On the islands of Hawaii, approximately 800 species of fruit flies have evolved from just one ancestral species in the 8 million or so years since that ancestor arrived. The heads, forelegs, wings, and mouthparts of different species all look and function very differently. These fruit flies are found nowhere else in the world and live all over the islands, from sea-level rainforests to higher altitude meadows. How could so many species have evolved from a single ancestral fruit fly species?

When you run, you begin to breathe heavier and faster. your heart beats more quickly, bringing more oxygen to your cells. which organ systems are working together here?

Female luna moths (actias luna) attract males by emitting chemical signals that spread through the air. a male hundreds of meters away can detect these molecules and fly toward their source. the sensory organs responsible for this behavior are the comblike antennae visible in the photograph shown here. each filament of an antenna is equipped with thousands of receptor cells that detect the sex attractant. based on what you learned in this chapter, propose a hypothesis to account for the ability of the male moth to detect a specific molecule in the presence of many other molecules in the air. what predictions does your hypothesis make? design an experiment to test one of these predictions.

Which state of matter has the following physical properties: ~ takes the shape of the container it is in ~ takes the volume of the container it is in ~ low density. answer is gas