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

2. A Big-Billed Bird Rebounds!
Main Idea:
Brown pelicans are magnificent birds who’s interaction with humans almost lead to their extinction.
Who? What? When? Where? Why? How?

3. 1.1 Life’s levels of organization define the scope of biology.

4. Levels of Organization (Largest Smallest)
Biosphere Ecosystem Community Population Organism Organ Systems
Organs Tissues Cells
Cell Organelles Molecules/Compounds Atoms

5. Levels of Organization (from most inclusive to least inclusive)
Biosphere: All the environments on Earth that support life.
Ecosystem: consists of all the organisms living in a particular area, as well as all the nonliving, physical components of the environment with which organisms interact, such as air soil, water, and sunlight.
Community: the combination of all the different species (all living things) in an ecosystem.

6. Levels of Organization (cont’d)
Population: an interacting group of individuals of one species. (Example: brown pelicans)
Organism: an individual living thing.
Organ System: several organs that work together. (Example: circulatory system, digestive)
Organs: a group of tissues that work together. (Example: heart, kidney, ect.)

7. Levels of Organization (cont’d)
Tissues: a group of similar cells that work to accomplish a specific function. (Example: heart tissue, muscle tissue, skin tissue, etc.)
Cell: a unit of living matter separated from it’s environment by a boundary called a membrane.
Organelle: structure that performs a specific task inside the cell.
Molecule: a cluster of atoms held together by chemical bonds.
Atom: the smallest particle of ordinary matter.

8. 1.2 Living Organisms and their environments form interconnecting webs.
Living and nonliving organisms in an ecosystem make up a complex web of relationships.
Producers: plants and other photosynthetic organisms that create their own food. Photosynthesis occurs (chapter 6)
Consumers: organisms that eat producers and other consumers. Cellular respiration occurs (chapter 6)
Decomposers: transform dead matter into simple mineral nutrients that plants can use.

9. 1.2 Living Organisms and their environments form interconnecting webs.
Ecosystems include 2 major processes:
1) Recycling of chemical nutrients
Decomposers break down nutrients in dead/decaying organisms and release them for reuse
2) Flow of energy through an ecosystem
Sun → plants (producers) → consumers → heat energy

10. 1.3 Cells are the structural and functional units of life.
The cell is the lowest level of structure that can perform all activities required for life.
Prokaryotic Cells: no membrane-bound organelles (nucleus), smaller and simpler; EX: bacteria
Eukaryotic Cells: Larger, more complex, organelles; EX: all other cells (including us!!)

11. 1.4 All forms of life have common features
Order: Complex organization; made up of cells
Regulation: maintain internal environment (homeostasis)
Growth and development
Use of Energy: take in energy and use it to perform life’s functions
Response to the environment (stimuli)
Reproduction
Evolution: species change over time

12. 1.5 The diversity of life can be grouped into 3 domains
Bacteria = Eubacteria kingdom (common bacteria)
Archaea = Archaebacteria kingdom (bacteria living in extreme environments)
Eukarya = Protist, Fungi, Plant, and Animal kingdoms

13. 1.7 Scientists use 2 main approaches to learn nature
1) Discovery Science - describing nature
Inductive reasoning: Develop general principles from a large number of observations
2) Hypothesis-Based Science - Proposing and testing hypotheses
Hypothesis: a possible explanation; a proposed answer; an educated guess; Must be testable
Deductive reasoning: “If-then” reasoning
Proper hypothesis:
If a Biology student doesn’t study for a test, then that student will fail. – NO I, me, my, we, our

14. Develop questions (identify a problem)
Hypothesis-based science is not a rigid set of steps, but a systematic way of solving scientific problems or understanding an observation (Scientific Method)
Make observations
Develop questions (identify a problem)
Form a hypothesis to explain observations = Educated guess- statement, not question!
Make predictions
Test the hypothesis/predictions with an experiment
Do the experiment, collect data and analyze the data and draw conclusions
Does the data support your hypothesis?
If not, check your experiment or reject hypothesis – you may need a new hypothesis

15. Controlled experiments
Variable: a factor that can change
Independent variable (manipulated variable): causes change in another variable (dependent variable
Dependent variable (responding variable): changes in response to the independent variable
Constant: a condition that does not change.
Control group: a test system where all variables are identical to the experiment except the independent variable.
Experimental group: contains the independent variable

16. Theory vs. Law
Theory - A well tested explanation for a wide range of observations
Supported by a large body of evidence
Future evidence can cause a theory to change or be rejected
Scientific Law – Rule of nature; describes an observed pattern in nature without attempting to explain it

17. 1.9 Biology is connected to our lives in many ways
Global warming, genetically engineered crops, endangered species, etc…
Science Technology Society relationship is an important one