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

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

1.1 Characteristics of life

Section 1.1Levels of Organization

BIOSPHEREECOSYSTEM

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)

Eukaryotic

cell

Prokaryotic cell

DNA

(no nucleus)

Organelles

25,0

00

Distinguish between:

Metabolism versus homeostasis?

Growth and Development versus Evolution?

1.1 Characteristics of life

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 Themes in Biology

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

3

Populations with varied inherited traits

Elimination of individuals with certain traits

Reproduction of survivors

1.2 Evolution – Natural Selection

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) Observation

2) Hypothesis

3) Prediction

4) Experiment

5) Results (Data tables)

6) Conclusion/ Evaluation

7) Communication to scientific peers

1.3 Scientific Method

1) Observation

2) Hypothesis

3) Prediction

4) Experiment

5) Results (Data tables)

6) Conclusion/ Evaluation

7) Communication to scientific peers

1.3 Scientific Method

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

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)

1.3 Law versus Theory

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) To over come human error or randomness

b) 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 d c m

(m, L, g)

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. Target is the expected outcome

2. The holes represent actual outcome

3. Precision and accuracy represent

analysis of results

4. 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

together-

not 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

Three targets with three arrows each to shoot.

Can you hit the bull's-eye?

Both accurate and precise

Precise but not accurate

Neither accurate nor precise

How do they compare?

Can you define accuracy and precision?

Scientific Method - Graphing

Independent Variable

The variable you have control over

Dependent Variable

Changes in response to the independent

variable

Controlled Variables

Remain constant so results of the

experiment are valid

Direct Relationship

Positive Relationshipverse

Relationship y= a/x

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

Ch 3- The human body, as all of nature, is made of

chemical elements.

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+) atomic nucleus

single positive charge

Neutrons 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

Sodium atom (Na) Chlorine atom (Cl) Sodium ion (Na+) Chloride ion (Cl-)

Transferof 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

Section 2-1

Figure 2-3 Ionic Bonding

Ionic bonding

Transfer of Electrons from one atom to another

Sodium atom (Na) Chlorine atom (Cl) Sodium ion (Na+) Chloride ion (Cl-)

Transferof 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

Section 2-1

Figure 2-3 Ionic Bonding

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

some organic molecules

Methane Acetylene Butadiene Benzene Isooctane

CHAPTER 3.1 - Carbon Compounds

Go to

Section:

CHAPTER 3.1 - Carbon Compounds

Carbohydrates

Go to

Section:

Forms

SUCROSE

from

dehydration

synthesis

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

Go to

Section:

BICARBONATE—

Buffer in Blood

HC3O-

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

The amount of energy associated with the movement of

atoms and molecules in the body

Warming

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

Water as a Solvent

Cl-

Water

Cl-

Na+

Water

Na+

Section 2-2

Figure 2-9 NaCI Solution

Go to

Section:

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