrument to measure heat loss What instrument could we use to measure heat loss?
Testing the hypothesis with an experiment Instrument to measure heat loss: infrared camera Infrared (heat-sensing) camera Infrared image of a dog (scary!) Hot Cool
Testing the hypothesis with an experiment What does the infrared video show about the elephant’s ears compared to the rest of its body? Hot Cool
Next, scientists analyze the data. Based on the data, they draw conclusion (step 5). Data: the ears are the coolest part of its body (80°-95° F) Conclusion: the hypothesis was correct. Hot Cool
If the hypothesis is correct, scientists can then report their results to the world (step 6). What if her hypothesis had been incorrect? “Animals use various ways of cooling in hot weather. For example, the surface area of large elephant’s ears serves as a heat radiator and helps them to stay cool. In hot weather, elephants increase the blood supply to the ears and flap them around to lose body heat.” http://www.fpv.umb.sk/kat/kf/Integr ated_Science/SG/Life_science/Elepha nt/index1.htm