1. Classification
To avoid confusion caused by regional names, biologists use a classification system to group organisms in a logical manner and to assign names.
Linnaeus developed the method used to name organisms and group them in a logical manner which gives a universally accepted name.
the scientific name is the universally accepted name given to every species.

2. binomial nomenclature
– the system of naming organisms according to genus and species
Taxonomy is used to classify and assign each organism a universally accepted name.
In taxonomy, each level is called a taxon:
Kingdom
Phylum
Class
Order
Family
Genus
Species

3. Linnaeu’s hierarchial system of classification
Grizzly bear
Black bear
Panda bear
Red fox
Coral snake
Abert squirrel
Sea Star
Animalia
Kingdom
Chordata
Phylum
Mammalia
C;lass
Carnivora
Order
Ursidae
Family
Ursae
Genus
Ursus arctos
Species

4. Modern Evolutionary Classification
Which Similarities Are Most Important?
Early systems of classification grouped organisms together based on visible similarities
appendages
Conical shell

5. Evolutionary Classification
Organisms are grouped into categories that represent lines of evolutionary descent, or phylogeny, not just physical similarities
Phylogeny – evolutionary relationships among organisms

6. Classification Using Cladograms
A cladogram is a diagram that shows evolutionary relationships among organisms based on shared derived characters.

7. Similarities in DNA and RNA
African vulture
Marabou stork
American vulture
The American vulture and the Marabou stork are more closely related than the American vulture and the African vulture
Similarities at the DNA level in the genes of organisms can be used to help determine classification

8. Molecular Clocks
By comparing the DNA sequences of two or more species, biologists estimate how long the species have been separated

9. three-domain system
The three-domain system was first invented in 1990, but not generally accepted until later.
One main characteristic of the three-domain method is the separation of Archaea and Bacteria
previously grouped into the single kingdom Bacteria (also called Monera).
Streptococcus bacteria can live in a persons body and cause illnesses like strep throat
Archaea are the most ancient organisms on Earth and they exist in extreme environments

10. three-domain system
The majority of biologists accept the domain system, but a large minority use the five-kingdom method.

11. Extremophiles
Extremophilic microbes can be found thriving in some of the most hostile environments imaginable —
swimming in near-boiling water
eating rocks
in subzero temperatures
where radiation levels rival nuclear reactors

12. What is an Extremophile?
An extremophile is an organism that thrives under "extreme" conditions.
The term frequently refers to prokaryotes and is sometimes used interchangeably with Archaea. extremophiles come in all shapes and sizes
our understanding of the diversity of extreme habitats increases daily.

13. Terms Used to Describe Extremophiles
They are a combination of the suffix –phile, meaning "lover of," and a prefix specific to their environment. For example, acidophiles are organisms that love (phile) acid (acido).
Acidophile: An organism that grows best at acidic (low) pH values.
Alkaliphile: An organism that grows best at high pH values.
Anaerobe: An organism that can grow in the absence of oxygen.

14. Review
In biology, binomial nomenclature is the formal system of naming specific species.
Each species name is in (modern scientific) Latin and has two parts, so that it is popularly known as the “scientific name " of the species.
The species is the lowest level in the system for classifying organisms.

15. Genus and species
As the words "binomial", "binominal" and "binary" the scientific name of each species is formed by the combination of two words
the genus name (also called the generic name).
a second word identifying the species within that genus, (also called the specific epithat)

16. Genus and species
Species names are usually in italics; for example, Homo sapiens. When handwritten, they should be underlined; for example, Homo sapiens. Each name should be underlined individually.
The genus name is always written with an initial capital letter.
For example, the entire tiger species is Panthera tigris

17. Cladistics
Cladistics is the hierarchical classification of species based on evolutionary ancestry.
Cladistics is distinguished from other taxonomic systems because it focuses on evolution rather than similarities between species
Cladistics generates diagrams called cladograms that represent the evolutionary tree of life.
DNA and RNA sequencing data are used in cladistics.
The word cladistics is derived from the ancient Greek meaning "branch."

18. Kingdom Protista