Presentation on theme: "Classifying the Diversity of Life – Systematics: Study of the diversification of living forms, both past and present, and their relationships – Taxonomy:"— Presentation transcript:
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 Classification Domain: Bacteria Archaea Eukaryota Kingdom: Animalia Plantae Fungi Protista Archaea Bacteria DomainHighest/ largest classification Eukarya KingdomKingdom is put into Domain Animalia PhylumPhylum is put into kingdom Chordata ClassClass is put into phylum Mammalia OrderOrder is put into class Carnivora FamilyFamily is put into order Felidae GenusGenus is put into family Felis SpeciesName of speciesFelis 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.