1. Classification: Exploring and Organizing Life’s Diversity

2. History of Classification
Aristotle ( B.C.) developed the “first” system
Based on how an organism looks
Plants and animals
Plants were divided into herbs, shrubs and trees
Animals were divided based on physical characteristics
System was flawed
Bats were considered birds because they had wings
Whales were considered fish because they had fins
Fungi were considered plants
Bacteria and other microorganisms were not included
Didn’t know they existed

3. Carolus Linnaeus Born Carl von Linné (1707-1778)
Developed a system based on physical similarities
Called taxonomy
Developed a system for naming organisms that is still used today
Called binomial nomenclature
2-word naming system using Latin words
The first word is the genus (closely related species)
The second word is the specific epithet.

4. Rules for Scientific Names
1st word is capitalized
2nd word is lowercase
Both words are italicized (if typed) or underlined (if hand-written)
Examples:
Homo sapiens
Canis familiaris
Pinus virginiana
Yersinia pestis

5. What is wrong with these names?
Homo Sapiens
homo sapiens
Homo sapiens

6. Advantages of Binomial Nomenclature
It is universal
The same scientific names are used everywhere on Earth
The scientific name tells you about the organism
Where it is found, what it does, who discovered it, or identifying characteristics
It shows relationships
Organisms of the same genus will have the same first word

7. Taxonomy Science of naming and classifying organisms 8 Levels
Domain
Kingdom
Phylum
Class
Order
Family
Genus
Species
Did King Philip Come Over For Great Spaghetti?
Domain is the least specific (most different organisms grouped)
Species is the most specific (only one type of organism)

9. For Us (Guaranteed Test Question )
Domain: Eukarya
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Primata
Family: Hominidae
Genus: Homo
Species: sapiens
Everyone alive can make perfectly healthy, hearty soup

10. Domains and Kingdoms There are 3 Domains and 6 Kingdoms of life
Bacteria
Archaea
Eukarya
Kingdoms in each domain
Domain: Bacteria
Kingdom: Bacteria
Domain: Archaea
Kingdom: Archaea
Domain: Eukarya
Kingdoms: Protista. Fungi, Plantae, Animalia

11. Cladistics More recent attempt to group Earth’s biodiversity
Groups organisms based on Evolutionary relationships
Separates organisms based on derived characteristics
Much more accurate and insightful
Shows real relationships, not perceived ones
Recently, based more upon DNA than characteristics

12. Cladogram

13. Dichotomous Keys A tool used to identify an organism
Consists of a series of dichotomous statements (2 differing statements)

14. Characteristics of Living Things
In order to be alive, something needs to do all of the following:
Be made up of one or more cells, containing DNA
Obtain and use energy
Grow and develop
Growth=get bigger
Develop=changes throughout life
Reproduce
Respond to the environment
If something lacks even one of these things, it is not living

15. Viruses Viruses are NOT living things
They lack most of the characteristics of living things
They do not grow and develop
They can only reproduce using other organism’s cells
They can not obtain or use energy
They are not made of cells
They do, however, affect living things greatly
Can be pathogenic
Cause disease (cold and flu)
VIRAL DISEASES CANNOT BE TREATED WITH ANTIBIOTICS

16. Prions Prions are infectious proteins (Also not living things)
Found in air, and cause host’s proteins to fold improperly
Causes diseases such as Bovine Spongiform Encephalopathy (Mad Cow Disease) and Creutzfeldt- Jakob Disease (human form)
Causes misshapen proteins in the brain
Brain develops holes and resembles a sponge
Prion diseases are nearly always fatal, as the body has no way to fight them

17. Types of cells There are 2 cell types Prokaryotic Eukaryotic
Lack a nucleus and other organelles
Only organelles they have are ribosomes
Both Domain Bacteria and Domain Archaea
Eukaryotic
Have a nucleus and organelles
Only Domain=Eukarya

18. What are Prokaryotes? Single-celled organisms
Very tiny
Cannot be seen without a microscope
Our microscopes are not powerful enough
Lack a nucleus and most other organelles
Most numerous organisms on Earth
Extremely important organisms.

19. Classification and Evolution
Prokaryotes are split into 2 Domains
Domain Bacteria
Domain Archaea
Everything else on Earth is in Domain Eukarya
Prokaryotes were the first living things to evolve, around 3.8 billion years ago
Only living things on earth until 2 billion years ago
Until 1970s, Archaea were considered to be bacteria (called Archaebacteria)
As more was learned about them, they were given their own domain because they are VERY different from bacteria

20. Domain Bacteria Made up of bacteria Only 1 kingdom-Bacteria
Most abundant living things on Earth.
Live in almost every environment
Air
Ocean
Soil
Intestines
Estimated number of bacteria on earth: 5x1030
You have 10 times more bacterial cells than human cells!

21. Classification of Bacteria
Thousands of bacterial species exist.
Many are classified by shape.
Others are classified based on the color that they stain (Gram staining)

22. Bacterial shapes Baccili: Cocci: Spirilla Rod shaped Sphere-shaped
Spiral-shaped

23. Structure of Bacterial Cells
Bacterial cells are surrounded by a plasma membrane
Most also have cell walls
Surrounding the membranes and cell wall (if present) is a capsule, which further protects the cells
Inside of the bacterial cell is cytoplasm, similar to eukaryotic cells
Floating in the cytoplasm are ribosomes and plasmids (small sections of DNA)
There is no nucleus
Instead, there is a Nucleoid (area with DNA) and may be plasmids (circular DNA) to be exchanged with other bacteria
Bacterial cells also may contain whip-like structures called flagella
Also have hair-like protrusions called pili that allow them to attach to objects

24. Structure of Bacterial Cells

25. How do bacteria get energy?
Some are photosynthetic
Others decompose organic matter
Some can use chemicals from the environment to do a process similar to photosynthesis (called chemosynthesis)
Mutualism
Getting resources from other species, while providing some service to that species (+/+)
Parasitism
Stealing resources from host organisms (+/-)

26. Bacteria and People
You may think that bacteria’s purpose is to make us sick
For some bacteria, this is true
For many others, it is not
Benefits of Bacteria
Create medicine, such as vaccines
Help us digest foods and get vitamins
Decompose wastes
Fix Nitrogen into usable forms for plants
Make foods such as cottage cheese, yogurt, cheese, and many more.

27. Dark side of Bacteria Mycobacterium tuberculosis (Tuberculosis)
Some bacteria can lead to disease
Clostridium tetani
Tetanus aka Lockjaw
Affects muscles (including the heart). Leads to muscle spasms, and can be fatal.
Escherichia coli (E. Coli)
Many strains exist in human intestines in a commensalism relationship. However, some can cause food poisoning.
Transmitted by fecal-oral route. WASH YOUR HANDS AFTER USING THE BATHROOM!!!
Mycobacterium tuberculosis (Tuberculosis)
Second deadliest infectious disease (After HIV/AIDS).
Yersinia pestis
“The Bubonic Plague” or “The Black Death
Killed over 1/3 of the European Population between 1347 and 1353

28. A child and a portrait of a soldier affected with tetanus

30. Spread of the Black Death

31. Controlling Bacteria
Bacteria in food and water can be killed by cooking at a high temperature
Bacteria on surfaces can be killed with cleaning products such as bleach or Lysol
Antibiotics can be used to kill bacteria that are harming humans
Effective against bacterial infections such as strep throat, sinus infections, ear infections, pneumonia, etc.
However, there is a problem

32. Antibiotic Resistance in Bacteria
Some bacterial species are evolving resistance to antibiotics.
The antibiotic kills those that are not resistant, but leaves the one that are resistant
Example: Clostridium difficile
A common bacteria that causes diarrheal disease in hospitals. Hospitals, due to their obsessive cleaning procedures, have selected for resistant strains. Patients are being infected at a high rate, while staying in hospitals.

33. Genetic Diversity in Bacteria
Bacteria reproduce asexually (without sex)
Called binary fission
One bacteria replicates its DNA and then splits
Makes clones-identical copies
Benefit: Quick, little energy used, don’t need a mate
Disadvantage: No genetic diversity
Susceptible to extinction
Conjugation is a way bacteria can increase genetic diversity
Exchanging all or part of a plasmid with another bacteria
No longer identical

35. Domain Archaea Only 1 Kingdom Prokaryotes
Called Archaea
Prokaryotes
First discovered in extreme environments
Originally classified as bacteria
As more was learned about them, they were found to be VERY different from bacteria
Their cell wall is more similar to Eukaryotes than bacteria
They were given their own Domain and Kingdom
Very little is known about these organisms

36. Archaea: Tiny but Tough
Many archaea are extremophiles
Organisms that have evolved to live in extreme conditions.
Example: Hydrothermal vents in the ocean (picture) are very acidic and hot.
Would kill most organisms, yet archaea thrive.
4 types of extremophiles
Halophiles-Survive in very salty water (Dead sea)
Hyperthermophiles- Survive at high heats
Some archaea can survive up to 122° C (252° F)
Acidophiles-Live in highly acidic environments (like near volcanoes)
Alkaliphiles-Live in very basic environments

37. Where else do they live?
Archaea do not only live in extreme environments
They are found nearly everywhere on Earth.
Including in humans (many are found in the human belly button!)
Around 4 % of human microbiome
The microorganisms that live on or in us
They are also important decomposers, and part of Nitrogen cycle
Many archaea also form symbiotic relationships
None are known parasites
Most form mutualistic relationships
Archaea in cattle gut help break down grass and straw, and get nutrients in return

38. Eukaryotes Cells contain a nucleus and other organelles
1 Domain: Eukarya
4 Kingdoms:
Protista
Plantae
Fungi
Animalia

39. Kingdom Protista Not a great classification
Includes any organism that is eukaryotic but is not a plant, animal, or fungus
Not a lot in common, besides being eukaryotic
Some are autotrophic, others are heterotrophic
Some are unicellular, others are multicellular
Some are parasitic, some are producers, some are consumers
Will likely be broken into several kingdoms in the future

40. Kingdom Plantae The plants Mostly autotrophic Most are multicellular
Many contain chloroplasts
Most are multicellular
Contain cell walls

41. Kingdom Fungi Fungi Heterotrophic Have cell walls composed of chitin
Molds, mushrooms, yeast
Heterotrophic
Many are decomposers
Have cell walls composed of chitin
Most are multicellular
A few, such as yeast, are unicellular

42. Kingdom Animalia The animals Multicellular heterotrophs
Lack cell walls
Very diverse
36 phyla
Differentiated based on symmetry, body organization (cells to organ systems), and embryonic development
Vertebrates and invertebrates