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

2. A Big-Billed Bird Rebounds
Some core themes underlie all of biology: evolution, cells as the fundamental unit of life, a nearly universal genetic code, the relation of structure and function
The brown pelican is an example of the connection between organisms and their environment

4. 1.1 Life’s levels of organization define the scope of biology
These levels represent a hierarchy
Starting with the biosphere, each level is less inclusive than the one below it

5. Biosphere: all the environments of Earth that support life
Ecosystem: All the living and nonliving components of a particular environment
Community: All the living organisms in an ecosystem
Population: an interacting group of individuals of one species
Organism: An individual living entity

6. The hierarchy continues downward with
Organ systems
Organs
Tissues
Cells
Organelles
Molecules
Atoms

7. Biosphere
Ecosystem
Florida coast
Community
All organisms on
the Florida coast
Population
Group of brown
pelicans
Organism
Brown pelican
Organ system
Nervous system
Organ
Brain
Spinal cord
Nerve
Tissue
Nervous tissue
Nucleus
Cell
Nerve cell
Organelle
Molecule
DNA
Atom

8. 1.2 Living organisms and their environments form interconnecting webs
Producers-photosynthetic organisms-use energy from the sun to produce food
Consumers are ultimately dependent on producers for food
Decomposers break down dead organic material, which is recycled

9. The dynamics of an ecosystem include two major processes:
The cycling of chemical nutrients
The one-way flow of energy, entering as sunlight and leaving as heat

10. LE 1-2 Inflow of light Loss energy of heat energy Chemical energy
Sun
Air
Inflow of
light
energy
Loss of
heat
energy O2
CO2
CO2
Chemical
energy
Cycling of
chemical
nutrients
Consumers
Producers
Decomposers
H2O
Soil
Ecosystem

11. 1.3 Cells are the structural and functional units of life
Cells perform all functions necessary for life
Regulate their internal environment
Take in and use energy
Respond to the local environment
Develop and maintain their complex organization
Divide to form new cells

12. Theme of emergent property
"The whole is greater than the sum of its parts"
The combination of the parts that form a more complex organization is called a system

13. Two basic types of cells: prokaryotes and eukaryotes
Prokaryotes are smaller and less complex than eukaryotes and lack a nucleus and other organelles
Eukaryotes are generally larger and more complex and contain a nucleus and other organelles

14. LE 1-3
Nucleus
(contains
DNA)
Eukaryotic cell
Prokaryotic cell
DNA
(no nucleus)
Organelles
25,000 

15. EVOLUTION, UNITY, AND DIVERSITY
1.4 The unity of life: All forms of life have common features
Genetic information within all cells is coded in DNA molecules
Each DNA molecule is made up of chains of four chemical "building blocks"

16. Other common properties of organisms:
Order
Regulation
Growth and development
Energy use
Response to the environment
Reproduction
Evolution

21. 1.5 The diversity of life can be arranged into three domains
Scientists have identified about 1.8 million species-particular types of organisms
Taxonomy classifies species into a hierarchy of increasingly broad groups

22. Three domains are the most overarching groups:
Domain Bacteria, unicellular prokaryotes (cells that lack a nucleus)
Domain Archaea, unicellular prokaryotes
Domain Eukarya, unicellular and multicellular eukaryotes (cells with a nucleus), including protists, plants, animals, and fungi

25. LE 1-5c Kingdom Fungi Kingdom Animalia Protists (multiple kingdoms)
275
Kingdom Animalia
Protists (multiple kingdoms)
Kingdom
Plantae

26. 1.6 Evolution explains the unity and diversity of life
Charles Darwin proposed the theory of evolution by natural selection
Species evolved from ancestors through "descent with modification"
Natural selection occurs as heritable variations are exposed to environmental factors that favor the reproductive success of some individuals over others
The product of natural selection is adaptation

27. Population with varied inherited traits
LE 1-6b
Population with varied inherited traits
Elimination of individuals with certain traits
Reproduction of survivors

28. 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
Discovery science
Primarily describes nature through verifiable observations and measurements
Hypothesis-driven science
Attempts to explain nature by studying questions drawn from observations made during "discovery science"
Hypothesis: a tentative answer to a problem or question that is being asked

29. 1.8 With hypothesis-based science, we pose and test hypotheses
Hypothesis-based science applies the five steps of the scientific method:
(1) Observations from others or results of earlier tests
(2) Questions about unclear aspects of the observations: How? Why? When?

30. (3) Hypotheses or tentative explanations of a phenomenon
Must be testable
Must be falsifiable
(4) Predictions developed by the use of deductive reasoning (if...then)
(5) Tests of predictions to determine if the predictions are supported or falsified.

31. A Case Study from Everyday Life
Following the scientific method to discover why a flashlight doesn't work
Using deductive reasoning to test alternative hypotheses
If a hypothesis is correct, and we test it, then we can expect a particular outcome

32. Observations Question
LE 1-8a-1
Observations
Question
Hypothesis #1:
Dead batteries
Hypothesis #2:
Burnt-out bulb

33. LE 1-8a-2
Observations
Question
Hypothesis #1:
Dead batteries
Hypothesis #2:
Burnt-out bulb
Prediction:
Replacing batteries
will fix problem
Prediction:
Replacing bulb
will fix problem

34. Test falsifies hypothesis Test does not falsify hypothesis
LE 1-8a-3
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
Test falsifies hypothesis
Test does not falsify hypothesis

35. A Case Study of Hypothesis-Based Science
Following the scientific method to test an hypothesis about the function of biological mimicry
Predict that mimicry should protect coral snakes in the areas where king snakes live
Develop a controlled experiment using artificial snakes
Summarize results confirming prediction in a graph

39. Percent of total attacks
LE 1-8e
100
Artificial king snakes
83%
84% 80
Artificial brown snakes 60
Percent of total attacks
on artificial snakes 40 20
17%
16%
Coral snakes
absent
Coral snakes
present

40. BIOLOGY AND EVERYDAY LIFE CONNECTION
1.9 Biology is connected to our lives in many ways
Technology applies scientific knowledge for a specific purpose
Biology and technology affect our everyday lives
Environmental problems and solutions
Genetic engineering
Medicine