Classification

The evolution of Complexity:single cell prokaryote to multicellular

eukaryotes

Aristotle to Linneaus

Taxonomy- classifying organismsBinomial nomenclature and scientific namesCanis lupus, Turdis migratoris, Felis catusSystematics- the study of biodiversity and its

classification, create phylogeniesPhylogeny- an organism’s evolutionary history, a

phylogenetic tree

Modern Classification System• Domain Archea, Eubacteria, and

Eukarya• Kingdom Archeabacteria, Eubacteria,

Protista, Fungi, Plant, Animal• Phylum • Class • Order• Family• Genus First part of Scientific name• Species Second part of Scientific name

The Evolution of Complexity

• Earth is approximately 4.5 billion years old• 1st living things, prokaryotic bacteria cells are

found in the fossil record dating 3.5 billion years ago

• 1st eukaryotic cells appear in fossil record dating 2.1 billion years ago

• Between 635-530 million years ago the fossil record shows the diversity of algae and small animal like organisms

Origin of Life• Spontaneous Generation: life from non-life

was replaced with – Biogenesis• Oparin’s hypothesis of the origin of life was

tested by Miller and Urey, creating organic compounds but not life

• Endosymbiosis- the hypothesis behind the evolution of eukaryotes from prokaryotes

• What is a Virus?- nonliving…

Composed of genetic material, RNA or DNA, and a protein coat

Genetic material surrounded by a protein coat, must have a host cell in order to reproduce

Life cycles: Lytic (kills host cell) or Lysogenic (incorporates DNA into host)

Human viral diseases

Virus- disease• Flavivirus- Yellow Fever• HIV- AIDS• Herpes virus 3- Chicken pox• Filovirus- Ebola• Hepatitus B- Hepatitus• Influenza virus- Influenza or

pneumonia• Epstien- Barr virus- Mono

• Polio virus- Polio• Rhabdovirus- Rabies• Voriola virus- Smallpox• Paramyxovirus- Mumps

3 Domains

1. Archea2. Eubacteria3. Eukarya

Bacteria once belonged to the same Kingdom, Monera, but through Molecular Biology and the study of evolution, Biologist realized they had critical differences and should be placed into their own category so the “Domain” classification level was created.

6 Kingdoms

Archea and Eubacteria• Archea Kingdom

All prokaryotic single celled organisms. No Peptidoglycan in cell wall Most ancient and extremeThey live in the harshest environmentsMethanogens (anaerobic), thermoacidophiles

(hot) and halophiles (salty)• Eubacteria Kingdom

True bacteria, all prokaryotic single celledHave Peptidoglycan in cell wallClassified by their shape and gram staining

Gram + have more peptidoglycan and stain purpleGram – have less peptidoglycan and stain pink

Shapes and Examples

• Sphere- Cocci, can occur in chains Streptococcus Pneumoniae which can cause strep throat or Scarlet fever, or grapelike clusters Staphylococcus aureus which can cause skin infections and Toxic Shock syndrome

• Rod- Bacillus ex Escherichia coli (E.coli), Lactobacilli which can cause tooth decay or one strain makes Sourdough bread, other bacilli can cause botulism, typhoid fever, and anthrax

• Spiral- Spirilla comes in 3 shapes 1. Vibro which is curved caused Cholera, 2. Spirillum (thick spiral), and 3. Spirochete (thin spiral) ex. Treponema pallidum causes Syphilis and another strain can cause Lyme disease

Essential Bacteria: ecosystems depend on these small organisms

• Cyanobacteria- photosynthetic/producers, building blocks of most aquatic food webs

• Nitrogen- Fixing Bacteria- symbiotic relationship with plants, they help them absorb nitrogen from the soil.

• Helpful: fermentation, digestion, biotechnology, nitrogen fixing, decomposers, oxygen producers

• Antibiotics kill bacteria by destroying the cell wall, gram negative have an extra lipid layer that prevents the antibiotics from entering the cell.

Reproduction• Bacteria reproduce asexually, binary fission• Each bacteria has a single chromosome but can have

additional DNA in the form of plasmids.• Plasmids increase Bacterial genetic variation and

contribute to Bacteria evolution• Plasmids can be exchanged between different bacteria

(even different species) by a process called conjugation.• Plasmids can also be taken up by bacteria from their

environment via transformation.• Additional DNA recombination can be introduced via a

bacteriophage, this is called transduction.

Review of BacteriaAll bacteria:• Reproduce asexually• Single celled• Have cell wall• Single strand of DNA

Some Bacteria:• Autotrophic • Heterotrophic• Some move by flagella,

slime, spiral motion• Some produce endospores

which allow them to go dormant during hostile conditions

• Some produce toxins