Introduction Chapter 1: Sections 1.1, 1.2, 1.3

Characteristics of living things Complex organized structure Organic molecules (carbon framework!) are the key molecules that form this structure for Earth’s organisms. Note the difference between the scientific definition of organic vs. the organic foods movement’s definition!

Characteristics of living things Respond to stimuli from their environment

Characteristics of living things Exhibit homeostasis: Actively maintain a relatively constant internal environment and structure Example: Humans sweat to cool off and maintain a body temperature of 98.6ºF

Characteristics of living things Acquire and use materials and energy from the environment Convert to different forms

Characteristics of living things Growth Reproduction DNA is the molecule of heredity on Earth

Characteristics of living things Have the capacity to evolve Change in the genetic composition, and thus the characteristics, of a population over generations. It is populations, not individuals, that evolve

Diversity of life Three domains: Bacteria, Archaea and Eukarya Domain Eukarya is further divided into Four Kingdoms Fungi Plantae Animalia Protista

Diversity of life Focus: Domains Bacteria & Archaea Single-celled Relatively simple; no nucleus (prokaryotic) No membrane-bound structures Relatively small Differ from each other structurally and biochemically…

Diversity of life Focus: Domain Eukarya All have nuclei and other membrane-bound organelles Generally larger than Bacteria and Archaea We will explore differences among these groups… Protista Animalia Fungi Plantae

What is the science of biology? Or, “Thinking like a scientist” General scientific principles All events are traceable to natural causes. No intervention of “supernatural forces” that do not act consistently with natural laws. Natural laws apply throughout space and time. Example: Gravitational laws are the same throughout the universe and throughout time. People perceive natural events in similar ways. Allows different people to compare results of their experiments.

The scientific method (idealized) Observations Hypothesis Explanation for observed phenomena that is testable, and thus falsifiable. Leads to one or more predictions that can be tested Experiments Controlled observations that test specific predictions Conclusion Did the experimental results support the hypothesis? Did the experimental results disprove the hypothesis?

The scientific method (idealized): An example In the 1600’s, Francesco Redi used the scientific method to challenge the idea that maggots in meat were produced by “spontaneous generation.” Alternate hypothesis: “Maggots in meat are produced by spontaneous generation.”

Conclusions? Original hypothesis (text): Flies produce maggots; keeping flies away will prevent the appearance of maggots. Alternate hypothesis: “Maggots in meat are produced by spontaneous generation.” Did the results support either hypothesis? Did the results falsify either hypothesis? Notice the power of falsification!

Scientific theories Like hypotheses, theories are testable and falsifiable! Theories have been thoroughly tested; much supporting evidence has been found! Developed via inductive reasoning. Many specific observations  general theory.