The Tree of Life Ch 17.1, 17.2, 17.4

Key Vocabulary Taxonomy- the science of naming and classifying organisms. Taxon- a group of organisms in a classification system. Binomial nomenclature- a standard naming system that gives each species a two-part name using Latin words. Genus-includes one or more physically similar species that are thought to be closely related.

Key Vocabulary Phylogeny- the evolutionary history for a group of species. Cladistics- classification based on common ancestry. Cladogram-an evolutionary tree that proposes how species may be related to each other through common ancestors. Derived Character-trait that differs in structure or function from that found in the ancestral line for a group of species.

Key Vocabulary Bacteria-domain that includes single-celled prokaryotes in the kingdom Bacteria. Archaea- domain that includes prokaryotes that live in extreme environments like deep sea vents, geysers, Antarctic waters, and salt lakes. Classified in kingdom Archaea. Eukarya-domain made up of all eukaryotic cells. Includes kingdoms Protista, Plantae, Fungi, and Animalia.

The Linnaean System of Classification Why do we need a universal name for an organism? What kind of problems would we run into if we didn’t?

The Linnaean System of Classification Before Carol Linnaeaus came up with his classification system, naturalists used to name things on their own. Because there was no universal name it was hard to know what exactly they were talking about. 1750s classification system was born. Taxonomy allows us to group organisms and refer to them so that all scientists know what is being talked about specifically.

The Linnaean System of Classification Linnaean classified the organisms based on physical and structural characteristics. Each organism was put into a group, that was a part of a larger, more general group, until you reached the very beginning and the most broad group of the hierarchy. Each organism gets a two part name. Ex: Homo sapiens. The first part is the genus, the second is the species.

The Linnaean System of Classification Why do we need this naming system? It allows people all over the world to talk about a specific organism without any confusion. Some organisms have several common names.

The Linnaean System of Classification In his system Linnaean has 7 levels, or taxa: Kingdom Phylum Class Order Family Genus Species

The Linnaean System of Classification There are limits to this system. It only classifies based on physical similarities. Remember homologous and analogous structures?

Classification Based on Evolutionary Relationships If you think of yourself as a species, who represents the genus, family, and order?

Classification Based on Evolutionary Relationships Similar traits between species is normally from a common ancestor. Could also be from adapting to a similar environment. Modern classification is based on evolutionary relationships using evidence from living species, the fossil, and molecular data.

Classification Based on Evolutionary Relationships Phylogenies can be represented by tree diagrams that show how different groups of species are related to each other. The most common one we use is a cladogram.

Classification Based on Evolutionary Relationships To figure out evolutionary relationships we use derived characters. We see which derived characters are shared by which species. Closer relations = more derived characters shared.

Classification Based on Evolutionary Relationships Do it yourself: Transportation cladogram: Use bicycle, car, motorcycle, plane, and foot wings Passenger enclosed motor wheels

Classification Based on Evolutionary Relationships Groups of species are placed in order by the derived characters that have added up in their lineage over time. Hash marks are derived characters. Anything above the hash mark share those characters. Nodes are the where the branches come off the main line. They represent the most recent common ancestor. Clades are groups of organisms that share certain traits derived from a common ancestor.

Classification Based on Evolutionary Relationships Now we can classify organisms based on molecular data. Mostly agrees with the physical but sometimes organisms may need to be classified differently. DNA has the last word because any traits that get passed to offspring have to have a genetic basis.

Domains and Kingdoms How do you classify music? By instruments, beat, region, time period?

Domains and Kingdoms With new technology things start to change. Tree of Life is a model that we use that shows the most current understanding of how all living things are related. We started with only 2 kingdoms and over time have increased to 6. 1977 Carl Woese said that all life had to be divided into 3 domains. The domains are above the kingdom level.

Domains and Kingdoms We still use this system today. Three Domains: Bacteria-includes single-celled prokaryotes in the kingdom bacteria. One of the largest groups. Archaea-includes single-celled prokaryotes that have the ability to live in extreme environments. Eukarya-includes all organisms with eukaryotic cells. Includes 4 kingdoms.

Domains and Kingdoms So how can you remember all of the levels in the classification system? Donkey Kong Put Cookies On Fries Get Some Domain, Kingdom, Phylum, Class, Order, Family, Genus, Species put on

Let’s Review Who came up with the original classification system? How were organisms classified? What’s Binomial Nomenclature? What do Cladograms tell us? Who came up with the addition of the Domains? What are the levels of the classification system? Which is the most specific? The most general?