BIO REVIEWER 2.

Phosphate group (negative charges

Humans share 50% of their DNA with 3. Nitrogen Base (purine or

bananas. pyrimidine)

Cells can contain 6- 9 feet of DNA. If

all the DNA in your body was put end
to end, it would reach to the sun and
back over 600 times.

DNA in all humans is 99.9 percent

identical. It is about one tenth of one
percent that makes us all unique, or
DNA RNA
about 3 million nucleotides Structure Double Single
difference. stranded
Sugar Deoxyribos Ribose
DNA can store 25 gigabytes of
e
information per inch and is the most
Nitrogen A-T/G-C A-U/G-C
efficient storage system known to base-pair
human. Types 1 3
Location Nucleus Inside or
In an average meal, you eat
outside of
approximately 55,000,000 cells or nucleus
between 63,000 to 93,000 miles of
DNA.
DNA: repository of genetic
It would take a person typing 60 information; encodes the blueprint
words per minute, eight hours a day, for life processes
around 50 years to type the human
genome. - composed of two
complimentary strands of
DNA is composed of units called nucleotides joined by
NUCLEOTIDES , which are composed hydrogen bonds
of three sub molecules:
Adenine with Thymine (A T or T A)
1. Pentose Sugar deoxyribose
They join with 2 hydrogen bonds
Cytosine with Guanine (C G or G C)

They join with 3 hydrogen bonds

DNA and RNA are polynucleotides

- They are made up of smaller

molecules called nucleotides.
- DNA is made of two
polynucleotide strands:
RNA: information in the form of base - RNA is made of a single
sequence is transformed polynucleotide strand:
(transcribed) into mRNA (messenger),
Structure of a nucleotide
tRNA (transfer) and rRNA
(ribosomal). DNA is the template 3 components:
copied into RNA by base pairing. G
A Pentose sugar
with C; A with U.
- This is a 5 carbon sugar
Protein: functional products of genes;
- sugar in DNA is deoxyribose
executes cellular functions
- The sugar in RNA is ribose

A Phosphate group

- they link the sugar on one

nucleotide onto the phosphate
of the next nucleotide to make
a polynucleotide
A Nitrogenous base - the ratio of the two will always
be constant within a DNA
- In DNA the four bases are:
molecule.
Thymine, Adenine, Cytosine,
- one strand of DNA will always
Guanine
be an exact complement of
- In RNA the four bases are:
the other as far as purines and
Uracil, Adenine, Cytosine,
pyrimidines go.
Guanine
Sugar phosphate bonds
Two types
- (backbone of DNA)
Purines and pyrimidines are
- Nucleotides are connected to
composed of carbon and nitrogen
each other via the phosphate
rings, that make up nucleic acids the
on one nucleotide and the
building blocks of DNA and RNA.
sugar on the next nucleotide.
Pyrimidines (Thymine T, Cytosine C, - Each nucleotide is linked to the
Uracil U) – one ring next by covalent bonds
between their phosphates and
- has just six members and
sugars.
nitrogen atoms
- smaller James Watson (L) and Francis Crick
(R) - they built of the structure of
Purines ( Adenine A, Guanine G) - two
DNA
rings
DNA Strands - Two strands that
- nine membered molecule with
complement each other.
four nitrogen atoms
- bIGGER - Antiparallel - does not go in
the same direction.
Complementary pairing - purines
always bind with pyrimidines.

Chargaff’s Rule - named after Irwin

Chargaff, who first noticed it.
 4. Self replication: DNA has the
ability to make copies of itself.

Nature of the Genetic Material

Property 1 it must contain, in a stable

form, information encoding the
organism’s structure, function,
DNA Replication development and reproduction

Property 2 it must replicate

accurately so progeny cells have the
same genetic makeup

Property 3 it must be capable of

Functions of DNA some variation (mutation) to permit
evolution.
1. DNA directs the machinery of a
cell to make specific proteins , Lesson 5: DNA Replication and
and, therefore, DNA indirectly Protein Synthesis
controls all of the functioning
MITOSIS - equational cell division
of all living things
that produces daughter cells which
2. DNA stores the hereditary
are identical or clones of the original,
information of an individual.
mother cell.
Stem Cell – A single cell that
can replicate itself or - This ensures that every cell of
differentiate into many cell the body has the same genetic
types. content.
3. DNA has the ability to mutate
DNA Replication - DNA strands
(change). This allows for new
separate and serve as templates for
characteristics and abilities to
the production of new DNA
appear which may help an
molecules.
individual to survive and
reproduce (EVOLUTION). - Semi conservative replication -
is the process in which the
 original strands of DNA remain Dispersive Replication:
intact and act as templates for
the synthesis of duplicate
strands of DNA.
- Occurs and never leaves inside
the nucleus.
- Replication happens during
Interphase.

Eukaryotic Cell Cycle – DNA

Replication has to happen before the
cell can divide so both cells have 1. One copy of a DNA molecule
DNA. will split apart to make two
Speed of DNA replication: complete copies of itself. Each
new DNA molecule is made up
3,000 nucleotides/min in human of half of the old molecule and
half of a new molecule.
30,000 nucleotides/min in E.coli
2. Base pairing is maintained; A to
Accuracy of DNA replication: T, G to C
3. New DNA molecules are
Very precise (1 error/1,000,000,000
produced in the 5’ to 3’
nt)
direction.
Conservative Replication: one is 4. Semi - discontinuous :The
Original and second is old double leading strand is synthesized in
helix. a continuous manner (5’ to 3’)
while the lagging strand is
Semiconservative Replication:
produced discontinuously in
TWO Original and new in one double short stretches called Okazaki
helix. fragments.
 in the 5’ to 3’
direction.
- This sort of
replication is
Called
continuous.
ROLE OF ENZYMES

They first “unzip” a molecule of DNA

by breaking the hydrogen bonds
Replication fork - the open area of
between base pairs.
DNA where replication or
transcription can take place. ENZYMES

Leading Strand Lagging Strand Topoisomerases - a DNA gyrase,

A short piece of Numerous RNA work on double stranded DNA to
RNA called a primers are made relive or induce supercoils
primer (produced by the primase
by an enzyme enzyme and bind Helicase - unzipping enzyme, unwinds
called primase) at various points the DNA by breaking the hydrogen
comes along and along the lagging bonds between complementary
binds to the end strand. bases
of the leading -Chunks of DNA,
strand. The called Okazaki Single strand binding proteins (SSB) -
primer acts as fragments, are bind to the newly separated
the starting point then added to individual DNA strands, keeping the
for DNA the lagging
strands separated by holding them in
synthesis. strand also in the
-DNA polymerase 5’ to 3’ direction. place so that each strand can serve as
binds to the -This type of template for new DNA synthesis.
leading strand replication is
Primase - a type of RNA polymerase
and then ‘walks’ Called
along it, adding discontinuous as the initializer, it makes the primer, a
new the Okazaki short RNA sequences (5 10
complementary fragments will ribonucleotides long).
nucleotide bases need to be joined
(A, C, G and T) to up later. RNA primer - serves as starter
the strand of DNA sequence for DNA polymerase III
 - Only one RNA primer is 2. COMPLEMENTARY BASE
required for the leading strand PAIRING : Complementary
- RNA primers for the lagging nucleotides move into position
strand depend on the number to bond with the
of Okazaki fragments. complementary bases on the
DNA chain.
DNA polymerase - builder, replicates
3. FORM NEW SUGAR
the DNA molecules to actually build a
PHOSPHATE BACKBONE : The
new strand of DNA, works in pairs to
nucleotides join as the sugars
create two identical DNA strands
and phosphates bond to form a
from one original DNA strand.
new backbone. This process
occurs due to the enzyme DNA
POLYMERASE which also
checks for mistakes as it goes.
4. This process continues along
the primary chain until we
have 2 IDENTICAL STRANDS of
DNA molecules.

DNA Ligase – seals the ‘nicks’

between Okazaki Fragments.
Converting them to a continuous
strand of DNA.

Steps to DNA Replication

Errors = Mutation
1. UNZIPPING : The DNA
molecule Unzips as the Mutations - can occur naturally or
hydrogen bonds between the through environmental factors.
base pairs are broken . The Environmental mutagens include
enzyme HELICASE causes this some chemicals (food additives,
unzipping to occur. pesticides, plastics) and radiations (X
rays to UV light).
2) A gene mutation - is a change of
one or more nucleotides in a single
gene. There are 3 types.

a) Addition - one extra nucleotide

base is added. This will also change
the entire amino acid sequence of
the protein, so SHAPE and FUNCTION
of protein are altered. Serious

b) Deletion- one nucleotide base is 3. Chromosomal mutations : a

left out. All of the amino acids after a mutation of all or part of a
deletion will be wrong, so SHAPE and chromosome. These affect many
FUNCTION of protein are altered. genes
Serious Example #1
c) Substitution - when single bases or : crossing over where one part of a
short pieces are replaced with one chromosome changes places with
another. not as serious another.

Cri du Chat Syndrome

("Cry of the cat" in French) is a

genetic disorder caused by the loss or
misplacement of genetic material
from the 5th chromosome.

It was first identified in 1963 by

Professor Lejeune. He described the
syndrome after the sound that many
of the babies and young children
make when crying.

Example #2
:non disjunction = extra
chromosomes or missing
chromosomes due to mistakes made
during meiosis.

Down Syndrome - occurs in approx. 1

in 700 births in Canada. A person
with Down Syndrome has 47 3 major types of RNA
chromosomes in each cell instead of
46. Messenger RNA (mRNA) carry a

Klinefelter syndrome - had enlarged message base in the DNA

breasts, sparse facial and body hair, Transfer RNA ( tRNA ) transfer the
small testes, and an inability to
produce sperm. message

By the late 1950s, it was discovered Ribosomal RNA ( rRNA ) component

that men with Klinefelter syndrome, of the ribosome.
had an extra sex chromosome, XXY The Central Molecular Dogma of
instead of the usual male Molecular Biology states that DNA
arrangement, XY. MAKES RNA MAKESPROTEINS
TURNER’S SYNDROME - A disorder Replication Transcription
that results from a non disjunction of New DNA is formed New RNA is
the X chromosomes during meiosis = formed
X0 instead of XX. Individuals are short DNA DNA
and stocky; also sterile. DNA hybrid complex RNA hybrid
complex
TRANSCRIPTION AND TRANSLATION DNA polymerase RNA
enzyme polymerase
enzyme
Primer is required Primer not
required
Deoxyribonucleotid Ribonucleotide
es used s used
Entire genome is Very small
 copied portion of  Only one strand is transcribed.
genome The strand that contains the
transcribed gene is called the sense strand
Proofreading No , while the complementary
proofreading
strand is the antisense strand
Genetic information Information is
is transferred  The mRNA produced in
inherited from gene to transcription is a copy of the
protein sense strand, but it is the
antisense strand that is
transcribed.
Transcription is the process by which
DNA is copied ( transcribed ) to
mRNA, which carries the information
needed for protein synthesis.

mRNA is a product of transcription.

- Starts in the nucleus.

DNA matches with corresponding RNA polymerase - joins the

RNA bases with help of enzymes ribonucleotides together to form a
pre messenger RNA molecule that is
Formation of the pre mRNA
complementary to a region of the
 The mechanism of antisense DNA strand.
transcription has parallels in
It builds an RNA strand in the 5’to
that of DNA replication.
3’direction.
 As with DNA replication,
partial unwinding of the double - Transcription ends when the
helix must occur before RNA polymerase enzyme
transcription can take place, reaches a triplet of bases that
and it is the RNA polymerase is read as a "stop" signal. The
enzymes that catalyze this DNA molecule re winds to re
process. form the double helix.
EXONS - code for amino acids and subsequent translation by the
collectively determine the amino acid ribosome.
sequence of the protein product.

- Are represented in final mature

mRNA molecule.

INTRONS - Are portions of the gene

that do not code for amino acids, and Molecular Components of
are removed (spliced) from the Transcription
mRNA molecule before translation. RNA synthesis is catalyzed by RNA
Alternative splicing polymerase , which pries the DNA
strands apart and hooks together the
- individual exons are either RNA nucleotides
spliced or included, giving rise
to several different possible - The RNA is complementary to
mRNA products. the DNA template strand
- Each mRNA product codes for a - follows the same base pairing
different protein isoform; these rules as DNA, except that uracil
protein isoforms differ in their substitutes for thymine.
peptide sequence and - RNA polymerase builds an RNA
therefore their biological strand in the 5' to 3' direction,
activity. adding each new nucleotide to
- It is estimated that up to 60% the 3' end of the strand.
of human gene products The DNA sequence where RNA
undergo alternative splicing. polymerase attaches is called the
Spliceosomes promoter ; in bacteria, the sequence
signaling the end of transcription is
- An enzyme responsible for called the terminator
removal 0f n0ncoding
segments (introns) from pre The stretch of DNA that is transcribed
messenger RNAs (pre mRNAs), is called a transcription unit.
a process critical for the Synthesis of an RNA Transcript
maturation of mRNAs for
The three stages of transcription

Initiation - Promoters signal the

transcriptional start point and usually
extend several dozen nucleotide pairs
upstream of the start point

Transcription factors mediate the

binding of RNA polymerase and the
initiation of transcription

The completed assembly of

transcription factors and RNA
polymerase II bound to a promoter is
called a transcription initiation
complex

A promoter called a TATA box is

crucial in forming the initiation
complex in eukaryotes

Elongation – As RNA polymerase

moves along the DNA, it untwists the Termination - the ending of
double helix, 10 to 20 bases at a time transcription, and occurs when RNA
polymerase crosses a stop
- Transcription progresses at a
(termination) sequence, AATAAA , in
rate of 40 nucleotides per
the gene. The mRNA strand is
second in eukaryotes
complete, and it detaches from DNA.
- A gene can be transcribed
simultaneously by several RNA The RNA transcript is released 10- 35
polymerases nucleotides past the sequence.
- Nucleotides are added to the
TRANSLATION OR PROTEIN
end of the growing RNA
SYNTHESIS
molecule
The mRNA formed in transcription is Ribosomes (large and small
transported out of the nucleus, into subunits) -
the cytoplasm, to the ribosome (the
cell's protein synthesis factory).

Mature mRNA molecule is used as a

template to assemble a series of
amino acids to produce a polypeptide
with a specific amino acid sequence.

Messenger RNA is not directly

involved in protein synthesis–
transfer RNA ( tRNA ) is required

The process by which mRNA directs

protein synthesis with the assistance
of tRNA is called translation

The ribosome is a very large complex

of RNA and protein molecules.

Each three base stretch of mRNA

(triplet) is known as a codon , and
one codon contains the information
for a specific amino acid.

As the mRNA passes through the

ribosome, each codon interacts with
the anticodon of a specific transfer
RNA ( tRNA ) molecule by Watson
Crick base pairing.

Translational Components
 Messenger RNA (mRNA) - An
untranslated region (or UTR) refers
to either of two sections, one on each
side of a coding sequence on a strand
of mRNA.

If it is found on the 5' side, it is called

the 5' UTR (or leader sequence), or if
it is found on the 3' side, it is called
the 3' UTR (or trailer sequence).

-mRNA is RNA that carries

information from DNA to the
ribosome, the site of protein
synthesis (translation) within a cell.
The mRNA is initially transcribed from
the corresponding DNA sequence and
Two types: 70S and 80S having two then translated into protein.
subunits. The “S” stands for Svedberg
unit, the rate of sedimentation and However, several regions of the
centrifugation of RNA fragments. mRNA are usually not translated nto
protein, including the 5' and 3' UTRs.
Ribosome has three slots for tRNAs:
the A site, P site, and E site. tRNAs
move through these sites (from A to Transfer RNA (tRNAs) - Molecules of
P to E) as they deliver amino acids tRNA are not identical
during translation.
- Each carries a specific amino
The A site - incoming aminoacyl tRNA acid on one end
molecules bind, and the P site is - Each has an anticodon on the
where the growing polypeptide chain other end; the anticodon base
is usually found. pairs with a complementary
codon on mRNA
 - A tRNA molecule consists of a - The genetic code includes 64
single RNA strand that is only codons
about 80 nucleotides long - Most codons code for specific
- Flattened into one plane to amino acids. There are four
reveal its base pairing, a tRNA special codons: one that codes
molecule looks like a cloverleaf for “start” AUG and the three
that code for “stop” UGA,
UAG, UAA.

“Wobble”Pairing

- In bacteria, there are 30 40

tRNAs with different
anticodons. In animal and plant
cells, about 50 different tRNAs
are found.
- There are 61 codons coded for
Amino Acids - tRNAs carry amino acids.
“activated” amino acids - Suppose each codon can pair
- Amino acid activation also with only a unique anticodon,
known as aminoacylation or then 61 tRNAs would be
tRNA charging, refers to the needed.
attachment of an amino acid
to its tRNA.
- An aminoacyl tRNA synthetase
( aaRS or ARS), also called tRNA
ligase, is an enzyme that
attaches the appropriate amino
acid onto its tRNA.

Codons - The nitrogenous bases are

grouped into three letter codes
called codons.
 with the large unit of the ribosome
complex and an initiation tRNA
molecule.

2. Elongation
Release Factor - Subsequent codons on the mRNA
- A protein that allows for the molecule determine which tRNA
termination of translation by molecule linked to an amino acid
recognizing the termination bonds to the mRNA.
codon or stop codon in an An enzyme peptidyl transferase links
mRNA sequence. the amino acids together using
- They are named so because peptide bonds.
they release new peptides
from the ribosome. The process continues, producing a
chain of amino acids as the ribosome
STEPS IN TRANSLATION moves along the mRNA molecule.
1. Initiation A charged transfer RNA molecule
- The small subunit of the ribosome binds to the A site and a peptide
binds at the 5’ end of the mRNA bond forms between its amino acid
molecule and moves in a 3’ direction and the one attached to the transfer
until it meets a start codon (AUG). It RNA molecule at the P site.
then forms a translation complex
The complex slides down one codon The purpose of translation is to
to the right where the now produce polypeptides quickly and
uncharged transfer RNA molecule accurately
exits from the E site and the A site is
After dissociation, the polypeptide
open to accept the next transfer
may need to be modified before it is
RNA molecule.
ready to function.
Elongation will continue until a stop
Modifications take place in different
codon is reached.
organelles for different proteins

3. Termination - terminated when

the ribosomal complex reached one
or more stop codons (UAA, UAG,
UGA)

- A release factor binds to the A site

at a stop codon and the polypeptide
is released from the transfer RNA in
the P site. The entire complex
dissociates and can reassemble to
begin the process again at initiation.
 Bt endotoxin - Results in the death of
pests that feed on these plants like
the corn borer larvae.

- The toxin has been shown

to be selective for
Lepidoptera larvae.
- larvae and is non toxic to
humans, mammals, fish and
birds.

The same technology has been

applied in the Philippines for the
development of Bt Eggplant.

Golden Rice – modified with daffodil

genes to more beta-carotene, which
the body converts to vitamin A.

Flavr Savr Tomatoes – (“Flavor

Savor”)first genetically modified
organism that was licensed for
human consumption.
Genetic Engineering Tomatoes modified by the removal of
BT Corn - developed to incorporate genes. Softening, and slow spoiling.
the production of a toxin (Bt Polygalacturonase - A gene for an
endotoxin) from Bacillus thuringensis enzyme that causes the degradation
in corn plants. of pectin in the cell walls. Softens the
- Modified with bacterial fruit as it ripens.
insecticide gene so that it Aqua Advantage Salmon – modified
produces insect toxins, with growth hormone in order to
protecting from pest species. grow.
Glow in the dark animals – modified - They cannot control what
with genes for flourescent proteins genes are passed.
will glow in the dark.
Three types of artificial
selection:

Genetic Engineering - Addition, a. Selective breeding: When

deletion, or manipulation of a single animals with desired
trait in an organism. characteristics are mated to
produce offspring with
- Changing the DNA in living
those desired traits.
organisms to create
b. Hybridizations : Two
something new.
individuals with unlike
- Bacteria can be engineered
characteristics are crossed
to produce human proteins
to produce the best in both
- Human genes can be
organisms.
inserted into other animals.
c. Inbreeding: breeding of
Transgenic Organisms - Organisms organism that is genetically
altered by genetic engineering. similar to maintain desired
traits.
Gene transfer - moving a gene from
Risk: since both have the
one organism to another.
same genes, the
'Trans --' means 'crossing from one chance that a baby will get a
place to another‘ recessive genetic
disorder is high.
The ' genic' bit means genes
Variation: difference between
Examples of Transgenic Organisms
individuals of a species.
GMO genetically modified organism
2. Cloning: creating an organism
GEO genetically enhanced organism that is an exact genetic copy of
another. Clone: group of cells or
Genetic engineering techniques:
organisms that are genetically
1. Artificial selection - : breeders identical as a result of asexual
choose which organism to mate. reproduction.
Dolly: the first mammal cloned. Step 3: The nucleus of the
diploid body cell is put into the
- (5 July 1996 - 14 February
egg.
2003)
- using the process of nuclear :This egg no longer needs to be
transfer. fertilized since it has all 46
chromosomes.
SOMATIC CELL NUCLEAR
TRANSFER - Technique for Step 4: The egg is then charged
cloning in which the nucleus of with electricity to start mitosis.
a somatic cell is transferred to
Step 5: Its then put into a
the cytoplasm of an enucleated
surrogate mother so it can
egg. Then, the cytoplasmic
grow.
factors the nucleus to become
a zygote. Its going to be genetically
identical to the parent of the
Eggs are haploid: half the
body cell.
chromosomes, 23 in humans

Body cells are diploid : Two

sets of chromosomes, one
from mom and one set from
dad 46 in humans.

Steps:

Step 1: An egg is removed from Benefits of cloning:

a female human.
1. You can make exact copies
:The nucleus of the egg is of organisms with strong
removed and is thrown away. traits.

Step 2: A body cell is removed 2. Increase food supply

from another person.
3. Medical purposes: clone
:The nucleus of the body cell is
organs for transplants.
removed.
 4. Bring back or Stop species Biotechnology: New technological
from going extinct. field called (technology of life.)

Risks of cloning: 5 Stages involved in Recombinant

DNA
1. Decreases genetic diversity
2. If one of your clones gets a
disease, they all get it: same
immune system.
3. Inefficient: high failure

rate: 90%+

4. Expensive

3. Gene splicing/ Recombinant

1. Isolation
DNA: DNA trait is cut out of one
organism and put into another (a) Isolation of a specific gene from
organism. donor e.g. human

Benefits: - Cells broken open using chemicals

and enzymes. Donor DNA is
- Insulin is cheaper extracted.
- There are no side effects
because it is human insulin. - Genetic probe added. The probe will
- Once used pig insulin but bind to a complementary DNA
there are side effects and it sequence by base pairing. Identifying
is more expensive. the presence and location of the gene
of interest
Transformation: Gene from one
organism is transferred to different - Reveals position of the gene of
organism. interest

Transgenic organisms: The organisms

that have DNA transferred to them
(b) Isolation of plasmid from a
bacterial cell

2. Cutting DNA Ligase -

Restriction enzymes act as molecular

scissors and cut DNA at specific sites
called restriction sites.

The cut ends have sticky ends. The

same restriction enzymes cut the
DNA from the plasmid also revealing
sticky ends.
Ligation - rejoining cut fragments of
DNA and forming artificial
recombinant molecules.

3. Ligation and Insertion

Ways Plasmids may be Introduced

into Host Organisms
Biolistics - In this technique, a “gene - The rapid rise and drop of
gun” is used to fire DNA coated temperature is believed to
pellets on plant tissues. increase and decrease the
pore.
- Cells that survive the
- The cells that took up the
bombardment are able to
plasmids acquire new traits
take up the expression
and are said to be
plasmid coated pellets and
“transformed”.
are able to express the
designed protein. Electroporation - the expansion of
the membrane pores is done through
Plasmid insertion by Heat Shock
an electric “shock”.
Treatment - is a process used to
transfer plasmid DNA into bacteria. - Commonly used for
insertion of genes into
- The target cells are pre-
mammalian cells.
treated before the
procedure to increase the 4.Transformation
pore sizes of their plasma
- Recombinant DNA introduced into
membranes.
bacterial cell.
- This pretreatment is said
tomake the cell - The plasmid is introduced into
“competent”. bacteria via process called
- Then, they are incubated transformation , and bacteria
with the desired plasmid at carrying the plasmid are selected
about 4 C for about 30min. using antibiotics.
The plasmids concentrate
near the cells during this
time.
- Afterwards, a “Heat Shock”
is done on the plasmid cell
solution by incubating it at
42 C for 1 minute then back
to 4 C for 2 minutes. Methods to screen recombinant cells
Selection of plasmid DNA containing
cells - A selection marker within the
inserted plasmid DNA sequence
allows the selection of
“transformants ”.

- Only “transformed” cells

survive in the presence of
the antibiotic.
- Plating the plasmid cell 5. Expression - Bacterial cell
solution on antibiotic reproduces by Binary Fission
containing media will select - Bacterial cell produces the
for these “transformants ” polypeptide
and only allow plasmid
containing cells to grow and - Coded for by the donor DNA
propagate into colonies. - Bacteria with the correct plasmid
are used to make more plasmid DNA
or, induced to express the gene and
Selection of transformed cells with make protein.
the desired gene - Certain inserted
genes within the plasmids provide Expression - is getting the organism
visible proof of their presence. Some with the recombinant DNA to
inserted genes also produce colored produce the desired protein.
(e.g. chromogenic proteins) or When the protein is produced in
fluorescent products (e.g. GFP) that large amounts it is isolated and
label the colonies/cells with the purified by biochemical process.
inserted gene.
- The bacteria serve as
miniature “factories,"
churning out large amounts
of protein. For instance, if
our plasmid contained the
human insulin gene, the
 bacteria would start (transgenic) animals are
transcribing the gene and mostly used to make human
translating the mRNA to proteins that have
produce many molecules of medicinal value. The protein
human insulin protein. encoded by the transgene is
secreted into the animal's
Summary of steps
milk, eggs or blood, and
1. Cut with restriction enzymes then collected and purified.
2. Ligase bonds sticky ends
Tracy the Sheep
together
One of the first mammals engineered
Animals used in GE
successfully for the purpose of
The human gene to clot blood has pharming.
been inserted into the DNA of sheep
- Born in 1990 and created by
Sheep produce human clotting factor scientists led by British
needed for Haemophiliacs in their developmental biologist Ian
milk Wilmut at Roslin Institute in
Scotland. Tracy was created
Goats produce a protein to treat
from a zygote genetically
emphysema
engineered through DNA
Applications (Microorganisms) injection to produce milk
containing large quantities
Humulin – used by diabetics
of the human enzyme alpha
Applications of Genetic Engineering 1 antitrypsin, a substance
used to treat cystic fibrosis
Pharming Biopharmaceuticals - Gene
and emphysema.
pharming is a technology that
scientists use to alter an animal's own Xenotransplantation is the
DNA, or to splice in new DNA, called a transplantation of living cells, tissues
transgene, from another species. or organs from one species to
another.
- In pharming, these
genetically modified
Porcine islet transplants are being - 25% of all corn is like this.
investigated for use in type 1
B. Venomous cabbage - gene from a
diabetes due to the shortage of
scorpion tails inserted into cabbage.
human islet cells.
- Cabbage now produces that
1. Transgenic (GMO) animals : genes
chemical.
inserted into animals so they produce
what humans need. - To limit pesticide use while still
preventing insects from damaging
To improve the food supply:
crops.
A. Transgenic cows : gene
Corporations state the toxin is
inserted to increase milk
modified so it isn’t harmful to
production.
humans.
B. Spider goat: gene from spider
inserted into goat. C. Banana vaccines - Virus is injected
- Goats make silk of the into a banana, the virus DNA
spider web in their milk. becomes part of the plant.
- Flexible, stronger than steel.
As the plant grows, it produces the
Used in bulletproof jackets.
virus proteins but not the disease
C. Glow in the dark cats -
part of the virus.
Scientist used a virus to insert
DNA from jellyfish When people eat a bite, their
- The gene made the cat immune systems creates antibodies
produce a fluorescent to fight the disease just like a
protein in its fur. traditional vaccine.

2. Transgenic bacteria: gene inserted Vaccines for hepatitis and cholera

into bacteria so they produce things
Vaccines
humans need.
- Genetically engineered
3. Transgenic plants: plants are given
microbes can be used to
genes so they meet human needs.
produce the antigens
A. Transgenic corn: given a gene so needed in a safe and
corn produces a natural pesticide. controllable way.
 - The use of genetically Cystic fibrosis - the best known
modified yeast cells to disease where gene therapy has been
produce a vaccine against tried.
the hepatitis B virus has
4. Gel electrophoresis : a technique
been a major success story.
used to compare DNA from two or
Plants more organisms.

Weedkiller resistant crops Why compare DNA:

- Weeds die but the crops 1. Find the baby’s father/mother

survive
2. Who committed a crime.
Vitamin A in Rice
3. How closely species are related
- The gene which produces
How is electrophoresis done?
vitamin A was taken from
daffodils and put into rice to A. The DNA is cut into fragments with
help prevent blindness. a restriction enzyme.

Interferon - can fight virus infection B. The cut DNA is then put into the
and som cancers. wells of a machine filled with gel.

Gene Therapy - It involves modifying The gel is spongy and the DNA
human DNA either to repair it or to squeezes through the pores.
replace a faulty gene.
The machine is plugged in and the
- The idea of gene therapy is fragments get separated based on
to overcome the effects of a their size. The smaller fragments
mutation which causes a move further than the large.
genetic disease.
5. Polymerase Chain Reaction
- when disease causing genes
Amplification
are cut out and good gene
- Once a desired trait is
are inserted.
chosen, information must
be acquired for either its
 detection or expression in a of the generated ssDNA strand
given organism. through the binding o
- A technique that allows the complementary bases to the
detection of specific genes template strand (~72 C).
in target organisms is called
PCR. - A typical PCR experiment
- The method uses thermal uses about 35 cycles of
cycling or the repeated amplification.
heating and cooling of the
reaction for DNA melting
and replication. As PCR
continues, the “new” DNA is
used as a template for
replication and a chain HISTORYOF LIFE ON EARTH
reaction ensues. The Age of Earth
- Protein engineering,
 When earth formed 4.6 billion years ago
- cloning, forensics (DNA it was a fiery ball of molten rock
fingerprinting), paternity
 Eventually the molten rock cooled and
testing, the diagnosis of formed the crust
hereditary and/or infectious
Early Earth 4.4 b.y.
diseases, and for the
analysis of environmental  As Earth cooled, water vapor in the
atmosphere condensed and rained out to
samples. form oceans - maybe as early as 4.4 b.y.
ago.
PCR uses repeated cycles of
Early Life 3.8 b.y.
incubation
 Near the end of the intense
At different temperatures to promote bombardment period, about 3.8 b.y. ago,
the unwinding of the DNA template Earth still was wracked by meteorite
impacts and volcanic eruptions. It was a
(~95 C); the annealing of a primer (a
tough place to make a living.
~20bp oligonucleotide sequence
The Age of Earth
(recall RNA primers in DNA
replication) onto the ssDNA template  •Most scientists think that life arose out
of these early oceans •Rocks have been
strand (~54 60 C); and the extension
 dated back, so this supports the idea of a  For example, earthquakes, floods, volcanic
gradual change. eruptions, and asteroid impacts can cause
sudden changes to Earth’s surface.
How have geologists described the rate of
geologic change? WHAT WAS THE EARTH LIKE MILLION
OF YEARS AGO?
 Some early scientists used
catastrophism to explain geologic A. Covered with thick blanket of ice
changes on Earth.
B. Lots of volcanoes and high mountains
 Catastrophism is the principle that
states that all geologic change occurs C. Large organisms roamed the land
suddenly. D. The atmosphere did not have high
oxygen content
 Supporters of catastrophism thought that
Earth’s features, such as mountains and E. Asteroids/meteors frequently hit the
seas, formed during sudden events surface
called catastrophes.
F. A little bit warmer
How have geologists described the rate of
geologic change? G. Plants were bigger

 About 250 years ago, James Hutton H. Humans were not yet around
established a principle that is now known as
WHEN DID MAN FIRST APPEAR ON
uniformitarianism.
EARTH?
 Uniformitarianism is the idea that the same
 Life on Earth arose around 3.5 billion years
geologic processes that shape Earth today
ago.
have been at work throughout Earth’s
history.  Man could have first appeared about 100-
500 thousand years ago as shown by
 The principle also states that the average
artifactual evidences in various sites.
rate of geologic change is slow and has
remained relatively constant over time. Earth History: Geologic Time
How have geologists described the rate of Arche Crygen Edlacaran Cambr Ordovi
geologic change? an ian Period ian cian
Era Period 635 M – Period Period
 Today, geologists realize that neither 3.8 B 850 M 545 M 545 M 495 M
uniformitarianism nor catastrophism – 2.5 – 635 – 495 – 443
accounts for all geologic change. B M M M
years
 While most geologic change is gradual and ago
uniform, catastrophes do cause some Siluri Devoni Carbonife Permi Triassic
geologic change. an an rous an Period
Perio Period Period Period 248 M
d 417 M 354 M – 290 M – 205
443 – 354 290 M – 248 M
M– M M  The largest unit of geologic time is an
417 eon.
M
Jurass Cretace Paleocene Eocen Oligoce  Earth’s 4.6-billion-year history is
ic ous Epoch e ne divided into four eons: the Hadean,
Perio Period 65 – 54.8 Epoch Epoch Archean, Proterozoic, and Phanerozoic.
d 142 – M 54.8 – 33.7 –
205 65 M 33.7 23.8 M  The Hadean, Archean, and
M– M
142 Proterozoic eons together are called
M Precambrian time.
Mioc Pilocen Pleistoce Holoc
ene e ne Epoch ene  Precambrian time makes up almost 90
Epoc Epoch 2.6 M – Epoch percent of Earth’s history.
h 5.3 – 11. 7 11.7
23.8 2.6 M thousand thousa  Eons may be divided into smaller units
– 5.3 nd – of time called eras.
M presen
t  Extinction events and appearance of
new life forms characterized the
divisions among Eras.
What is the Earth’s time scale?
 The Phanerozoic Eon, the present eon,
 The Geological time scale is a record of the
is divided into three eras: the Paleozoic,
life forms and geological events in Earth’s
Mesozoic, and Cenozoic.
history.
 Each era is subdivided into a number of
 Scientists developed the time scale by
periods.
studying rock layers and fossils worldwide.
 The periods of the Cenozoic, the present
Geological Time Scale
era, are further divided into epochs.
 Timeline that organizes the events in Earths
Eons divided into Eras: –PreCambrian,
history.
Paleozoic, Mesozoic, Cenozoic
 Earth is estimated to be around 4.6 billion
 Ceno - recent
years old based on the rock and fossil record
 Meso - middle
 More complex organism such as land plants
and fish evolved only within the last 500  Paleo - ancient
million years.
 Zoic – life
How do geologists use the geologic time scale?
1. EON- largest division of the geologic
 The geologic time scale divides Earth’s time scale; spans hundreds to thousands
geologic history into intervals of time of million of years ago (mya)
defined by major events or changes on
Earth.
 2. ERA- division in an Era that span time  The explosion created the complexity of
periods of tens to hundreds of millions multi-celled organisms in a relatively short
of years time frame of 5 to 10 million years.

3. PERIOD- a division of geologic history  This explosion also created most of the
that spans no more than one hundred major extant animal groups today.
million years
What were some defining events of the
4. EPOCH- the smallest division of the Paleozoic Era?
geologic time scale characterized by
distinctive organisms  The Paleozoic Era began about 540 million
years ago. The supercontinent Pannotia was
Geological Time Scale (GTS) breaking up and the supercontinent
Pangaea began forming.
A. Four eras – Precambrian, Paleozoic,
Mesozoic, Cenozoic  Life diversified quickly and dramatically
during the Cambrian Explosion, during
B. Periods under the Paleozoic era –
which most major groups of organisms first
Cambrian, Ordovician, Silurian,
evolved.
Devonian, Carboniferous, Permian
 The era ended about 250 million years ago
C. Periods under the Mesozoic era –
with a huge mass extinction event.
Triassic, Jurassic, Cretaceous

D. Periods under the Cenozoic era –  During the Cambrian Explosion, new
Tertiary and Quarternary species evolved rapidly in Earth’s shallow
seas.
What were some defining events of Precambrian
time? What were some defining events of the
Mesozoic Era?
 Precambrian time began with the formation
of Earth about 4.6 billion years ago.  During the Mesozoic Era, which began
about 250 million years ago, Pangaea
 Massive supercontinents, the first oceans, began breaking up.
and the early atmosphere formed during this
time.  The Atlantic Ocean began to open up,
the MidAtlantic Ridge formed, sea
 Toward the end of Precambrian time, much levels rose, and shallow seas covered
of Earth’s land surfaces were located near much of the land.
the poles and covered in ice.
 Along the western edge of North
CAMBRIAN EXPLOSION America, tectonic activity began to fold
Earth’s crust, forming mountains. The
 It is the belief that there was a sudden, climate was likely warm, as periods of
apparent explosion of diversity in life heavy volcanism added carbon dioxide
forms about 545 million years ago. to the atmosphere.
  Life during the Mesozoic was - 3.8 B to 2.5 Billion years ago
dominated by dinosaurs. The few
mammals were very small. Fossil Record – Archean

 A mass extinction event about 65 - 3.5 b.y.: The oldest known fossils are chains
million years ago marked the end of the of prokaryotic cells from a chert in W.
era, and the end of dinosaurs. Australia

What have been some defining events of the Fossil Record Precambrian
Cenozoic Era?  Stromatolites are layers of calcium
• The Cenozoic Era began about 65 million carbonate that form in warm, shallow seas
years ago with the Cretaceous mass extinction by the activities of photosynthetic bacteria.
and continues to the present.
 Fossil stromatolites > 1.5 b.y. are evidence
• Greenland split apart from North America and of microbial activity during the Proterozoic
Europe, and the continents assumed their current and Archean (as far back as 3.0 b.y. or
positions. earlier).

 The Indian subcontinent collided with CRYOGENIAN PERIOD

Eurasia to form the Himalayas. The
- Succession of harsh ice ages waxed and
collision of Africa and Europe resulted in
waned
the Alps.
- “Snowball Earth”
The Cenozoic Era is divided into two periods:
the Tertiary and the Quaternary. The latter - Glaciations reached the equator
stretches from about 2.6 million years ago to the
present. - Life consisted of tiny organisms: fungi,
plants, animals and kelps
 The Quaternary has been characterized by
an ice age, with much of Europe, North - 850 t0 635 Million years ago
America, and Asia having been covered in
EDIACARAN PERIOD
thick sheets of ice.
- “Vendian”
 The evolution of modern humans occurred
during the late Quaternary. - Final stage of pre-Cambrian

ARCHEAN ERA - Life then was soft-bodied; no bones, shells,

teeth or hard parts
- Life first arose on earth
- Remains from this period were rare
- No continents; small island in a shallow
ocean - First ever burrowing animals

- Vast amound of carbon dioxide; no - Only fossils were burrows

rising of temperature
- Name is from Ediacara Hills, AUS
- Low oxygen levels
- 635 to 545 Million years ago - Animals swam, crawled, burrowed, hunted,
and defended themselves
Fossil Record Proterozoic
- Evolved hard parts, ex. Shells
 About 1.4 b.y.a. - oldest eukaryotes By
1.0 b.y.a. - eukaryotes common 600 - Fossils at the Burgess Shale site
m.y.
- No life on land and little or none in
 Ediacara fauna: oldest fossils of larger, freshwater; sea was the center of living
multicellular, softbodied marine activity
animals.
- 545to 495 million years ago
 Named for Ediacara Hills, Australia.
Fossil Record Cambrian
 Fossil Record Proterozoic
- 545-505 m.y.a. - beginning of period of
 Mawsonia spriggi - a floating, disc- great diversification:
shaped animal like a jellyfish, 13 cm - Higher atmospheric oxygen affected skeletal
across. biochemistry and supported larger
Fossil Record - Late Proterozoic organisms.

 Ediacaran Fauna are still poorly - Ozone developed to level where it blocked
understood. ultraviolet radiation.

- Eukaryotes invented sexual reproduction.

 Some are simple blobs, others are like
jellyfish, worms, or softbodied relatives - Hard parts appeared.
of the arthropods.
- Ozone developed to level where it blocked
 They appear worldwide in strata about ultraviolet radiation.
600 m.y. old, suggesting a relatively
sudden explosion of soft multicelled - Eukaryotes invented sexual reproduction.
forms.
- Hard parts appeared.
Fossil Record - Late Proterozoic
- Fossil Record Cambrian
 Plants: Land plants probably evolved from
- Trilobite, Utah
green algae about 600 m.y. ago. Life on
land may have looked like this. In the seas, - Soft-bodied arthropod
bacteria and green algae were common at
the end of the Precambrian. - 545-505 m.y.a.: Hard external skeletons
protected trilobites, clams, snails, and sea
 Green algae urchins from predators.

CAMBRIAN PERIOD - Soft-bodied animals diversified from

Ediacaran fauna into the Burgess Shale
- Explosion of abundant and diverse life
fauna.
forms
- Gills, filters, efficient guts, circulatory Fossil Record – Silurian
systems, and other features of more
advanced life forms developed. - 438-408 m.y.a.: This was the “Golden Age”
of cephalopods and brachiopods (a clam-like
- 545-505 m.y.a.: reconstruction of Burgess shellfish).
Shale fauna
- The first land plants developed, and the first
ORDOVICIAN PERIOD arthropods (scorpion-like invertebrates)
ventured onto land.
- Few animals and plants began to explore
land; most life was still confined at sea DEVONIAN PERIOD

- Began with shallow, warm seas, but at the - “Age of Fishes”

end experienced a 500,000 year long ice
age, triggered by the drift of Gondwana to - Sea levels were high and global climate was
south polar region warm

- Ended with a mass extinction - Tropics averaged 30C (like the Pacific
today)
- 495 to (Ordovician-Silurian mass extinction)
443 million years ago - Growth rings from corals suggests that there
were more than 365 days then, 404 at the
Fossil Record - Ordovician start then 396 by the end

- 490-443 m.y.a.: Seas held abundant marine - 417 M to (Late Devonian Mass Extinction)
invertebrates with sophisticated adaptations 354 Million years ago
to different conditions.
Fossil Record – Devonian
- Straight-shelled cephalopods, trilobites,
snails, brachiopods, and corals in a shallow - 408-360 m.y.a.: Land plants became
inland sea. common. Vascular plants developed - club
mosses and ferns.
SILURIAN PERIOD
- These plants had structural support from
- Time when reefs grew really big and new stems and limbs and a vascular system
type of ecosystem for marine life providing an internal plumbing system for
water.
- Built by a host of tabulate and rugose corals,
crinoids, and sponges Fossil Record - Late Devonian

- Sea levels role, extensive seas 380-360 m.y.a. - First seed plants - the naked-
seed plants developed. Gymnosperms like
- Bony fish appeared, plants more established Glossopteris developed. Ginkgos are long-lived
in lakes and rivers relics of the ancient family of nakedseed plants,
so are conifers.
- Riverine and wetland habitats
CARBONIFEROUS PERIOD
- (Ordovician-Silurian mass extinction) 443
million years ago to 417 million years ago
- Highest atmospheric oxygen levels, - 286-248 m.y.a.: Amphibians decline;
evolution of first reptiles reptiles and insects increase; first mammal-
like reptiles appear. Nonseed plants decline.
- Plants grew and died and became coal
TRIASSIC PERIOD
- “Coal Measures” coal-bearing rocks
- Began after the worst mass extinction
- Started off warm then dropped and turned to
an ice age that lasted millions of years - Heat, vast, deserts, and warm seas

In north America, it’s divided into two - First mammals and dinosaurs

a. Mississippian - Pangea began to break apart

b. Pennsylvanian - Ended with another mass extinction

- (Late Devonian Mass Extinction) 354 - 247 M to 205 M

Million years ago to 290 Million years ago
Fossil Record - Triassic
Fossil Record – Carboniferous
- 225 m.y.a.: First dinosaurs and mammals;
- 360-286 m.y.a.: Age of amphibians; first explosive radiation of dinosaurs. (Primitive
winged reptiles and first winged insects. Ornithischia, an early dinosaur)
Widespread forests and swamps.
JURASSIC PERIOD
- Ichthyostega had features like a tail that it
inherited from fish; and legs that allowed it - Host to most diverse range of organisms
to move around on land. - First birds and some dinosaurs
Fossil Record Pennsylvanian - Continental break-up = Atlantic Ocean
- 320-290 m.y.a.: peat swamps common, with - Ocean floor is the oldest surviving in the
scale trees, seed ferns, scouring rushes, and planet
large dragonflies
- 205 M to 142 M
PERMIAN PERIOD
Fossil Record – Jurassic
- Started with an ice age and ended with the
most devastating mass extinctions (2) - 213-144 m.y.a.: The Age of dinosaurs;
forests of gymnosperms and ferns cover
- Supercontinent “Pangea”or “entire earth” most of Earth
- Oxygen went from 35% to 15%, today: 21% - 213-144 m.y.a.: Age of dinosaurs
- 290 M to 249 M Fossil Record - Jurassic and Cretaceous
Fossil Record – Permian - 213-65 m.y.a.: Age of dinosaurs. Birds
appear. Fossil Record - Jurassic and
Cretaceous
- Dragonfly, Brazil 7 cm (3 in.) long - The Cretaceous–Paleogene (K–Pg)
boundary, formerly known as the
- 175-65 m.y.a. : This nesting mother, a Cretaceous–Tertiary (K–T) boundary.
birdlike dinosaur called Oviraptor, was
found curled protectively around a nest - K, the first letter of the German word
containing at least 20 eggs - evidence that Kreide (chalk), is the traditional
dinosaurs cared for their young. abbreviation for the Cretaceous Period
and Pg is the abbreviation for the
- Archaeopteryx: an early bird, has skeleton Paleogene Period.
and teeth very similar to those of dinosaurs
as well as detailed impressions of feathers. - the transition between the Cretaceous
and Tertiary periods of geologic time
CRETACEOUS PERIOD characterized by a mass extinction of
many forms of life including the
- Ended with mass extinction of dinosaurs
dinosaurs.
- Warm period with no ice caps; dry land
Fossil Record - K-T Boundary
- Southern England and Midwest USA was
- 65.0 m.y.a.: Cretaceous -Tertiary Boundary
underwater
- Many species and genera, including the
- Sea levels reached the highest
dinosaurs, died out at end of Cretaceous
- Atlantic ocean grew wider, North and South
- One hypothesis: Earth was hit by a meteorite
America drew apart from Europe and
- at Chixulub, in the Yucatan area of Mexico
Africa, India made its way to Asia
PALEOCENE EPOCH
- 142 to 65 M ago
- Dense forest and evolutionary experiments
Fossil Record - Cretaceous
- Mammals and birds evolved
- 144-65 m.y.a.: Plesiosaurs infested the
beaches - India collided with Asia
Fossil Record - Cretaceous and Tertiary - Rise in temperature made climate wetter and
rose sea level
- 144-65 m.y.a. - first flowering plants appear.
After the K-T boundary, flowering plants - 65 m to 54.8 m
diversify and spread explosively over the
planet, as do mammals. Fossil Record - Fossil Record - Tertiary: Paleocene
Cretaceous and Tertiary
- 65-54.9 m.y.a.: Beginning of modern life
- Fossil sweet gum, 1.5 m.y., Idaho - next to forms following the K-T Boundary
modern sweet gum fruit extinctions.

- Age of mammals began, grasslands spread.

Cretaceous- Paleogene (K-Pg) Cretaceous– EOCENE EPOCH

Tertiary (K–T) boundary
- Time of global warming
- Forest thrived and trees in polar regions - 24.6-5.1 m.y.a.: horses, rhinoceri, and
grew elephants.

- Eocene became cooler and drier PLIOCENE EPOCH

- India pushing against Eurasia formed - Looked similar to earth today

Himalayas
- North and South America joined together
- Formation of Alps
- Ice in north pole became permanent,
- Species of grass grassland and tundra thrived

- 54.8 M to 33.7 M - 5.3 to 2.6 million

Fossil Record - Tertiary: Eocene PLEISTOCENE EPOCH

- 54.8-38 m.y.a. - Glaciers came and went, at least 20 cycles

OLIGOCENE EPOCH - Global temp was 5 degrees centigrade cooler

- Start of global cooling - Expansion of deserts

- Glaciers were present - Humans evolved during this epoch

- Grasslands and forests expanded - 2.6 to 11.7 m

- Animals evolved to new, open landscape. Fossil Record - Quaternary: Pleistocene

Prey and predators
- 2.0-0.1 m.y.a.: deer family and elephant
- 33.7 to 23.8 M family

Fossil Record - Tertiary: Oligocene - 2.0-0.01 m.y.a.: horses, cats, elephants,

bison, dire wolves
- 38.0-24.6 m.y.a.: horses, antelopes, cats,
oreodonts - 2.0-0.01 m.y.a.: mammals successfully
colonized all environments
MIOCENE EPOCH
- 2.0-0.01 m.y.a.: subglacial areas,
- Apes arose and diversified
- La Brea tar pits, S. CA
- Ancestors of humans split away with
chimpanzees - < 0.1 m.y.a.: Western Nebraska when first
humans were appearing
- Kelp forests
Timeline: Human Evolution
- 23.8 to 5.3 million
- 55 million years ago (MYA) – First
Fossil Record - Tertiary: Miocene primitive primates evolve
- 24.6-5.1 m.y.a.: horses, antelopes, and other - 8 – 6 MYA – First gorillas evolve. Later,
mammals. chimp and human lineages diverge
- 5.8 MYA – Orrorin tugenensis, oldest found in Israel and dated to 780,000 years
human ancestor thought to have walked on ago
two legs
- 600,000 YA – Homo Heidelbergensislives
- 5.5 MYA – Ardipithecus, early “proto- in Africa and Europe. Similar brain capacity
human” shares traits with chimps and to modern humans
gorillas, and is forest-dwelling
- 500,000 YA – Earliest evidence of purpose-
- 4 MYA – Australopithecines appear. They built shelters – wooden huts – are known
have brains no larger than a chimpanzee’s – from sites near Chichibu, Japan
with a volume around 400 – 500 cm3 -, but
walk upright on two legs. First human - 400,000 YA – Early humans begin to hunt
ancestors to live on the savannah with spears

- 3.2 MYA – Lucy, famous specimen of - 325,000 YA – Oldest surviving early human
Australopithecus afarensis, lives near what footprints are left by three people who
is now Hadar, Ethiopia scrambled down the slopes of a volcano in
Italy
- 2.7 MYA – Paranthropus, lives in woods
and grasslands, has massive jaws for - 280,000 YA – First complex stone blades
chewing on roots and vegetation. Becomes and grinding stones
extinct 1.2 MYA - 230,000 YA – Neanderthals appear and are
- 2.5 MYA – Homo habilis appears. Its face found across Europe, from Britain in the
protrudes less than earlier hominids, but still west to Iran in the east, until they become
retains many ape features. Has a brain extinct with the advent of modern humans
volume of around 600 cm3 – Hominids start 28,000 years ago
to use stone tools regularly, created by - 195,000 YA – Our own species Homo
splitting pebbles – this starts Oldowan sapiens appears on the scene – and shortly
tradition of toolmaking, which last a million after begins to migrate across Asia and
years – Some hominids develop meat-rich Europe. Oldest modern human remains are
diets as scavengers, the extra energy may two skulls found in Ethiopia that date to this
have favoured the evolution of larger brains period. Average human brain volume is
- 2 MYA – Evidence of Homo ergaster, with 1350 cm3
a brain volume of up to 850 cm3, in Africa Fossil Record – Quaternary
- 1.8 – 1.5 MYA – Homo erectusis found in - 4.4-0 m.y.a.: Hominids diverged from an
Asia. First true huntergatherer ancestor, and early ape-like family. (Poor fossil record and
also first to have migrated out of Africa in missing transitional forms complicate the
large numbers. It attains a brain size of story and leave many gaps, but new fossils
around 1000 cm3 are being found each year.)
- 1.6 MYA – Possible first sporadic use of - Ardipithecus ramidus - 4.4 (bipedal, erect
fire suggested by discoloured sediments in forest dweller) Ardipithecus anamensis -
Koobi Fora, Kenya. More convincing 4.2-3.9 (bipedal, apelike skull)
evidence of charred wood and stone tools is
 Australopithecus afarensis (“Lucy”) - 3.9- - Spread of forests
2.8 (bipedal, apelike face with sloping
forehead, human-like bodies. Lived together - Timber and agricultural grew
in family groups.) and other species of - Warm time, but still an ice age
Australopithecus - 3.0-1.1
- Presence of ice caps at the poles
- Homo habilis - 2.2-1.6 m.y.a. (used stone
tools, so may be related to Homo sapiens, - Planet is in an interglacial phase
but skull is like australopithecines)
- 11.7 thousand y.a to present day

Fossil Record Quaternary: Holocene

Upright posture evolved before large brains
- Homo sapiens sapiens 120,000-present
- Upright posture evolved before large brains
Convergent big toe

- Position of inner toe reveals upright posture

- Upright posture evolved before large brains

Convergent big toe

- -Tanzania -ca. 3.5 Ma -damp volcanic ash

Fossil Record – Quaternary

- Hominids (Cont.) Homo erectus - 1.8-0.4

m.y. (Peking man, Java man: developed
large brains, tools, weapons, fire, and
learned to cook food.)

- Homo sapiens archaic - 500-200 t.y.a.

(Skulls intermediate between Homo erectus
and Homo sapiens sapiens)

- Homo sapiens neandertalensis -200-30 t.y.a

(teeth and brain similar to ours, but DNA
different, burial sites suggest they practiced
some form of religion.) Neandertal

HOLOCENE EPOCH

- “Recent”

- Current geological period

- Marked the end of the glacial phase of

recent ice age