Needham It was known at the time that heat was lethal to living organisms. - PowerPoint Presentation

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NeedhamIt 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

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Spallanzani’s Experiment

Took Needham’s testing further and sealed some of the jars so no air could enterBoiled meat broth in two flasksOpen flask vs. sealed flaskResult: After three days, the broth in the open flask was cloudy = microorganism growth

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Pasteur’s Experiment

He repeated Spallanzani’s experiment, using a curved neck flaskLeft it open for one year Result: broth remained clearBroke the neck & left it for one day - it was cloudy

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Conclusion to all 3 experiments:

spontaneous generation disproved

The New hypothesis:

biogenesis:

all living things come

from other living things

.

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ScientistsHypothesisDraw the ExperimentResultsConclusionRediNeedham SpallazaniPasteur

Maggots developed from eggs of flies

The uncovered jar had maggots & the covered one didn’t

Spontaneous generation does not occur

Microorganisms were produced spontaneously

Microorganisms grew

Spontaneous generation does not occur.

Microorganisms are produced by other microorgansisms

No microorganisms grew

Spontaneous generation does not occur.

Spontaneous generation occurs in microorganisms

Microorganisms are produced by other microorgansisms

No microorganisms grew

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EvolutionReview

(GENETIC CHANGE OVER TIME)

DESCENT WITH MODIFICATION

Evolution

http://glencoe.mcgraw-hill.com/sites/9834092339/student_view0/chapter20/animation_-_mechanisms_of_evolution.html

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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 blue-green 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.

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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.

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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.

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Structural Adaptations in Plants

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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

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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.

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 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.

Snakes make venom to protect themselves and capture prey. It is a great adaptation

      

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

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

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Different kinds of organisms evolve at different ratesBacteria evolve much faster than complex cellsThe rate of evolution also differs within the same group of speciesIn punctuated equilibrium, evolution occurs in spurtsIn gradualism, evolution occurs in a gradual, uniform way

The Rate of Evolution

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Punctuated equilibrium

Gradualism

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PATTERNS OF EVOLUTIONCoevolution: 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.

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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.

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DIVERGENT EVOLUTION:Two or more related species that become more dissimilar due to different environments. This usually produces another species

EXAMPLE:

GALAPAGOS FINCHES

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Five evolutionary forces can significantly alter the allele frequencies of a population1. Mutation2. Migration3. Genetic drift4. Nonrandom mating5. Selection

EVOLUTIONARY FORCES

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The ultimate source of new variation Errors in DNA replication and change in DNA due to extraneous factorsMutation rates are too low to significantly alter allele frequencies on their own

Mutation

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Movement of individuals from one population to another

Immigration: movement into a populationEmigration: movement out of a population

Migration

A very potent agent of change

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Random loss of allelesMore likely to occur in smaller populationFounder effectSmall group of individuals establishes a population in a new location

Bottleneck effectA sudden decrease in population size due to natural forces

Genetic Drift

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Mating that occurs more or less frequently than expected by chanceInbreeding Mating with relatives or selfIncreases homozygosity

OutbreedingMating with non-relativesIncreases heterozygosity

Nonrandom Mating

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Some individuals leave behind more offspring than othersArtificial selection Breeder selects for desired characteristicsNatural selectionEnvironment selects for adapted characteristics

Selection

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HISTORY OF TAXONOMY

CLASSIFICATION

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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

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Corn

Bears

Robins

Common names make poor labels

Zea saccharata

Zea mays indurata

Ursus arctos horribilis

Phascolarctos cinereus

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ARISTOTLE – GREEK PHILOSOPHER1ST 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.

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THE ANIMALS WERE DIVIDED INTO 3 CATEGORIES:

ANIMALS

LAND

AIR

WATER

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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

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In the 1750s, the Swedish biologist Carolus Linnaeus developed the binomial systemBinomials are two-part namesThey have become our standard way of designating species

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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 changeEach scientific name has two words that are italicized or underlinedFirst word: genus name (capitalized)Second word: species name (not capitalized)Homo sapiensGenus Species

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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.

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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

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Binomial Nomenclature RulesBecause 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:The entire two-part name must be written in italics (or underlined when handwritten).The genus name is always written first.The genus name must be capitalized.The specific epithet is never capitalized.

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EX: lion

-PANTHERA LEO Would be written:Panthera leoIf writing by hand:Panthera leo

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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

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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.

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Phylogenetic trees

are generally derived from several lines of evidence such as: morphological, embryological, & macromolecular similarities

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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)Cladogram: branching diagram that shows the derived traits of a group of organisms (like a pedigree that shows evolution)The closer 2 organisms are in a cladogram, the more probable that they are closely related by evolution

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.

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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

.

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Cladogram practice handout

http://ccl.northwestern.edu/simevolution/obonu/cladograms/Open-This-File.swf

http://www.youtube.com/watch?v=46L_2RI1k3k

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Carl Linnaeus

Father of Classification

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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

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Higher Categories

Scientists use a hierarchical system to classify organisms (

high



low

)

Higher categories = more general

Lower categories = more specific

7

levels of classification

8

th

= domain

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Taxonomists use a hierarchical system to classify organisms comprised of 7 different levels of organization

TAXONOMY CATEGORIES

KingdomPhylumClassOrderFamilyGenus Species

As you go down the category gets more specific.

Linnaeus was responsible for this system!

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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

.

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Linnaean System of Classification

Domain KingdomPhylumClassOrder Family Genus Species

Current Levels of Organization

https://www.brainpop.com/science/diversityoflife/classification/

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The Current Categories

D

o

KeepPenguinsCold OnFrozenGround Sometimes

Now create your own… the crazier it is the better you will remember!

“

Did King Philip Come Over For Garlic Spaghetti”“Do Kings Play Chess On Fine Grained Sand”

D,  K, P, C, O, F, G, S

Some other sentences:

Do Kids Prefer Cheese Over Fried Green Spinach.

Do Koalas Prefer Chocolate Or Fruit, Generally Speaking

Do Keep Precious Creatures Organized For Grumpy Scientists

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All 8 names for US!! (humans)

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The

3

DOMAINS

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DOMAIN ARCHAEA

Consists of only one kingdom- ArchaebacteriaArchaebacteria inhabit some of the most extreme environments on earthThey share certain key characteristicsCell walls lacking peptidoglycan Unusual lipids and unique rRNA sequences

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ARCHAEA

Live in harsh environmentsExample: sewage treatments plants & thermal vents, etc.May represent the 1st cells to have evolved

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DOMAIN BACTERIA

Consists of only one kingdom- EubacteriaBacteria are the most abundant organisms on EarthThere are more bacteria living in your mouth right now than there are mammals on Earth

They play critical roles throughout the biosphere

Most taxonomists recognize 12-15 major groups

Bacteria are as different from archaebacteria as they are from eukaryotes

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BACTERIA

Some cause human diseases

Bacteria are present in

all

habitats on earth.

Example: in the intestines of animals

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EUKARYA

Divided into kingdoms…

Appeared about 1.5 billion years ago

Consists of

four

kingdoms

Animalia (animals)

Plantae (Plants)

Fungi (Mushrooms, yeast)

Protista (algae)

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Six-Kingdom System

Carl Woese

A kingdom is the

largest

and most broad level of classification

Animalia

Plantae

Fungi

Protista

Archaeabacteria

Eubacteria

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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

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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

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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

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DICHOTOMOUS KEYS

A written aide in the classification of organismsUses pairs of contrasting, descriptive statements to lead to the identification of an organism.

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Key:1. Has light blue colored body… go to 2 Has dark blue colored body… go to 42. Has 4 legs… go to 3 Has 8 legs… Deerus octagis3. Has a tail… Deerus pestis Does not have a tail… Deerus magnus4. Has a pointy hump… Deerus humpis Does not have a pointy hump… go to 55. Has ears… Deerus darkus Does not have ears… Deerus deafus

B

A

C

F

D

E

Dichotomous Key Sample

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