Chapter 1
Biology Exploring Life
Chapter 1:
Biology: the study of life

What is Life?
Section 1.1Levels of Organization
BIOSPHERE
 ECOSYSTEM
 COMMUNITY
POPULATION
 ORGANISM


ORGAN SYSTEM
ORGANS


TISSUES

CELL

ORGANELLE
MOLECULE


ATOM
Cover the broad scope of biology
Section 1.2 Living organisms and their environment for
interconnecting webs

Food Web




Producers
Consumers
Decomposer
Dynamic of an Ecosystem


Energy Flow
Recycling
chemical
nutrients
Section 1.3 Cells are the structural and
functional units of life
Perform all activities required for life

Prokaryotic cell


Simpler, small
Eukaryotic cell

More complex larger
Nucleus
(contains DNA)
Prokaryotic cell
Eukaryotic
cell
DNA
(no nucleus)
Organelles
25,000 

1.4 The unity of life: All living things have
common characteristics

All living things have common characteristics



DNA
Order
Regulation



Growth and Development
Energy utilization




homeostasis
metabolism
Response to environment
Reproduction
Evolution

mutation
1.5 Diversity of Life

Extent of diversity has led to classification
schemes
 K-P-C-O-F-G-S
 Six Kingdoms






Eubacteria
Archeabacteria
Protista-one-celled organisms
Fungi-mold and mushrooms
Plantae- multicellular plants
Animalia; multicellular animals
1.6 Evolution explains the unity
and diversity of life

Charles
Darwin

Artificial
selection
Natural Selection

Observation # 1


Observation # 2


Individual variation
Overproduction and Competition
INFERENCE


Unequal reproductive success
Those with heritable traits best fit the environment
will survive and reproduce
Accumulation of favorable variation in a
population over time
The Galapagos Islands

Finches

Beak size
1
2
3
Populations with varied inherited traits
Elimination of individuals with certain traits
Reproduction of survivors

Teddy Graham Lab
1.7 The Nature of Science
Science is way of knowing
 Seeks causes for natural phenomena


Discovery Science


Inductive reasoning
Hypothesis Based Science

Deductive reasoning
1.8 The Scientific Method

Make an observation
 Ask a Question
 Make a Hypothesis using all known information
 Predict what the outcome would be if the hypothesis is
valid
 Test the hypothesis by experiments, models, and
observations
 Repeat the tests for consistency
 Examine alternative hypotheses in the same manner
 Report objectively on the tests and conclusions
Scientific Method

Independent Variable


Dependent Variable


The variable you have control over
Changes in response to the independent
variable
Controlled Variables

Remain constant so results of the
experiment are valid
What is a scientific theory?

A theory is a related set of hypothesis that for
a broad-ranging explanation of many
phenomena
 Theories are rejected and accepted on the
basis of tests and are subject to revision
 Scientists must be content with relative
certainty the theory is valid
 Theories can change if new scientific evidence
is provided
Does Science have Limits?
It is limited to questions that can be
tested
 Subjective questions cannot be
addressed
 Science may be controversial when it
offers an explanation for something
previously thought the be supernatural

Chapter 2
The Chemical Basis of Life
Nature’s

Chemical Language
The rattlebox moth

Produces chemicals important for mating and
defense
The human body, as all of nature, is made of
chemical elements.
2.1-2.2
element: cannot be broken down to other
substances by ordinary chemical means
 Most common in human body (96%)

Oxygen (O)
 Carbon (C)
 Hydrogen (H)
 Nitrogen (N)


Trace element: small amount is essential
2.3 Elements can combine to form
compounds

Compound: a substance containing two
or more elements in a fixed ratio

More common than pure elements

ex. Vitamin A, Proteins
Sodium
Chlorine
Sodium Chloride
Trace
elements are common additives to
food and water

Dietary deficiencies in trace elements

Can cause various physiological conditions
Figure 2.2A
2.4 Atoms consist of protons, neutrons,
and electrons

Atom: the smallest unit of matter that
still retains the properties of an element
Three subatomic particles

Protons (p+)



Neutrons


atomic nucleus
single positive charge
part of the atomic nucleus they have no charge
Electrons (e-)


have a negative charge; they circle around the nucleus
# of e = # of p
Atomic Number
Defines the element
 equal to the number of of protons
 Is equal to the number of electrons in a
neutral atom
 Always the whole number


Mass number: equal to the number of
protons plus the number of neutrons in
its nucleus
Atomic Mass
Is equal to the number of protons and
neutrons in the nucleus of the atom
(mass number)
 May not be a whole number on the
periodic table
 In biology you may round the atomic
mass to a whole number

2.5 Radioactive isotopes can help or
harm us

Isotopes: different forms of atoms
 Atoms with the same number of protons
and electrons but a different number of
neutrons
 Radioactive isotopes

Nucleus decays spontaneously giving off
particles of energy

Research/Medicine


Radioactive tracers
Dangers

Damage molecules (DNA)
2.6 Electron arrangement determines the
chemical properties of an atom

electron shells: certain energy levels where
electrons occur

Each shell holds up to a certain # of e-
the # of e- in the outermost energy level
determines the chemical properties of an atom
(how it will bond w/other atoms)
Chemical bond: attractions holding atoms
together
Ion – charged atom
Figure 2-3 Ionic Bonding
Ionic bonding
Section 2-1
Sodium atom (Na)
Chlorine atom (Cl)
Sodium ion (Na+)
Chloride ion (Cl-)
Transfer
of electron
Protons +11
Electrons -11
Charge
0
Protons +17
Electrons -17
Charge
0
Protons +11
Electrons -10
Charge
+1
Protons +17
Electrons -18
Charge
-1
Transfer of Electrons from one atom to another
Figure 2-3 Ionic Bonding
Section 2-1
Sodium atom (Na)
Chlorine atom (Cl)
Sodium ion (Na+)
Chloride ion (Cl-)
Transfer
of electron
Protons +11
Electrons -11
Charge
0
Protons +17
Electrons -17
Charge
0
Protons +11
Electrons -10
Charge
+1
Protons +17
Electrons -18
Charge
-1
Transfer of electrons
Covalent Bond
Sharing of electrons
 Electrons are not completely transferred
to another atom

Rules for drawing covalent bonded
molecules






2 electrons 1 bond 1 line
You can form more than one bond between
atoms
Carbon 4 bonds
Oxygen always has 2 bonds and 2 lone pairs
Hydrogen always has 1 bond
Nitrogen has 4 bonds or 3 bonds and a lone
pair of electron
Figure 2-11 Carbon Compounds
some organic molecules
Section 2-3
Methane
Go to
Section:
Acetylene
Butadiene
Benzene
Isooctane
2.9 Unequal electron sharing
creates polar molecules

Atoms in a covalent bond are in a constant
tug-of-war for the shared electrons

Electronegativity: an atom’s attraction for its
electrons, including shared electrons

Nonpolar: atoms exert an equal pull on the
electrons

Polar: unequal sharing of electrons
Water
polar molecule
Hydrogen Bonding

In a hydrogen bond, an atom or molecule
interacts weakly with a hydrogen atom
already taking part in a polar covalent
bond
Hydrogen Bonds
Hydrogen bonds form any time a
hydrogen atom is bonded to an F, O, N
 They are weak bonds between to
molecules
 Hydrogen bonds make liquid water
cohesive

Properties of water





Water is polar
Hydrophilic; water
loving
Hydrophobic; water
hating
Cohesive properties
due to hydrogen
bonding
Universal solvent
2.12 Water’s hydrogen bonds moderate
temp.

Heat


Warming



The amount of energy associated with the movement of
atoms and molecules in the body
Disrupts (H) bonds then speeds up molecules
Store large amounts of heat while warming a few degrees
Cooling

Heat energy is released when (H) bonds form, slowing
the cooling process
2.13 Ice is less dense than liquid
2.14 Water is the solvent of life
Solution: liquid consisting of a uniform
mixture of two or more substances
 Solvent: dissolving agent
 Solute: substance that is dissolved

Figure 2-9 NaCI Solution
Water as a Solvent
Section 2-2
ClCl-
Na+
Na+
Water
Go to
Section:
Water
NaCl as the solute
Acids, Bases and Salts
Acid is a proton donor (H+), have a pH
less than 7
 Base is an proton acceptor; has a pH
greater than 7
 A salt is formed when and acid reacts
with a base
 Buffer is a solution that is resistance to
pH change

The pH scale
pH is a measure of the H+ concentration
in a solution
 The greater the H+ the lower the pH
