Biology in the 21st century

Scientists use observations and data to form and test

• Constants

• Hypothesis

• Theories

• Conclusion

During an experiment, which factor is observed and measured.

• Control variable

• Constant variable

• Independent variable

• Dependent variable

At which stage of scientific thinking are scientists most likely to consider the data and conclusions of other scientists to propose new experiments?

• Observing

• Testing hypothesis

• Analyze data

• Forming a hypothesis

Which phrase best describes scientific theories?

• Explain few observations

• Serve as speculation

• Are never proven

• Cannot be replaced

What is the name given for genetic changes in living things over time?

• Adaptation

• Homeostasis

• Evolution

• Negative feedback

Organisms rely on both negative feedback processes and behavior to maintain

• Homeostasis

• Adaptation

• Ecosystem

• Evolution

In the experiment outlined in the table, three identical tomato seedlings are planted in three identical pots, placed in the same location, and watered on identical schedules. According to the table in Figure 1.3, what conditions differ for each seedling?

Identify each of the following as independent variable, dependent variable, or constant: type of soil used, type of seedling used, and height of plant.

Figure 1.4 shows a small sample of different species of finches that evolved across the Galápagos Islands. One difference among the finches is the size and shape of their beaks, which changed over a long period of time in response to their different environments. What term best describes the differences in beak size and shape?

An organism that makes its own food is called a

• Producer

• Consumer

• Heterotroph

• Chlorophyll