Classifying the Diversity of Life– Systematics: Study of the diversification of living

forms, both past and present, and their relationships

– Taxonomy: The academic discipline of defining groups of biological organisms on the basis of shared characteristics

Some Basics of Taxonomy– Carolus Linnaeus: A Swedish botanist, physician, and

zoologist who is know as the father of taxonomy. He traveled through Sweden classifying types of plants and animals

Naming Species– Linnaeus’s system gives a species a two part latinized name or a binomial– First part of binomial is the genus– Second part refers to the particular species inside the genus– The first letter is capitalized and the whole binomial is italicized– Humans scientific name is Homo sapiens

Hierarchical ClassificationDomain:BacteriaArchaeaEukaryota

Kingdom:AnimaliaPlantaeFungiProtistaArchaeaBacteria

Domain Highest/ largest classification

Eukarya

Kingdom Kingdom is put into Domain

Animalia

Phylum Phylum is put into kingdom

Chordata

Class Class is put into phylum

Mammalia

Order Order is put into class

Carnivora

Family Family is put into order

Felidae

Genus Genus is put into family

Felis

Species Name of species Felis catus

Figure 14.21

As you go higher up on the chart, the species gets more specific

Human Classification:

Eukaryote

Classification and Phylogeny– Phylogeny: the evolutionary history of a species

– How an organism is named and classified reflects its place on the evolutionary tree– As species are put into groups, the product takes on the pattern of a phylogenetic tree

Figure 14.22

To make phylogenetic trees and classify organisms, we homologous similarities

Phylogenetic tree: shows the evolutionary relationship among species

The classification is reflected in the finer branching of the phylogenetic tree

Sorting Homology from Analogy- Homologous Structure: May look and function differently, but

exhibit fundamental similarities because they evolved from the same structure, that existed in the common ancestor (whale limbs swim, wings fly, but look similar)

• one of the best sources of information about phylogenetic relationships;

– Convergent evolution: Species from different evolutionary branches can have structures that are similar is natural selection has shaped analogous adaptations

– Analogy: The similarities of structure between two species that are not closely related

Molecular Biology as a Tool in Systematics

– Molecular systematics

-The more recently 2 species have branched from a common ancestor, the more similar their DNA and amino acid sequences are. -Molecular systematics provides a new way to test the diversity of species

~Uses computers to analyze and test evolutionary relationships of 2 species

Figure 14.23

-some fossils are preserved in such a way that you can extract DNA for comparison with modern organisms

The Cladistic Revolution– Cladistics: A scientific search for clades or specific branches on the tree of life, with ancestrial species and

all their descendants. This search involves finding homologies, which connect species into smaller groups.

Figure 14.24

-This is an example of cladistics. -In the picture the 3 mammals are compared to the turtle. -The primitive and derived characters are seperated, with the primitive characters being those contained by all animals because of common ancestry and derived characters being those developed through evolution. -The chart shows each point which changes along the way to evolution, creating new species.

– Cladistics is the process of hypothesizing relationships (branches) between species

– Members share common ancestors– Can classify species into a specific genus– All organisms can be connected to one tree, but

they are separated into

Figure 14.25

All forms of genus share one common ancestor from eons ago, but many species have developed new traits that can put them in these different genera ranging from fish or mammals

Figure 14.26

Genera can be classified by specific traits that they have, like jaws or thumbs. For example, a shark and a dolphin may look similar in shape (pectoral and dorsal fins, tails) but they also have defining characteristics, like a sharks cartilage and a dolphin’s blowhole.