1. Biology: Exploring Life
Chapter 1
Biology: Exploring Life

2. A Big-Billed Bird Rebounds
A Big-Billed Bird Rebounds
Brown pelicans
Are part of the web of life in their environment

3. The brown pelicans’ proximity to humans
Has meant trouble for the species
The brown pelicans’ connection to the environment
Sets the stage for the study of biology

4. THE SCOPE OF BIOLOGY
1.1 Life’s levels of organization define the scope of biology
Life’s structural hierarchy
Defines the scope of biology, the scientific study of life
Biosphere
Ecosystem
Florida coast
Community
All organisms on
the Florida coast
Population
Group of brown
pelicans
Organism
Brown pelican
Spinal cord
Organ system
Nervous system
Brain
Organ
Brain
Nerve
Tissue
Nervous tissue
Figure 1.1
Cell
Nerve cell
Nucleus
Atom
Organelle
Nucleus
Molecule
DNA

5. An ecosystem consists of all the organisms living in a par ticular area
As well as the nonliving environmental components
All the living organisms in an ecosystem
Make up a community

6. A population
Consists of a localized group of individuals of a species
An individual living entity
Is an organism

7. Life is organized in a hierarchical fashion.
Life is organized in a hierarchical fashion.
Molecule
Cell
Tissue
Organ
Organ system
Organism
Population
Community
Ecosystem

8. 1.2 Living organisms and their environments form interconnecting webs
1.2 Living organisms and their environments form interconnecting webs
Ecosystems are characterized by the cycling of chemical nutrients from the atmosphere and soil to producers to consumers to decomposers and back to the environment.
Organisms exchange chemical nutrients that results in a change of energy.
Ex. A consumer eating a producer represents a transfer of chemical nutrients and energy.

9. Energy flows one-way through an ecosystem
Energy flows one-way through an ecosystem
From the sun (the ultimate source of energy in an ecosystem) to producers to consumers and exits as heat
Sun
Air
Inflow of
light
energy
Loss of
heat
energy O2
CO2
CO2
Chemical
energy
Cycling of
Chemical
nutrients
Producers
Consumers
Decomposers
H2O
Figure 1.2
Soil
Ecosystem

10. 1.3 Cells are the structural and functional units of life
1.3 Cells are the structural and functional units of life
A cell is the basic unit of life
Characteristics of cells:
Cells respond to the environment.  
Cells develop and maintain complex organization.  
Cells take in and use energy.  
Cells regulate their internal environment.  

11. New proper ties emerge from the complex organization of a system, such as a cell.
The formation of systems typically results in the appearance of novel characteristics called emergent properties.

12. Lack membrane-enclosed organelles and a nucleus, but do have DNA
Eukaryotic cells
Contain membrane-enclosed organelles, including a DNA-containing nucleus
Prokaryotic cells
Lack membrane-enclosed organelles and a nucleus, but do have DNA
Nucleus
(contains DNA)
Prokar yotic cell
Eukar yotic
cell
DNA
(no nucleus)
Organelles
Figure 1.3
25,000 

13. EVOLUTION, UNITY, AND DIVERSITY
1.4 The unity of life: All forms of life have common features
DNA is the genetic information for constructing the molecules that make up cells and organisms
Differences among organisms reflect different nucleotide sequences in their DNA.

14. Each species’ genetic instructions
Each species’ genetic instructions
Are coded in the sequences of the four building blocks making up DNA’s two helically coiled chains A C T A T A C C G T A G T A
Figure 1.4A

15. All organisms share a common set of features: Complex organization
All organisms share a common set of features:
Complex organization
Regulation of internal conditions (homeostasis)
Figure 1.4B
Figure 1.4C

16. Growth and development The ability to take in energy and use it
Growth and development
The ability to take in energy and use it  
Response to environmental stimuli
The ability to reproduce and evolve
Figure 1.4D
Figure 1.4E

17. 1.5 The diversity of life can be arranged into three domains
1.5 The diversity of life can be arranged into three domains
Organisms are classified into the prokaryotic domains Bacteria and Archaea and the eukaryotic domain Eukarya

18. Domains Bacteria and Archaea
Domains Bacteria and Archaea
All lack a nucleus and membrane bound organelles.
SEM 3,250
Figure 1.5A
SEM 25,000
Figure 1.5B

19. Domain Eukarya includes Protists-unicellular
Domain Eukarya includes
Protists-unicellular
The kingdoms Fungi, Plantae, and Animalia are all multicellular
Fungi-heterotrophic absorb food
Plantae-autotrophic,
cell wall made of
cellulose
Animalia-heterotrophic,
no cell wall made of

20. 1.6 Evolution explains the unity and diversity of life
1.6 Evolution explains the unity and diversity of life
Charles Dar win synthesized the theory of evolution by natural selection.
Evolution is a passive process
Figure 1.6A

21. Darwin’s Mechanism of Natural Selection
Individuals in a population exhibit variations, some of which are heritable.  
Factors in the environment result in some organisms with better reproductive success than others.
Natural selection is based in part on the overproduction of offspring.
Natural selection can lead to the appearance of new species.  

22. Natural selection is an editing mechanism that occurs when populations or organisms, having inherited variations, are exposed to environmental factors that favor the reproductive success of some individuals over others 1
Populations with varied inherited traits 2
Elimination of individuals with certain traits
Figure 1.6B 3
Reproduction of survivors

23. Evolution by natural selection relies upon: Heritable variation.
All organisms have adaptations that have evolved by means of natural selection
Evolution by natural selection relies upon:
Heritable variation.  
Overproduction
of offspring.
Struggle for existence.  
Individual variation.
Figure 1.6C

24. 1.7 Scientists use two main approaches to learn about nature
THE PROCESS OF SCIENCE
1.7 Scientists use two main approaches to learn about nature
Science
Is a way of knowing
Seeks natural causes for natural phenomena

25. Discovery Science In discovery science
Discovery Science
In discovery science
Scientists describe some aspect of the world and use inductive reasoning to draw general conclusions

26. Inductive reasoning is making a conclusion based on a set of data.
Deductive reasoning starts with a general rule, then from that rule, we make a conclusion about something specific.
Example: If all vertebrates have backbones, and turtles are vertebrates, then turtles have backbones.
Inductive reasoning is making a conclusion based on a set of data.
Example: All sheep that I've seen are white. All sheep must be white

27. Hypothesis-Based Science
Hypothesis-Based Science
In hypothesis-based science
Scientists attempt to explain obser vations by testing hypotheses (a tentative answer to some question)

28. 1.8 With hypothesis-based science, we pose and test hypotheses
1.8 With hypothesis-based science, we pose and test hypotheses
To be scientifically valid, a hypothesis must be testable and falsifiable.
Hypothesis-based science involves:
Obser vations, questions, hypotheses as tentative answers to questions
Deductions leading to predictions, and then tests of predictions to see if a hypothesis is falsifiable

29. A Case Study from Ever yday Life
A Case Study from Ever yday Life
Deductive reasoning is used in testing hypotheses as follows
If a hypothesis is correct, and we test it, then we can expect a par ticular outcome
Observations
Question
Hypothesis # 1:
Dead batteries
Hypothesis # 2:
Burnt-out bulb
Prediction:
Replacing batteries
will fix problem
Prediction:
Replacing bulb
will fix problem
Test prediction
Test prediction
Figure 1.8A
Test falsifies hypothesis
Test does not falsify hypothesis

30. Percent of total attacks
A Case Study of Hypothesis-Based Science
In experiments designed to test hypotheses
The use of control groups and experimental groups helps to control variables
The role of a control in an experiment is to provide a basis of comparison to the experimental group.
100
Artificial king snakes
83%
84% 80
Artificial brown snakes 60
Percent of total attacks
on artificial snakes
Figure 1.8B
Figure 1.8C 40 20
17%
16%
Coral snakes
absent
Coral snakes
present
Figure 1.8E
Figure 1.8D

31. BIOLOGY AND EVERYDAY LIFE CONNECTION
1.9 Biology is connected to our lives in many ways

32. Biology is connected to many impor tant issues in our lives
Biology is connected to many impor tant issues in our lives
Environmental problems and solutions
Genetic engineering
Medicine
Figure 1.9

33. Many technological advances stem from scientific research
The science-technology-society relationship is an impor tant aspect of a biology course
Science-goal is to understand natural phenomena; “discoveries”
Technology-goal is to apply scientific knowledge for some specific purpose; “inventions”