1. Human Biology, Science, and Society1
Human Biology, Science, and Society 1

2. The Characteristics of Life
What is SCIENCE?
What is NATURE?
What is BIOLOGY?

3. The Characteristics of Life
Living things
Have a different molecular structure than nonliving things
Require energy and raw materials
Are composed of cells
Maintain homeostasis
Respond to their external environment
Grow and reproduce
Populations of living things evolve 3

4. Living Things Are Grouped According to Characteristics
Protista
(Protozoans
and algae)
Animalia
(Animals)
Fungi
(Fungi)
Plantae
(Plants)
Kingdoms
(Bacteria;
Single cells,
no nucleus)
(Bacteria;
primitive single
cells, no nucleus,
live in extreme
conditions)
BACTERIA
ARCHAEA
EUKARYA
DOMAINS
Figure 1.4 Domains and kingdoms.
Earliest Organisms 4

5. Fundamental Criteria Used for Classification
Presence or absence of a nucleus
Domain Bacteria and Domain Archaea lack a membrane-bound nucleus
Domain Eukarya have a membrane-bound nucleus
Number of cells
Unicellular
Multicellular
Type of metabolism

6. Domain Eukarya
Protista: unicellular and simple multicellular, eukaryotic (protozoa, algae, slime molds)
Plantae: multicellular, eukaryotic, photosynthetic
Animalia: multicellular, eukaryotic, heterotrophic
Fungi: (molds, yeasts, mushrooms) eukaryotic, decomposers 6

7. Classification of Humans (Homo sapiens)
Domain: Eukarya
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Primates
Family: Hominidae
Genus: Homo
Species: sapiens

8. Living Things Are Grouped According to Characteristics
Smallest unit of classification system is species
One or more populations of organisms
Similar physical and functional characteristics
Can interbreed and produce fertile offspring
Second smallest unit is genus
All living human beings belong to the same genus and species
Homo sapiens

9. Defining Features of Humans
Bipedalism: able to stand upright and walk on two legs
Opposable thumbs: able to grasp objects between thumb and tips of fingers
Large brain: relative to body size
Capacity for language: both spoken and written 9

10. Human Chimpanzee Figure 1.5
Figure 1.5 How humans and chimpanzees hold small objects.
Human
Chimpanzee 10

11. Human Biology Can Be Studied On Any Level of Biological Organization
Atom and molecule
Cell
Tissue
Organ
Organ system
Organism
Population
Community
Ecosystem
Biosphere 11

12. Organism Organ Population system Molecule Atom Organ Tissue Cell
Figure 1.7
Organism
Organ
system
Population
Molecule
Atom
Organ
Tissue
Cell
Community
Figure 1.7 Levels of organization in human biology.
Ecosystem
Biosphere 12

13. Science Is Both a Body of Knowledge and a Process
Science is the study of the natural world
Science is two things
1. Knowledge about the natural world
2. The process used to acquire knowledge
Called the scientific method

14. The Scientific Method Science Process & Information Scientific Method
What is the purpose of the scientific method?
Science
Process & Information
Scientific
Method
Scientific knowledge 

15. The Scientific Method Is a Process for Testing Ideas
Steps in the scientific method
Observe and generalize
Formulate a hypothesis
Make a testable prediction
Experiment or observe
Modify the hypothesis as necessary and repeat 15

16. Case of the faulty flashlight…
Observation:
Flashlight does not work!
Question:
Why isn’t the flashlight working?
Hypothesis:
The batteries are dead.
Prediction:
Replacing batteries will fix it.
Results:
It works (or does not work) with new batteries
Conclusion:
Test does (or does not) falsify the hypothesis

17. Figure 1.8 2 5 5 4 4 1
Formulate a
hypothesis
Modify
hypothesis as
necessary
and repeat
steps
3 and 4
Modify
hypothesis as
necessary
and repeat
steps
3 and 4
Direction of
increasing
confidence in
hypothesis
Experiment or
observe
Experiment or
observe
Observe
and
generalize 3
Figure 1.8 The scientific method.
Make a testable
prediction 3
Make a testable
prediction 3
Make a testable
prediction 17

18. The Scientific Method Is a Process for Testing Ideas
Observe and generalize
Inductive reasoning: make generalizations based on observations about the world
Example:
Observation: “Every winter in the past was colder than the preceding summer.”
Generalization: “Winter will always be colder than summer.”

19. The Scientific Method Is a Process for Testing Ideas
Formulate a hypothesis
A hypothesis is a tentative statement about the natural world

20. The Scientific Method Is a Process for Testing Ideas
Make a testable prediction
Hypotheses should be tested under many different conditions
Testable predictions
Should be based on the hypothesis
Should employ deductive reasoning
Are often in the form of “if…then” statements
Should be specific in order to be testable
Experiment and observe..

21. Yes No Select a large number of appropriate subjects.
Figure 1.9
Select a large number
of appropriate subjects.
Randomly divide the
subjects into two groups.
Group 1
Group 2
Treat the groups equally
in all ways but one.
Experimental group:
receives treatment
Control group:
receives placebo
Observe or make
measurements.
Figure 1.9 The steps in a controlled experiment.
Are blood pressures lower
In the experimental group?
Compare results.
Yes No
Hypothesis received
support.
Modify hypothesis to
fit the new findings. 21

22. The Scientific Method Is a Process for Testing Ideas
Modify the hypothesis as necessary and repeat Steps three and four
If prediction is false, the hypothesis must be modified.
If the prediction is true, only one small part of the hypothesis has been tested. Further testing required.
Hypotheses cannot be proved true, only supported or disproved.

23. Hypothesis Becomes a Theory
For a hypothesis to become a theory it must:
be broad
be extensively tested
be supported over time
explain a broad range of facts
have a high degree of reliability
Theories may be refuted in the future 23

24. The Scientific Method For a hypothesis to become a theory it must be…
broad
extensively tested
supported over time
Explain a broad range of facts
Have a high degree of reliability
Theories may be refuted in the future

25. Learning to be a Critical Thinker
What makes a good OBSERVER or SCIENTIST?
Become a skeptic; a questioning attitude
Appreciate the value of statistics; numerical data
Learn to read graphs; display data
Distinguish anecdotes from scientific evidence
Separate facts from conclusions
Fact is a verifiable piece of information
Conclusion is a judgment based on facts
Understand the differences between correlation and causation
Correlation does not imply causation

26. Why do we spend billions of dollar on research?
Science in Society
Why do we spend billions of dollar on research?
Science improves technology and the human condition
Science helps us to make informed choices
Science has limits!!!