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Characteristics of living things
1. 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
3. 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
4. Acquire and use materials and energy from the environment
Convert to different forms
Characteristics of living things
7. 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
1. Three domains: Bacteria, Archaea and Eukarya
Domain Eukarya is further divided into Four Kingdoms
Fungi Plantae Animalia Protista
Diversity of life
2. 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
3. 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 principles1. All events are traceable to natural causes.
No intervention of “supernatural forces” that do not act consistently with natural laws.
2. Natural laws apply throughout space and time. Example: Gravitational laws are the same throughout
the universe and throughout time.
3. People perceive natural events in similar ways. Allows different people to compare results of their
experiments.
The scientific method (idealized)
1. Observations
2. Hypothesis Explanation for observed phenomena that is testable, and
thus falsifiable. Leads to one or more predictions that can be tested
3. Experiments Controlled observations that test specific predictions
4. 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!