1. Invitation to Biology Chapter 1
Biology Concepts and Applications, Eight Edition, by Starr, Evers, Starr. Brooks/Cole, Cengage Learning 2011.
Biology, Ninth Edition, by Solomon, Berg, Martin. Brooks/Cole, Cengage Learning 2011.

2. 1.1 Life’s Levels of Organization
Nature has levels of organization
Unique properties emerge at successively higher levels
Atoms are organized into molecules
In multicelled species, cells are organized into tissues, organs, and organ systems
All organisms consist of one or more cells

3. Organization of Groups of Organisms
Population
All individuals of one species in a specific area
Community
All populations in a specific area
Ecosystem
A community interacting with its environment
Biosphere
All regions of Earth that hold life
Land, water, and atmosphere

4. Levels of Organization

5. Levels of Organization

6. KEY CONCEPTS: LEVELS OF ORGANIZATION
We study the world of life at different levels of organization, from atoms and molecules to the biosphere
“Life” emerges at the level of cells

7. 1.2 Overview of Life’s Unity
Organisms require energy and materials to sustain their organization and activities
Nutrients are required for growth and survival
Producers make their own food
Consumers eat other organisms
Ecosystems also depend on continuous energy input
There is a one-way flow of energy through ecosystems
Organisms can neither create energy or use it with complete efficiency
During every energy transaction, some energy disperses into the environment as heat

8. The Producers
Plants, algae, and some bacteria are producers (autotrophs) that produce their own food from simple raw materials
Most producers use sunlight as energy for photosynthesis, which transforms light energy into chemical energy stored in chemical bonds of food molecules
Photosynthesis synthesizes food molecules such as glucose (sugar) from carbon dioxide and water, and releases oxygen:
carbon dioxide + water + light → glucose + oxygen

9. carbon dioxide + water + energy
The Consumers
Animals are consumers (heterotrophs) that obtain energy by breaking down food molecules produced in photosynthesis
Primary consumers eat producers; secondary consumers eat primary consumers
Chemical bonds are broken in the process of cellular respiration, and stored energy is made available:
glucose + oxygen →
carbon dioxide + water + energy

10. The Decomposers
Most bacteria and fungi are decomposers, heterotrophs that obtain nutrients by breaking down nonliving organic material such as wastes, dead leaves and branches, and bodies of dead organisms
In the process of obtaining energy, decomposers make the components of these materials available for reuse

11. Energy Flow Within and Among Organisms

12. Ecosystem: Energy Flow and Material Cycling

13. Overview of Life’s Unity
Organisms sense change
Receptors respond to stimulation
Responses keep internal conditions within ranges that cells can tolerate (homeostasis)

14. Response to Stimulus

15. Overview of Life’s Unity
Organisms grow and reproduce
Based on information encoded in DNA
Inheritance transmits DNA from parents to offspring through reproduction mechanisms
Development transforms first cell into an adult

16. Organisms Grow and Develop
Biological growth involves an increase in size of individual cells of an organism, in number of cells, or in both
Some organisms (e.g. trees) grow throughout their lives
Many animals have a growth period that ends at adult size
Development includes all changes during an organism’s life
Example: A human develops from a fertilized egg into a multicellular organism with structures and body form adapted to specific functions

17. Development

18. Organisms Regulate Their Metabolic Processes
Metabolism includes all chemical activities that take place in an organism, including chemical reactions essential to nutrition, growth and repair, and conversion of energy
Homeostatic mechanisms carefully regulate metabolic processes to maintain an appropriate, balanced internal environment (homeostasis)
Example: Regulation of blood sugar (glucose)

19. Instructions Assemble Materials

20. KEY CONCEPTS: LIFE’S UNDERLYING UNITY
All organisms are alike in key respects:
Consist of one or more cells
Live through inputs of energy and raw materials
Sense and respond to changes in their external and internal environments
Cells contain DNA (molecule that offspring inherit from parents; encodes information necessary for growth, survival, and reproduction)

21. 1.3 So Much Unity, So Many Species
The world of life, past and present, shows great diversity
Classification systems organize species in ever more inclusive groups
Taxonomy, is the science of naming and classifying organisms

22. Genus and Species Species: One kind of organism
A species is a group of organisms with similar structure, function, and behavior

23. Binomial System
The binomial system of nomenclature is used to name each species, it is called such because each species has a two-part name
The first part of the name is the genus
Closely related species are grouped into a genus (genera)
The second part, the specific epithet, designates a particular species in that genus
Example: The domestic dog, Canis familiaris (or C. familiaris), and timber wolf, Canis lupus (C. lupus), are in the same genus

24. Taxonomic Classification is Hierarchical
Related genera are grouped in a family
Families are grouped into orders, orders into classes, and classes into phyla (phylum)
Phyla are assigned to kingdoms, and kingdoms are grouped in domains
Each level is a taxon (taxa)

25. Classification of the Cat, Human, and White Oak Tree
Table 1-1, p. 11

26. DOMAIN Eukarya KINGDOM Animalia PHYLUM Chordata CLASS Mammalia ORDER
Figure 1.10: Classification of the chimpanzee (Pan troglodytes).
Primates
FAMILY
Pongidae
GENUS
Pan
SPECIES
Pan troglodytes
Fig. 1-10, p. 12

27. Domains Current classification groups all species into three domains
Bacteria (single-celled prokaryotes)
Archaea (single-celled prokaryotes)
Eukarya (protists, plants, fungi, and animals)

28. Life’s Three Domains

29. Figure 1.11: A survey of the three domains of life.
Domain Bacteria
(a) The large,
rod-shaped bacterium Bacillus anthracis, a member of domain Bacteria, causes anthrax, a disease of cattle and sheep that can infect humans.
Bacteria
Common ancestor
of all organisms
Domain Archaea
Archaea
(b) These
archaea (Methanosarcina mazei), members
of the domain Archaea, produce methane.
Domain Eukarya
(c) These unicellular protozoa (Tetrahymena) are classified in one of the protist groups.
(d) Plants include many beautiful and diverse forms, such as the lady’s slipper (Phragmipedium caricinum).
(e) Among the fiercest animals, lions (Panthera leo) are also among the
most sociable. The largest of the big cats, lions live in prides (groups).
(f) Mushrooms,
such as these
fly agaric mushrooms (Amanita muscaria), are fungi. The fly agaric is poisonous and causes delirium, raving, and profuse sweating when ingested.
Protists
Plants
Animals
Fungi
Figure 1.11: A survey of the three domains of life.
Biologists assign organisms to three domains and to several kingdoms and other groups. The protists do not form a clade and are no longer considered a kingdom. They are assigned to five “supergroups” (not shown).

30. KEY CONCEPTS: LIFE’S DIVERSITY
The world of life shows great diversity
Many millions of kinds of organisms (species) have appeared and disappeared over time
Each species is unique in at least one trait—in some aspect of its body form or behavior

31. 1.4 An Evolutionary View of Diversity
Life’s diversity arises from mutations
Changes in molecules of DNA which offspring inherit from their parents
In natural populations, mutations introduce variation in heritable traits among individuals

32. Variation in Heritable Traits
Some trait forms are more adaptive than others
Bearers are more likely to survive and reproduce
Over generations, adaptive forms of traits tend to become more common in a population
Less adaptive forms of the same traits become less common or are lost

33. Evolution Populations evolve Evolution
Traits that help characterize a population (and a species) can change over generations
Evolution
Change which occurs in a line of descent

34. Selection Natural selection Artificial selection
In natural populations
Differential survival and reproduction among individuals that vary in one or more heritable traits
Artificial selection
Breeding of captive populations
Traits selected are not necessarily adaptive

35. KEY CONCEPTS: EXPLAINING UNITY IN DIVERSITY
Theories of evolution (especially a theory of evolution by natural selection) help explain why life shows both unity and diversity
Evolutionary theories guide research in all fields of biology

36. 1.5 Critical Thinking and Science
Critical thinking is a self-directed act of judging the quality of information as one learns
Science is a way of looking at the natural world
Helps minimize bias in judgments
Focuses on testable ideas about observable aspects of nature

37. Evidence-Based Thinking

38. 1.6 How Science Works Researchers generally
Observe something in nature
Form hypotheses (testable assumptions) about it
Make predictions about what might occur if the hypothesis is not wrong
Test their predictions by observations, experiments, or both

39. Experiments Tests used to support or falsify a prediction
Variable characteristic is measured and changed
Dependent variable: is presumably affected by the independent variable (ex. Severity of hangover)
Independent variable: controlled by the experimenter in order to explore its relationship with the dependent variable (ex. Prophylactic treatment for a hangover)
In the control group, variables do not change

40. A Scientific Approach

41. Scientific Theory A well-tested hypothesis
Explains a broad range of observations
Can be used to make useful predictions about other phenomena
A good hypothesis has three characteristics:
It is reasonably consistent with well-established facts
It is capable of being tested; and test results should be repeatable by independent observers
It is falsifiable (can be proven false)
Opinion and belief are not scientific theory !!!!

42. A Falsifiable Hypothesis Can Be Tested
A well-stated hypothesis can be tested
If no evidence is found to support it, the hypothesis is rejected
The hypothesis can be shown to be false
A hypothesis can be supported by data, but it can’t really be proven true

43. Some Scientific Theories
Atomic Theory
All Substances consist of atoms
Big Bang
The universe originated with an explosion and continues to expand
Cell Theory
All organisms consist of one or more cells, the cell is the basic unit of life, and all cells arise from existing cells
Evolution
Change occurs in the inherited traits of a population over generations
Global Warming
Human activities are causing Earth’s average temperature to increase

44. 1.7 The Power of Experiments
Biological systems have many variables
Experiments simplify observations of nature
Focus on cause, effect, or function of one variable at a time
Researchers design experiments to minimize potential bias in interpreting results

45. A Controlled Experiment

46. Hypothesis Prediction Experiment Control Group Experimental Group
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.
Experiment
Control Group
Experimental Group
Eats regular
potato chips
Eats Olestra
potato chips
Results
93 of 529 people
get cramps later
(17.6%)
89 of 563 people
get cramps later
(15.8%)
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. 1.11, p. 14

47. Butterflies and Birds: A Behavioral Experiment
Wing Spots
Wing Sound
Total Number of Butterflies
Number Eaten
Number Survived
Spots
Sound 9
9 (100%)
No Spots 10 5
5 (50%)
No Sound 8
8 (100%)
2 (20%)

48. Stepped Art a Wing spots painted out d Wings painted but spots visible
e Wings
cut but not
silenced
f Wings painted but
spots visible; wings
cut but not silenced
b Wing spots
visible; wings
silenced
c Wing spots
painted out;
wings silenced
Stepped Art
Fig. 1-14, p. 18

49. 1.8 Sampling Error in Experiments
Difference between results derived from testing an entire group and results derived form testing a subset of the group.
Small sample size increases the likelihood of sampling error in experiments
In such cases, a subset may be tested that is not representative of the whole
1.8 Sampling Error in Experiments

50. KEY CONCEPTS: HOW WE KNOW
Biologists make systematic observations, predictions, and tests in the laboratory and field
They report their results so others may repeat their work and check their reasoning

51. Animation: Building blocks of life
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52. Animation: Insect development
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53. Animation: Life's diversity
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54. Animation: Life's levels of organization
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55. Animation: One-way energy flow and materials cycling
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56. Animation: Sampling error
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57. Animation: Three domains
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