1. 1 Evolution, the Themes of Biology, and Scientific Inquiry
Lecture Presentation by Nicole Tunbridge and
Kathleen Fitzpatrick

2. Inquiring About Life
An organism’s adaptations to its environment are the result of evolution
For example, the seeds of the dandelion are moved by wind due to their parachute-like structures

3. Figure 1.1a
Figure 1.1a How is the dandelion adapted to its environment? (part 1: dandelion seeds)

4. Biology is the scientific study of life
Biologists ask questions such as
How does a single cell develop into an organism?
How does the human mind work?
How do living things interact in communities?
Life defies a simple, one-sentence definition
Life is recognized by what living things do
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5. Response to the environment
Figure 1.2
Order
Regulation
Reproduction
Evolutionary adaptation
Figure 1.2 Some properties of life
Energy processing
Response to the environment
Growth and development

6. The study of life reveals 5 common themes
New properties emerge at successive levels of biological organization
Life’s processes involve the expression and transmission of genetic information
Life requires the transfer and transformation of energy and matter
Interactions are important in biological systems
Evolution continues to transform life on Earth

7. 6 Organs and Organ Systems 2 Ecosystems
Figure 1.3
7 Tissues
1 The Biosphere
6 Organs and Organ Systems 2
Ecosystems 10
Mole- cules 3
Communities 8
Cells 5
Organisms
Figure 1.3 Exploring levels of biological organization
9 Organelles
4 Populations

8. Emergent Properties
Emergent properties result from the arrangement and interaction of parts within a system
Emergent properties characterize nonbiological entities as well
For example, a functioning bicycle emerges only when all of the necessary parts connect in the correct way

9. Reductionism is the reduction of complex systems to simpler components that are more manageable to study
For example, studying the molecular structure of DNA helps us to understand the chemical basis of inheritance

10. Structure and Function
At each level of the biological hierarchy we find a correlation between structure and function

11. Nucleus (membrane- enclosed)
Figure 1.4
Prokaryotic cell
DNA (no nucleus)
Eukaryotic cell
Membrane
Membrane
Cytoplasm
Figure 1.4 Contrasting eukaryotic and prokaryotic cells in size and complexity
Nucleus (membrane- enclosed)
Membrane- enclosed organelles
DNA (throughout nucleus)
1 µm

12. Figure 1.5
25 µm
Figure 1.5 A lung cell from a newt divides into two smaller cells that will grow and divide again

13. DNA, the Genetic Material
Each chromosome has one long DNA molecule with hundreds or thousands of genes
Genes encode information for building the molecules synthesized within the cell
Genes are the units of inheritance
DNA controls the development and maintenance of organisms

14. Fertilized egg with DNA from both parents
Figure 1.6
Nuclei containing DNA
Sperm cell
Egg cell
Fertilized egg with DNA from both parents
Figure 1.6 Inherited DNA directs development of an organism
Embryo’s cells with copies of inherited DNA
Offspring with traits inherited from both parents

15. Nucleus DNA Nucleotide Cell A C T A T A C C G T A G T A
Figure 1.7 A
Nucleus C
DNA
Nucleotide T A
Cell T A C C G T
Figure 1.7 DNA: The genetic material A G T A
(a) DNA double helix
(b) Single strand of DNA

16. Genes control protein production indirectly
DNA is transcribed into RNA, which is then translated into a protein
Gene expression is the process of converting information from gene to cellular product

17. (b) How do lens cells make crystallin proteins? Crystallin gene
Figure 1.8
(b) How do lens cells make crystallin proteins?
Crystallin gene
(a) Lens cells are tightly packed with transparent proteins called crystallin.
Lens cell
A C C A A A C C G A G T
DNA
T G G T T T G G C T C A
TRANSCRIPTION
mRNA
U G G U U U G G C U C A
TRANSLATION
Chain of amino acids
Figure 1.8 Gene expression: The transfer of information from a gene results in a functional protein
PROTEIN FOLDING
Protein
Crystallin protein

18. Theme: Life Requires the Transfer and Transformation of Energy and Matter
The input of energy from the sun and the transformation of energy from one form to another make life possible
When organisms use energy to perform work, some energy is lost to the surroundings as heat
As a result, energy flows through an ecosystem, usually entering as light and exiting as heat

19. Light energy Chemical energy Chemicals
Figure 1.9
ENERGY FLOW
Chemicals pass to organisms that eat the plants.
Light energy
Chemical energy
Heat
Plants take up chemicals from the soil and air.
Figure 1.9 Energy flow and chemical cycling
Decomposers return chemicals to the soil.
Chemicals

20. Theme: From Ecosystems to Molecules, Interactions Are Important in Biological Systems
Interactions between the components of the system ensure smooth integration of all the parts
This holds true equally well for components of an ecosystem and the molecules in a cell

21. Leaves absorb light energy from the sun.
Figure 1.10
Sunlight
Leaves absorb light energy from the sun.
Leaves take in carbon dioxide from the air and release oxygen.
CO2 O2
Leaves fall to the ground and are decomposed by organisms that return minerals to the soil.
Figure 1.10 Interactions of an African acacia tree with other organisms and the physical environment
Water and minerals in the soil are taken up by the tree through its roots.
Animals eat leaves and fruit from the tree, returning nutrients and minerals to the soil in their waste products.

22. STIMULUS: High blood glucose level
Figure 1.11
STIMULUS: High blood glucose level
Insulin-producing cell in pancreas
Insulin
Circulation throughout body via blood
Negative feedback
Liver and muscle cells
Figure 1.11 Feedback regulation
RESPONSE: Glucose uptake by liver and muscle cells

23. Animation: Negative Feedback

24. Animation: Positive Feedback

25. In feedback regulation the output, or product of a process, regulates that very process
The most common form of regulation in living organisms is negative feedback, in which the response reduces the initial stimulus
Feedback is a regulatory motif common to life at all levels

26. Concept 1.2: The Core Theme: Evolution accounts for the unity and diversity of life
“Nothing in biology makes sense except in the light of evolution”—Theodosius Dobzhansky
Evolutionary mechanisms account for the unity and diversity of all species on Earth

27. Figure 1.12
Ursus americanus
SPECIES GENUS FAMILY ORDER CLASS PHYLUM KINGDOM DOMAIN
Ursus
Ursidae
Carnivora
Mammalia
Figure 1.12 Classifying life
Chordata
Animalia
Eukarya

28. Figure 1.16
Figure 1.16 Charles Darwin as a young man

29. Darwin observed that
Individuals in a population vary in their traits, many of which are heritable
More offspring are produced than survive, and competition is inevitable
Species generally suit their environment

30. Evolution occurs as the unequal reproductive success of individuals
Darwin inferred that
Individuals that are best suited to their environment are more likely to survive and reproduce
Over time, more individuals in a population will have the advantageous traits
Evolution occurs as the unequal reproductive success of individuals
Natural Selection

31. Population with varied inherited traits
Figure 1
Population with varied inherited traits 2
Elimination of individuals with certain traits 3
Reproduction of survivors 4
Increasing frequency of traits that enhance survival
Figure Natural selection (step 4)

32. The Tree of Life
“Unity in diversity” arises from “descent with modification”
For example, the forelimb of the bat, human, and horse and the whale flipper all share a common skeletal architecture
Fossils provide additional evidence of anatomical unity from descent with modification

33. Concept 1.3: In studying nature, scientists make observations and form and test hypotheses
The word science is derived from Latin and means “to know”
Inquiry is the search for information and explanations of natural phenomena
The scientific process includes making observations, forming logical hypotheses, and testing them

34. Making Observations
Biologists describe natural structures and processes
This approach is based on observation and the analysis of data
Recorded observations are called data
Qualitative data often take the form of recorded descriptions
Quantitative data are generally expressed as numerical measurement, organized into tables and graphs

35. Observation: Flashlight doesn’t work.
Figure 1.22
Observation: Flashlight doesn’t work.
Question: Why doesn’t the flashlight work?
Hypothesis #1: Batteries are dead.
Hypothesis #2: Bulb is burnt out.
Prediction: Replacing batteries will fix problem.
Prediction: Replacing bulb will fix problem.
Figure 1.22 A simplified view of the scientific process
Test of prediction: Replace batteries.
Test of prediction: Replace bulb.
Result: Flashlight doesn’t work. Hypothesis is contradicted.
Result: Flashlight works. Hypothesis is supported.