Chapter 1
The Science of Life
Chapter 1:
Biology: the study of life

What is Life?
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
1.1 Characteristics of life

All living things have common characteristics
 Organization – and made up of cells
 Response to Stimuli
 Homeostasis
 Metabolism
 Growth and Development
 Reproduction
 Evolution-Change through Time
Section 1.1Levels of Organization
BIOSPHERE
 ECOSYSTEM
 COMMUNITY
POPULATION
 ORGANISM


ORGAN SYSTEM
ORGANS


TISSUES

CELL

ORGANELLE
MOLECULE


ATOM
LEVELS OF ORGANIZATION
Section 1.1 – Organization- 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 

1.1 Characteristics of life

Distinguish between:

Metabolism versus homeostasis?

Growth and Development versus
Evolution?
1.2 Themes in Biology

Diversity & Unity (all living things have certain
traits in common)
Three Domains – Archaea, Eubacteria, Eukaryota

Interdependence of Organisms

Evolution of Life
Natural Selection & Adaptation
1.2 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
1.2 Evolution –Natural Selection

Charles
Darwin
Artificial
selection
Vs
Natural
Selection
1.2 Evolution – Natural Selection
1
2
Populations with varied inherited traits
Elimination of individuals with certain traits
1.2 Diversity & Unity --The Galapagos Islds

Finches

Beak size

Teddy Graham Lab –We’ll do this later
on!!
Section 1.2 Interdependence of organisms

Food Web




Producers
Consumers
Decomposer
Dynamic of an Ecosystem


Energy Flow
Recycling
chemical
nutrients
1.2 Interdependence of Organisms
1.3 Scientific Method
1)
2)
3)
4)
5)
6)
7)
Observation
Hypothesis
Prediction
Experiment
Results (Data tables)
Conclusion/ Evaluation
Communication to scientific peers
1.3 Scientific Method
1)
2)
3)
4)
5)
6)
7)
Observation
Hypothesis
Prediction
Experiment
Results (Data tables)
Conclusion/ Evaluation
Communication to scientific peers
1.3 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
 Record results—DATA TABLES!!
 Repeat the tests for consistency
 Draw conclusions & suggestions for improvement
 Communicate results
1.3 Law versus Theory
Compare:
Hypothesis vs. Theory vs. Law??
1.3 Law versus Theory
Hypothesis- an educated guess

Even if supported by a couple of
experiments, it is not widely
supported as a general rule
1.3 Law versus Theory
Theory Highly tested

Generally accepted principle -explains a vast number of
observations and experimental data
1.3 Law versus Theory
Theory A theory explains how nature works.
 Widely accepted
 Explains vast amount of data
 Synthesis –E.g., Theory of Evolution
 Often non-mathematical (but may be
math within studies supporting theory).
1.3 Law versus Theory
Law- describes what nature does under
certain conditions
 Predicts what will happen as long as
those conditions are met.
 Often times mathematically defined
(once again, a description of how nature
behaves)
1.4 Microscope
1.4 Microscope
Ocular x Objective lens = Total Magnification
1.4 Microscope
Magnification Vs Resolution
1.4 Microscope
Magnification Vs Resolution
Repetition - Trials
1. What is the purpose of repetition in science?
a)
b)
To over come human error or randomness
Eg. Large sample populations, same experiment
many times over with the same results.
2. Will repetition eliminate systematic errors?
a)
NO! A scientist has to allow for margin of error or
adjust, like aiming higher to compensate or
mechanically adjust the scope.
Metric Prefixes
Converting one metric unit to
another
k

h
da
Basic unit
(m, L, g)
d
c
m
To convert from one unit to another, move the
decimal same direction and number of
places the units are from each other

12 kilometers is ?? centimeters



centimeters are 5 places to the right
1,200,000 cm
134 decigrams is ?? hectograms


hectograms are 3 places to the left
0.134 hg
Accuracy vs. Precision
Scientific Method –
Precision versus
Accuracy
Accuracy describes the nearness of
a measurement to the standard or
true value
NOT
accurate
– not
close to
expected
target
4. Target Analogy to Sci. Method
1.
2.
3.
4.
Target is the expected outcome
The holes represent actual outcome
Precision and accuracy represent
analysis of results
In science we analyze expected vs.
actual outcomes and come to
conclusions
Accuracy vs. Precision
Scientific Method –
Precision versus
Accuracy
Precision is the degree to which
several measurements provide
answers very close to each other. It
is an indicator of the scatter in the
data and validity of your methods.
NOT
precise –
points
not close
togethernot done
in same
way

NOT
Accurate
– not
close to
target

NOT
precise —
not close
to each
other


NOT
Accurate –
not close
to target
PRECISE
—close to
each other
--little spead
of data

ACCURATE –
not close to
target

PRECISE —
close to each
other – little
spread


ACCURATE – Depends on YOU!
PRECISION– depends on the
equipment—the increments to which it is
marked
 -the more decimal places marked to the
better
Can you hit the bull's-eye?
Three targets
with three
arrows each to
shoot.
How do they
compare?
Both
accurate
and precise
Precise
but not
accurate
Neither
accurate nor
precise
Can you define accuracy and precision?
Scientific Method - Graphing

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
Positive Relationshipverse
Relationship y= a/x
Direct Relationship
Inverse or Negative
Relationship y= a/x
No relationship
Quadratic relationship y=ax2 + bx +c
parabola
Chapter 3
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.
Ch 3-
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
Ch 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
Ch 3 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

Ch 3 - 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)
Ch 3 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-
Valence Shell Electrons
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
CHAPTER 3.1 - Carbon Compounds
some organic molecules
Methane
Go to
Section:
Acetylene
Butadiene
Benzene
Isooctane
CHAPTER 3.1 - Carbon Compounds
Carbohydrates
Forms
SUCROSE
from
dehydration
synthesis
Go to
Section:
CHAPTER 3.1 - Carbon Compounds
Carbohydrates
Go to
Section:
CHAPTER 3.2 Proteins
AMINO ACID MONOMER
Go to
Section:
CHAPTER 3.2 Proteins
AMINO ACID POLYMER = PROTEIN
Go to
Section:
CHAPTER 3.2 - Carbon Compounds
FATTY ACIDS
Go to
Section:
CHAPTER 3.2 - Carbon Compounds
NUCLEIC ACIDS
Go to
Section:
CHAPTER 3.2 - Carbon Compounds
NUCLEIC ACIDS
Go to
Section:
CHAPTER 3.2 - Carbon Compounds
BICARBONATE—
Buffer in Blood
HC3O-
Go to
Section:
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
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
Ice is less dense than liquid
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
