1. Learning about Human Biology
Chapter 1

2. 1.1 The Characteristics of Life
Focus: Several basic characteristics allow us to distinguish between living things and nonliving objects.

3. The Characteristics of Life
Living things take in energy and materials
Energy: the capacity to do work
Living things sense and respond to changes in the environment
Living things reproduce and grow
Living things consist of one or more cells
Living things maintain homeostasis

4. Humans Take in Energy by Eating Food

5. Cells Are the Basic Units of Life

6. Summary of Life’s Characteristics

7. 1.2 Our Place in the Natural World
Focus: Human beings arose as a distinct group of animals during an evolutionary journey that began billions of years ago.

8. Humans Have Evolved over Time
Evolution – change in the body plan and functioning of organisms through the generations
Began billions of years ago
Continues today
Where do we fit in?
Primates
Vertebrates
Classification of living organisms
Three domains of life
Five kingdoms of life – changing as we speak!

9. Animation: Life’s diversity

10. Humans Are Related to Earth’s Other Organisms

11. Humans Have Some Distinctive Characteristics
Mammalian features
Hair
Mammary glands
Distinctive PRIMATE features
Manual dexterity
Brain
Size
Capacity for sophisticated language and analysis
Development of various social behaviors

12. 1.3 Life’s Organization
Focus: Nature is organized on many levels, starting with nonliving materials and eventually including the whole living world.

13. Life's hierarchy:
Figure 1.5: Animated! An overview of the levels of organization in nature.
Fig. 1-5a, p. 4

14. Life's hierarchy:
Figure 1.5: Animated! An overview of the levels of organization in nature.
Fig. 1-5b, p. 5

15. Animation: Life’s levels of organization

16. Animation: Building blocks of life

17. Organisms Are Connected through the Flow of Energy and Cycling of Materials
Solar energy and photosynthesis
Interconnections among organisms
Producers
Consumers
Decomposers
bacteria and fungi

18. The Flow of Energy and the Cycling of Materials Maintain Nature’s Organization
versus
Cycle!

19. Animation: One-way energy flow and materials cycling

20. 1.4 Using Science to Learn about the Natural World
Focus: Science basically is a way of thinking about the natural world by making and testing predictions they search for evidence that may disprove or support a proposed explanation.

21. Science Is a Systematic Study of Nature
Scientific method
Observe some aspect of nature
Ask a question about the observation or identify a problem to explore
Develop a hypothesis
Make a prediction
Test the prediction
Repeat the tests or develop new ones
Analyze and report the test results and conclusions

22. Scientists Do Research in the Laboratory and in the Field

23. Animation: Sampling error

24. Example Experiment: Hypothesis: Olestra® causes intestinal cramps
Variables
Independent
Dependent
Standardized
Groups
Control
Experimental

25. Example Hypothesis Olestra® causes intestinal cramps. Prediction
People who eat potato chips made with Olestra will be more likely to get intestinal cramps than those who eat potato chips made without Olestra.
Control Group Eats regular potato chips
Experimental Group Eats Olestra
potato chips
Experiment
Example
Results
93 of 529 people
get cramps later (17.6%)
89 of 563 people get cramps later
(15.8%)
Figure 1.8: The Olestra study followed a sequence of steps used in many scientific experiments.
Conclusion
Percentages are about equal. People who eat potato chips made with Olestra are just as likely to get intestinal cramps as those who eat potato chips made without Olestra.
These results do not support the hypothesis.
Fig. 1-8, p. 7

26. Science Never Stops Is more research needed on Olestra?
Olestra reformulated to reduce side effects?

27. Examples of Scientific Theories

28. Animation: An example of the scientific method

29. 1.5 Critical Thinking in Science and Life
Focus: To think critically, we must evaluate information before accepting it.

30. A Guide to Critical Thinking

31. Evaluate the Source of Information
Let credible scientific evidence, not opinions or hearsay, do the convincing
Question credentials
Question motives

32. Evaluate the Content of Information
Fact versus opinion
Cause versus correlation
Ice cream & crime

33. 1.6 Science in Perspective
Focus: A scientific theory explains a large number of observations.

34. What the Word “Theory” Means in Science
Supported by tens of thousands of experiments
May be modified or even rejected upon further investigations
Science is tentative!

35. Science Has Limits
External world is testing ground for scientific views
Natural world only (not supernatural)
Culture and society: NOT a part of science!
Morals
Esthetics
Religious beliefs

36. 1.7 Living in a World of Infectious Disease
Focus: Humans have always lived with countless health threats. Today we are locked in an escalating global battle with bacteria, viruses, parasites, and other pathogens -agents that can cause disease.

37. Black Death

38. Infections Are a Threat Because They Disrupt Homeostasis
Infection – pathogen enters cells or tissues and reproduce
Disease – when the pathogen overwhelms the host’s defense systems
Effect on homeostasis
Major versus minor disruptions

39. What Do Pathogens Look Like?
Bacteria
Viruses
Fungi
Parasitic protists
Parasitic worms

40. A Wide Variety of Pathogens May Live on or in the Human Body

41. Emerging Diseases Present New Challenges
Causative agents of emerging diseases
West Nile virus: encephalitis
SARS virus: severe acute respiratory syndrome
Ebola virus: hemorrhagic fever
Borrelia burgdorferi bacterium: Lyme disease

42. The SARS and Ebola Viruses

43. Antibiotics Are a Double-Edged Sword
Discovered in the 1940s
Organisms that produce antibiotics
natural chemicals that can destroy bacteria
Antibiotic resistance is a major health threat
Caused by abuse or improper use

44. Scientific Method Review

45. Book Companion Site:
Need extra help?
Check it out at home!