Biology Notes
Chapter 1

Characteristics of Life (Pg. 2)
- Response to the environment
- Reproduction
- Growth and Development
- Regulation (homeostasis)
- Energy processing
- Evolutionary adaptation
- Order (the highly ordered structure that characterizes life)

Levels of Biological Organization (Pg. 4)
- Molecule< organelles< cells< tissues< organs and organ systems< organisms< populations<
communities< ecosystems< biosphere

Emergent Properties (Pg. 3)
- Definition: new or interesting properties that emerge at each step up in the biological hierarchy,
the properties are not present at the preceding level
- Due to the arrangement and interactions of parts as complexity increases
o Ex. A serious head injury can disrupt the architecture of a human brain and the mind
may not function properly, even if all the brain parts are still present
o Ex. Large groups of insects have complex social systems
- Characterize non-biological entities

Reductionism
- Definition: reduction of complex systems to simpler components that are easier to study
o Ex. Thousands of neurons combine to form the nervous system

Systems Biology (Pg. 6)
- Systems: they are simply a combination of components that function together
- Balances reductionism with the study of emergent properties
o Ex. Similar to moving from ground level on a street corner to a helicopter high above the
city, where you can see various crashes, construction, traffic lights and how they affect
the traffic in the city
- Goal of systems biology is to construct models for the dynamic behavior of whole biological
systems. Successful models help biologists predict how a change in one or more variables will
affect other components and the whole system.

Organisms interact with their environments, exchanging matter and energy
- Each organism interacts continuously with its environment, which includes both nonliving
factors and other organisms
- 2 major processes:
o The cycling of chemical nutrients (Ex. Minerals absorbed by a tree are eventually
returned to the soil)
o Energy flow (Ex. Energy pyramid or food web, transfer of energy through ecosystem)
o Light is the fundamental energy that drives the whole system

Energy conversion
- Work requires energy
- Energy is stored in light, thermal, chemical, kinetic, or thermal forms
- Energy exchange between organisms and the environment involves energy transformations
- Chemical nutrients recycle within an ecosystem; Energy flows through an ecosystem, usually
entering as sunlight and exiting as heat

Cells are an organism’s basic unit of structure and function (Pg. 7-8)
- A cell is the lowest unit of organization that is a living organism
- All cells are enclosed by a phospholipid membrane and use DNA as genetic info
- 2 main forms of cells:
o Eukaryotic Cell: subdivided into various membrane-enclosed organelles, the nucleus
contains DNA, organelles are located in the cytoplasm
o Prokaryotic Cell: No nucleus and DNA is not separated from the rest of the cell, no
organelles

Continuity of life is based on heritable info called DNA (Pg. 8-11)
- Chromosomes contain almost all of the cell’s DNA
- DNA is made up of genes: the units of inheritance that transmit info from parents to offspring
- Genome: the entire collection of genetic instructions that an organism inherits
- Bioinformatics: the use of computational tools to store, organize, and analyze the huge volume of
data that result from high-throughput methods

Feedback mechanisms regulate biological systems
- In feedback regulation, the product (output) of a process self-regulates
- Negative Feedback: more product accumulating  process slowing down and less product being
produced
- Positive Feedback: (favorable but less common) more product accumulating  process speeding
up and more product being produced
o Ex. In labor, a chemical is released more and more  contractions get closer and closer

Evolution accounts for the unity and diversity of life (Pg. 12)
- Taxonomy: the branch of bio that names and classifies animals
- Naming is like, Genus species, or it’s underlined when writing; the species is never capitalized,
Latin names are used
o Ex. Ursus americanus (American black bear)
- Organizing the diversity of life:
o Domain> Kingdom> Phylum> Class> Order> Family> Genus> Species
- 3 domains of life:
o Domain Bacteria: most diverse and widespread prokaryotes
o Domain Archaea: prokaryotes that live in extreme environments (also called
extremophiles; expected to be found on Mars)
o Domain Eukarya:
 Includes 3 multicellular Kingdoms:
 Kingdom Plantae: produce their own sugars and food by
photosynthesis

-
Kingdom Fungi: absorb dissolved nutrients from their surroundings,
many decompose dead organisms and wastes
 Kingdom Animalia: obtain food by ingestion of other organisms
 Kingdom Protista: single-celled eukaryotes (also includes some multicellular
forms, seaweed, that are closely related to unicellular protists)
Striking unity underlies the diversity of life, evident in many features of cell structure
o Ex. Cilia of Paramecium is similar to cilia of Windpipe cells

Evolution and Natural Selection (Pg. 14-18)
- Fossils and other evidence document evolution of life
- Charles Darwin published On the Origin of Species by Means of Natural Selection
o 2 main points:
 Presented evidence to support his view that contemporary species arose from a
succession of ancestors; called this evolutionary history of species “descent with
modification”
 Proposed a mechanism for descent with modification; it’s called theory of
natural selection
 Darwin observed that individuals in populations have varied traits,
traits are heritable, more offspring is produced than what can survivecompetition is inevitable, and species suit their environments
 Reasoned that individuals best suited to their environments are more
likely to survive and reproduce
o Darwin proposed natural selection could cause ancestral species to give rise to 2 or
more descendant species
 Ex. Finches in Galapagos Islands
o Natural selection is evident in adaptations of organisms to environment
 Ex. Bat wings
- Evolution occurs as the unequal reproductive success of individuals adapts the population to its
environment

Scientists use inquiries (Pg. 18)
- Definition: a search for info and explanation, often focusing on specific questions
- 2 main types:
o Hypothesis-based Science: about explaining nature and what causes something to
happen, involves proposing and testing hypotheses
o Discovery Science: describes natural structures and processes through careful
observation and analysis of data
- Data
o Quantitative: recorded measurements
o Qualitative: descriptions
- Inductive reasoning: derivation of generalizations from a large number of specific observations;
specific  general
o Ex. The sun always rises in the east
- Deductive reasoning: extrapolating the specific results we should expect from general premises
that are true; general  specific
o Ex. If all organisms are made of cells, and humans are organisms, then humans are
composed of cells

Hypothesis (Pg. 19)
- Definition: a tentative answer to a well-framed questions, an explanation on trial
- Leads to predictions that can either be tested for validity or falsified
- Observations and results must be repeatable
- Science can’t support or falsify supernatural explanations (it’s outside of bounds, can’t be tested)

Theory (Pg. 23)
- Definition: a theory is broader than a hypothesis, general and can lead to a new hypothesis, and
is supported by a large body of evidence
- Models are used to represent natural phenomena and are predictive tools

Controlled Experiment (Pg. 22)
- Definition: one that is used to compare an experiment group with a control group
- Experimental group and control group ideally only vary in the factor that is being tested
- Researchers “control” unwanted variables not by eliminating them through environmental
regulation, but by canceling their effects by using control groups

Technology (Pg. 24)
- Definition: technology applies scientific knowledge for some specific purpose
- The goal of science is to understand natural phenomena; biologists often speak of “discoveries”
while engineers speak of “inventions”