Honors Biology Unit 12 Notes – Classification of Life

What is the modern classification system?

Domain, Kingdom, Phylum, Class, Order, Family, Genus, Species

Binomial nomenclature

 each type of organism is given a unique, 2-word, latin scientific name showing the genus and species of the organism.  Genus is capitalized.

Phylogeny

 the evolutionary history of a species; often classification of organisms is based on their phylogeny

Phylogenetic Tree

- a diagram that illustrates the evolutionary relationship between groups of organisms based on characteristics such as:

- biochemical similarities

- embryological development

- fossil record

Cladogram

 a diagram that illustrates the evolutionary relationship between groups of organisms based on shared derived traits.

Shared derived traits

- traits that organisms have acquired from their ancestors and share with other members of the group

Clade

 a group of species that share certain specific traits that were derived from their ancestors

Dichotomous Key

- a reference tool that uses a series of paired choices to progressively lead to the identification of an unknown organism

 Viruses

- tiny, non-living biological particles; not a cell!

- have genetic material but lack a nucleus/organelles/cell membrane

- much smaller than even bacteria

- disease-causing pathogens

- must invade other cells in order to replicate themselves

Vaccines

- discovered in 1796 (Edward Jenner)

- used to prepare the immune system for a viral attack

Virus Characteristics of Life

• no growth

• no metabolism

• no homeostasis

• mutations

• genetic code is DNA or RNA

• reproduction only within host cells

Cell characteristics of life

• growth

• homeostasis

• metabolism

• mutation

• DNA genetic code

• reproduction independently