1. Chapter 1 General Biology I
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2. The Science of Life Biology unifies much of natural science
Life defies simple definition
Living systems are the most complex chemical systems on Earth
Life is constrained by the properties of chemistry and physics
Science is becoming more interdisciplinary
Combining multiple fields 2

3. The Science of Life 7 characteristics of all living organisms
Cellular organization
Ordered complexity
Sensitivity
Growth, development, and reproduction
Energy utilization
Homeostasis
Evolutionary adaptation 3

4. The Science of Life Living systems show hierarchical organization
Cellular level
Organismal level
Populational level
Ecosystem level
Biosphere 4

5. The Science of Life Living systems show hierarchical organization
Cellular level
Atoms, molecules, organelles, cells
Cell is the basic unit of life
Organismal level
Tissues, organs, organ systems
Populational level
Population, community
Ecosystem level
Biosphere
All the livable space on the planet
99% of it is in the ocean!!! 5

7. PM: fix centering of col. Headings?

8. Populational Level 8 POPULATIONAL LEVEL Population Species Community
Ecosystem
Biosphere
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9. The Science of Life
As you move up the hierarchy, novel properties emerge
Result from interaction of components
Cannot be deduced by looking at parts themselves
“Life” is an emergent property
Populational correct as set? 9

10. The Nature of Science
Science aims to understand the natural world through observation and reasoning
Science begins with observations, therefore, much of science is purely descriptive
Classification of all life on Earth
Human genome sequencing 10

11. The Nature of Science
Science uses both deductive and inductive reasoning
Deductive reasoning uses general principles to make specific predictions
If all mammals have hair and you find an animal that doesn’t, you might say that the animal you are looking at is not a mammal
Used to test the validity of general ideas in all branches of knowledge
Inductive reasoning uses specific observations to develop general conclusions
If poodles have hair and terriers have hair, then you might generalize that all dogs have hair 11

12. The Nature of Science
Scientists use a systematic approach to gain understanding of the natural world = Scientific Method
Observation
Hypothesis formation
Prediction
Experimentation
Conclusion 12

14. The Nature of Science
A hypothesis is a possible explanation for an observation
Not just an “educated guess”
A hypothesis
Must be tested to determine its validity
Is often tested in many different ways
Allows for predictions to be made
Iterative
Hypotheses can be changed and refined with new data 14

15. The Nature of Science Experiment Tests the hypothesis
Must be carefully designed to test only one variable at a time
Consists of a test experiment and a control experiment 15

16. The Nature of Science Predictions Hypotheses should make predictions
Predictions provide a way to test the validity of hypotheses
Hypothesis must be rejected if the experiment produces results inconsistent with the predictions
The more experimentally supported predictions a hypothesis makes, the more valid the hypothesis 16

18. The Nature of Science Philosophical approaches to science Reductionism
To break a complex process down to its simpler parts
For example
Cellular metabolism is very complex, reductionism is looking at one pathway and the function of that enzyme
However, that enzyme may work differently when not isolated from other enzymes and molecules within the cell
Systems biology
Focus on emergent properties that can’t be understood by looking at simpler parts 18

19. The Nature of Science Models in science Way to organize thought
Parts provided by reductionist approach
Model shows how they fit together
Suggest experiments to test the model 19

20. The Nature of Science Scientific theory
Is a body of interconnected concepts
Is supported by much experimental evidence and scientific reasoning
Expresses ideas of which we are most certain
When you say “theory” in science, it is as close to fact that you will get to with the information and technology we have available to us at the time
Compare to general meaning of theory
Different in everyday language, implies a lack of knowledge or a guess 20

21. Darwin and Evolution
Example of how a scientist develops a hypothesis and a theory gains acceptance
Charles Darwin served as naturalist on mapping expedition around coastal South America
30 years of observation and study before publishing On the Origin of Species by Means of Natural Selection 21
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22. Voyage of the HMS Beagle
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British Isles
Western
Isles
EUROPE
ASIA
NORTH
AMERICA
NORTH
PACIFIC
OCEAN
NORTH
ATLANTIC
OCEAN
NORTH
PACIFIC
OCEAN
Canary
Islands
Cape Verde
Islands
Philippine
Islands
Galápagos
Islands
AFRICA
INDIAN
OCEAN
Keeling
Islands
Equator
SOUTH
AMERICA
Ascension
Madagascar
Bahia
Marquesas
St. Helena
Friendly
Islands
Mauritius
Bourbon Island
Valparaiso
Rio de Janeiro
AUSTRALIA
Society
Islands
Sydney
Montevideo
Cape of
Good Hope
Buenos Aires
King George’s
Sound
Port Desire
Hobart
New
Zealand
Straits of Magellan
Falkland
Islands
SOUTH
ATLANTIC
OCEAN
Cape Horn
Tierra del Fuego 22

23. Darwin and Evolution Darwin was not the first to propose evolution
Living things have changed over time
Darwin’s contribution was a mechanism for evolution
He proposed Natural selection 23

24. Darwin and Evolution
On the Beagle, Darwin saw that characteristics of similar species varied from place to place
Galápagos Finches
14 related species differ only slightly
“Descent with modification” or evolution
Woodpecker Finch (Cactospiza pallida)
Large Ground Finch (Geospiza magnirostris)
Cactus Finch (Geospiza scandens) 24
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25. Darwin and Evolution
Darwin studied Thomas Malthus’s An Essay on the Principle of Population
Populations of plants and animals increase geometrically (multiplicative, example x3)
Humans can only increase their food supply arithmetically (additive, example +2)
Populations of species remain constant because death limits population numbers
There are individuals that possess physical, behavioral or other attributes that give them an advantage 25

26. Darwin and Evolution Darwin saw that:
Every organism has the potential to produce more offspring
But, only a limited number survive and reproduce themselves
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geometric progression
arithmetic progression 54
Human Growth is Geometric
Human food production is Arithmetic 18 6 8 2 6 4 26

27. Darwin and Evolution Darwin made an important association:
Individuals with attributes that give them an advantage in their environment are more likely to survive and reproduce
Pass these characteristics on to their offspring
The population will gradually change over time
Darwin called this selection

28. Darwin and Evolution
Evidence supporting Darwin’s theory has only grown
Fossil record
Earth’s age
Mechanism for heredity
Comparative anatomy
Molecular Evidence 28

29. Darwin and Evolution Fossil record Earth’s age
Transitional forms have been found at predicted positions in time
Earth’s age
Earth is very old – 4.5 billion years old 29

30. Darwin and Evolution Mechanism for heredity
Mendel’s laws of inheritance were unknown to Darwin
At time of Darwin there was no concept of “genes” or how heredity worked
Darwin could not completely explain how evolution worked
Now have detailed understanding of heredity 30

31. Darwin and Evolution Comparative anatomy
Vertebrate forelimbs all share the same basic array of bones
Homologous – same evolutionary origin but now differ in structure and function
Analogous – structures of different origin used for the same purpose (butterfly and bird wings) 31

34. Unifying Themes in Biology
Cell theory
All organisms composed of cells
Cells are life’s basic units
All cells come from preexisting cells
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60 µm 34 b.
500 µm
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35. Unifying Themes in Biology
Molecular basis of inheritance
Deoxyribonucleic acid (DNA)
Sequence of 4 nucleotides encode all of a cell’s information – A, T, C, G
Gene – discrete unit of information
Genome – entire set of DNA instructions
Continuity of life depends on faithful copying of DNA into daughter cells 35

36. Unifying Themes in Biology
Structure and function
Study structure to learn function
Know a function – look for that structure in other organisms
Example
Receptor on human cell for insulin known
Find similar molecule in a worm
Might conclude this molecule functions the same in the worm 36

37. Unifying Themes in Biology
Diversity of life arises by evolution
Underlying unity of biochemistry and genetics argues for life from the same origin event
Diversity due to evolutionary change over time
3 domains
Bacteria – single-celled prokaryote, bacteria
Archaea – single-celled prokaryote, includes extremophile bacteria
Eukarya – single-celled or multicellular eukaryote; includes protists, fungi, plants, and animals. 37

38. 38 Plantae Fungi Eukarya Animalia Protista
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Plantae
Fungi
Eukarya
Animalia
Protista
(plantae middle): © David M. Dennis/Animals Animals; (plantae right): © Corbis/Volume 46 RF; (fungi left): © Royalty Free/Corbis; (fungi middle): © Mediscan/Corbis; (fungi right): © PhotoDisc BS/Volume 15 RF; (animalia left): © Royalty-Free/Corbis; (animalia middle): © Tom Brakefield/Corbis; (animalia right): © PhotoDisc/Volume 44 RF; (protista left): © Corbis/Volume 64 RF; (protista middle): © Tom Adams/Visuals Unlimited; (protista right): © Douglas P. Wilson/Frank Lane Picture Agency/Corbis 38

39. Unifying Themes in Biology
Evolutionary conservation
All organisms today descended from a simple creature 3.5 BYA
Some characteristics preserved
Our DNA encodes everything
For example, you need certain enzymes for cellular respiration, those are encoded in your DNA; those same enzymes are used by other organisms for the same process
Conservation reflects that they have a fundamental role 39

40. Unifying Themes in Biology
Cells are information-processing systems
Information in DNA used to direct synthesis of cellular components
Control of gene expression leads to different cells/ tissue types
Cells process environmental information
Glucose levels, presence of hormones
Cells in multicellular organisms must coordinate with each other 40

41. Unifying Themes in Biology
Nonequilibrium state
Living systems are open systems
Constant supply of energy needed
Self-organizing properties at different levels
Emergent properties from collections of molecules, cells, and individuals 41