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Needham
• It was known at the time that heat was lethal to living
organisms.
• Needham theorized that if he took chicken broth and
heated it, all living things in it would die.
• After heating some broth, he let a flask cool and sit at a
constant temperature.
• Result: Lots of microorganisms grew in flask
Experiment
• Took Needham’s testing further and sealed
some of the jars so no air could enter
• Boiled meat broth in two flasks
• Open flask vs. sealed flask
• Result: After three days, the broth in the open
flask was cloudy = microorganism growth
Pasteur’s Experiment
• He repeated Spallanzani’s experiment, using a
curved neck flask
• Left it open for one year
• Result: broth remained clear
• Broke the neck & left it for one day - it was
cloudy
• Conclusion to all 3 experiments:
spontaneous generation
disproved
• The New hypothesis:
biogenesis: all living things
come
from other living things.
Scientists
Hypothesis
Redi
Maggots developed
from eggs of flies
Draw the
Experiment
Results
Conclusion
The uncovered
jar had maggots
& the covered
one didn’t
Spontaneous
generation does not
occur
Needham
Microorganisms
were produced
spontaneously
Spontaneous
Microorganisms generation occurs in
microorganisms
grew
Spallazani
Microorganisms
are produced by
other
microorgansisms
Spontaneous
No
microorganisms generation does not
occur.
grew
Pasteur
Microorganisms
are produced by
other
microorgansisms
No microorganisms Spontaneous
generation does
grew
not occur.
Evolution
Review
DESCENT WITH MODIFICATION
(GENETIC CHANGE OVER TIME)
Evolution http://glencoe.mcgraw-hill.com/sites/9834092339/student_view0/chapter20/animation__mechanisms_of_evolution.html
Cyanobacteria is a phylum of bacteria that obtain their energy
through photosynthesis. The name "cyanobacteria" comes from the
color of the bacteria (Greek: = blue). Although often called bluegreen algae, that name is a misnomer as cyanobacteria are
prokaryotic and algae are eukaryotic.
By producing oxygen as a gas as a by-product of photosynthesis,
cyanobacteria are thought to have converted the early reducing
atmosphere into an oxidizing one, which dramatically changed the
composition of life forms on Earth by stimulating biodiversity and
leading to the near-extinction of oxygen-intolerant organisms.
According to endosymbiotic theory, the chloroplasts found in plants
and eukaryotic algae evolved from cyanobacterial ancestors via
endosymbiosis.
Archaebacteria Sub-kingdom of the kingdom Prokaryote,
which, on the basis of both RNA and DNA composition
and biochemistry, differs significantly from other bacteria.
They are thought to resemble ancient bacteria that first
arose in extreme environments such as sulphur-rich,
deep-sea vents.0.
TYPES OF ADAPTATIONS
• Structural
• Behavioral
• Physiological
Let’s look at each type as we consider 2
species: the tundra & icecap-dwelling arctic
fox & the desert dwelling fennec fox.
arctic fox (Alopex lagopus)
fennec fox (Vulpes zerda)
Structural Adaptation: The form that the organism
takes.
EX: Big ears and small ears of foxes.
Heat escapes easily from the blood that passes through the vessels
in the fennec fox’s ears. Cool blood from the ears then circulates
through the body & keeps the fennec fox from overheating.
Structural Adaptations in Plants
Behavioral Adaptation: These are
innate (inherited) actions that
individuals of the species perform.
• Arctic fox:
– Can be active any time of the day; ready to
find food whenever available.
• Fennec fox:
– Is nocturnal; sleeps during the day & hunts
at night
Physiological Adaptation: Related to
the biochemical processes at work
within an organism’s body.
• Compare the processing of food & water:
– Arctic fox: food is scarce in winter;
effective at storing food energy as fat.
– Fennec fox: little free water available;
adapted to get all moisture it needs from
fruit, roots, & leaves.
A whole lot happens inside our bodies and inside other
organisms. Sometimes it is hard to see the physiological
adaptations that an organism has. Organisms that make
venom or poison are good examples of physiological
adaptations. Or animals and plants in the desert that have
special tissues to hold or absorb water are also good
examples.
The Giant African
Millipede is toxic. It
makes a poison that it
releases through its
skin, it keeps it from
being a tasty treat for
predators
Snakes make venom to
protect themselves and
capture prey. It is a great
adaptation
Plants are able to bend
toward the light, a process
called phototropism. This is
an excellent example of a
physiological adaptation
because it occurs inside the
plant as a result of chemical
reaction
The Rate of Evolution
Different kinds of organisms evolve at different rates
Bacteria evolve much faster than complex cells
The rate of evolution also differs within the same
group of species
In punctuated equilibrium, evolution occurs in spurts
In gradualism, evolution occurs in a gradual, uniform
way
Punctuated equilibrium
Gradualism
PATTERNS OF EVOLUTION
Coevolution: Change of two or more species in
close association with each other.
EXAMPLE: Bumblebees and
the flowers they pollinate
have co-evolved so that
both have become
dependent on each other
for survival.
Convergent Evolution: organisms that
are very similar but are not closely
related. This happens because of a
change within the environment.
Analogous structures are the
result of convergent evolution.
DIVERGENT EVOLUTION:Two or
more related species that become more
dissimilar due to different
environments.
•This usually produces another species
EXAMPLE:
GALAPAGOS
FINCHES
EVOLUTIONARY FORCES






Five evolutionary forces can significantly
alter the allele frequencies of a population
1.
2.
3.
4.
5.
Mutation
Migration
Genetic drift
Nonrandom mating
Selection
Mutation



The ultimate source
of new variation
Errors in DNA
replication and
change in DNA due to
extraneous factors
Mutation rates are
too low to
significantly alter
allele frequencies on
their own
Migration

Movement of individuals from one population to
another

Immigration: movement into a population

Emigration: movement out of a population
A very
potent
agent of
change
Genetic Drift






Random loss of alleles
More likely to occur in
smaller population
Founder effect
Small group of individuals
establishes a population in a
new location
Bottleneck effect
A sudden decrease in
population size due to
natural forces


Mating that occurs
more or less frequently
than expected by
chance
Inbreeding

Mating with relatives or self
Increases homozygosity

Outbreeding



Mating with non-relatives
Increases heterozygosity
Nonrandom Mating
Selection





Some individuals leave
behind more offspring
than others
Artificial selection
Breeder selects for desired
characteristics
Natural selection
Environment selects for
adapted characteristics
CLASSIFICATION
• HISTORY OF TAXONOMY
–Taxonomy the branch of
biology that groups and
names organisms based on
their different characteristics
• Organisms are named using Latin,and in a way
that no two have the same name
•
ex) Canis lupis
Common names make poor labels
Zea saccharata
Corn
Zea mays indurata
Ursus arctos horribilis
Bears
Phascolarctos cinereus
Robins
ARISTOTLE – GREEK
PHILOSOPHER
•1ST TO CLASSIFY ORGANISMS
MORE THAN 2,000 YEARS AGO.
•HE CLASSIFIED ALL LIVING
THINGS AS EITHER PLANT OR
ANIMAL
•HE GROUPED PLANTS BASED ON THEIR STEMS
•HE GROUPED THE ANIMALS BASED ON WHERE
THEY LIVED OR DWELL.
THE ANIMALS WERE DIVIDED
INTO 3 CATEGORIES:
ANIMALS
LAND
AIR
WATER
• The classification system of the Middle Ages was
known as the polynomial system
– Polynomials were a string of Latin words or
phrases consisting of up to 12 or more words
– This system was difficult and confusing
– Even worse names were often changed often
and without notice
•In the 1750s, the
Swedish biologist
Carolus Linnaeus
developed the
binomial system
– Binomials are twopart names
•They have become
our standard way
of designating
species
Binomial nomenclature: two-word naming system
(scientific name) for different species
Scientists all over the world can communicate about an
organism using its scientific name, regardless of country,
language, etc.
Written in Latin because Latin is no longer used and therefore
does not change
Each scientific name has two words that are italicized or
underlined
oFirst word: genus name (capitalized)
oSecond word: species name (not capitalized)

Homo sapiens
Genus Species
36
Linnaean System
• Taxonomist use a classification system to classify
organisms
• Carolus Linnaeus (1707-1778)
• Classified organisms based on their morphology
(form & structure)
• Binomial nomenclature system: two-part naming
• Linnaeus is the “father of classification”
• The system of classification is used by taxonomists.
Binomial Nomenclature
• It gives every species a two-part scientific name. For
example, a ladybug found in the United States goes by
the fancy name of Harmonia axyridis.
• The first part of a scientific name, like Harmonia, is
called the genus. A genus is typically the name for a
small group of closely related organisms. The second part
of a scientific name, axyridis in this example, is the
specific epithet. It is used to identify a particular species
as separate from others belonging to the same genus.
Together, the genus plus the specific epithet is the full
scientific name for an organism.
10
38
• Binomial Nomenclature Rules
• Because scientific names are unique species identifiers,
they ensure that there is never any confusion as to which
organism a scientist may be referring. Additionally, there
are some important rules that must be followed to keep
all binomial names standardized:
1. The entire two-part name must be written in italics (or
underlined when handwritten).
2. The genus name is always written first.
3. The genus name must be capitalized.
4. The specific epithet is never capitalized.
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•EX: lion
– -PANTHERA
LEO
–Would be written:
–Panthera leo
–If writing by hand:
–Panthera leo
HOW MANY SPECIES
ARE THERE?
•Since the time of Linnaeus, about 1.5
million species have been named
•However, scientists estimate that at
least 10 million species exist
–At least two-thirds of these occur in
the tropics
PHYLOGENY
• Taxonomy also enables us to glimpse at the
evolutionary history of life on earth
• The evolutionary history of an organism and its
relationship to other species is called phylogeny
• The reconstruction and study of phylogenetic
trees is called systematics
– Phylogenetic tree= a family tree that shows
the evolutionary relationships thought to
exist among groups of organisms.
Phylogenetic trees are generally derived from
several lines of evidence such as: morphological,
embryological, & macromolecular similarities
A relatively new system of phylogenetic
classification is called cladistics.
As groups of organisms diverge and evolve from
a common ancestor, they keep some of the same
traits (derived traits)
oCladogram: branching diagram that shows
the derived traits of a group of organisms
(like a pedigree that shows evolution)
oThe closer 2 organisms are in a cladogram, the
more probable that they are closely related by
evolution
o
EX: if the group being considered is birds, one example of a derived character
is feathers. Most animals do not have feathers; birds are the only animals that
do, therefore it is safe to assume that feathers evolved within the bird group.
Shared derived characters, particularly a group of several
shared derived characters, are strong evidence of common
ancestry between organisms that share them.
When we do studies in comparative anatomy, and find that
different numbers of shared derived characters exist between
different groups, we can draw a diagram of branching lines which
connect those groups, showing their different degrees of
relationship.
Diagrams showing the relationships of
various organisms and their derived traits
look like a slanted football field and are
called cladograms.
http://www.youtube.com/watch?v=46L_2RI1k3k
http://ccl.northwestern.edu/simevolution/obonu/cladograms/Open-This-File.swf
Cladogram practice handout
Father of
Classification
Carl Linnaeus
Binomial Nomenclature
• Universal naming system still used today
• Two-part: Genus and Epithet (description of
species)
• Genus IS capitalized; epithet is NOT
• Both names are italicized or underlined
• Ex. Felix domesticus (genus, species)
•
-or• Ex. Homo sapiens
Higher Categories
• Scientists use a hierarchical system to classify
organisms (high low)
• Higher categories = more general
• Lower categories = more specific
• 7 levels of classification
• 8th = domain
TAXONOMY CATEGORIES
Taxonomists use a hierarchical system to
classify organisms comprised of 7 different
levels of organization •Kingdom
As you go
down the
category gets
more
specific.
•Phylum
•Class
•Order
•Family
•Genus
•Species
Linnaeus was
responsible for
this system!
•The designation of kingdoms has
changed over the years
–Originally there were only two kingdoms
•As more information about organisms
was obtained, the number of kingdoms
increased.
•A taxonomic level higher than kingdom
has been recognized- Domain.
53
Linnaean System of Classification
Domain
Kingdom
Phylum
Class
Order
Family
Genus
Species
Current
Levels of
Organization
https://www.brainpop.com/science/diversityoflife/classification/
D, K, P, C, O, F, G, S
•
•
•
•
•
•
•
•
The Current Categories
Do
Keep
Penguins
Cold
On
Frozen
Ground
Sometime
s
“Did King Philip
Come Over For
Garlic Spaghetti”
“Do Kings Play Chess
On Fine Grained
Sand”
Now create your
Some other sentences:
own… the crazier it is
•Do Kids Prefer Cheese Over Fried Green Spinach.
the better you will
•Do Koalas Prefer Chocolate Or Fruit, Generally Speaking
remember!
•Do Keep Precious Creatures Organized For Grumpy Scientists
All 8 names for US!! (humans)
The 3 DOMAINS
DOMAIN ARCHAEA
•Consists of only one
kingdomArchaebacteria
–Archaebacteria inhabit
some of the most
extreme environments
on earth
–They share certain key
characteristics
•Cell walls lacking
peptidoglycan
•Unusual lipids and
unique rRNA sequences
ARCHA
EA
•Live in harsh
environments
•Example: sewage
treatments plants &
thermal vents, etc.
•May represent the
1st cells to have
evolved
DOMAIN BACTERIA
• Consists of only one kingdom- Eubacteria
–Bacteria are the most abundant organisms on
Earth
•There are more bacteria living in your mouth right
They
play
critical
roles
now
than
there are
mammals on Earth
throughout the biosphere
Most taxonomists recognize 1215 major groups
–Bacteria are as different from
archaebacteria as they are from
eukaryotes
BACTERIA
• Some cause human
diseases
• Bacteria are
present in all
habitats on
earth.
•Example: in the
intestines of
animals
EUKARYA
• Divided into kingdoms…
Appeared about 1.5 billion years ago
Consists of four kingdoms
1. Animalia (animals)
2. Plantae (Plants)
3. Fungi (Mushrooms, yeast)
4. Protista (algae)
63
Six-Kingdom System
• Carl Woese
• A kingdom is the largest and most
broad level of classification
Animalia
▪ Plantae
▪ Fungi
▪ Protista
▪ Archaeabacteria
▪ Eubacteria
▪
Descriptions of Kingdoms
• Animalia: Eukaryotic,multicellular,
heterotrophic.
•
EX: wolves
• Plantae: Eukaryotic, multicellular and
autotrophic.
•
EX: Rose
• Fungi: Eukaryotic, uni/multicellular,
heterotrophic
•
EX: mushrooms, molds, yeasts
Descriptions CONT….
• Protista: Eukaryotic, uni/multi, both auto and
heterotrophic, usually found in a water
environment
•
EX: algae, amoeba
• Archaeabacteria: Prokaryotic, unicellular,
auto/heterotrophic and lives in harsh
environments.
•
EX: methanogens, thermophiles
• Eubacteria: same as archaebacteria except
living conditions are favorable bacteria
•
EX: food poisoning, tooth decay
Building Family Trees
• Phylogeny - Evolutionary
history of an organism and
its relationship to other
species
• Cladogram- Evolutionary
lineage based on
PHENOTYPES
• Phylogenetic trees Evolutionary lineage based
on GENOTYPES
DICHOTOMOUS KEYS
•A written aide in the classification
of organisms
•Uses pairs of contrasting,
descriptive statements to lead to
the identification of an organism.
Dichotomous
Key Sample
Key:
1. Has light blue colored body… go to 2
Has dark blue colored body… go to 4
2. Has 4 legs… go to 3
Has 8 legs… Deerus octagis
3. Has a tail… Deerus pestis C
Does not have a tail… Deerus
B magnus
4. Has a pointy hump… Deerus humpis
A
Does not have a pointy hump… go to
F5
5. Has ears… Deerus darkus
Does not have ears… Deerus deafus
D
E