Modern Classification sorts organisms into groups shows relationships among them

1. Modern Classificationsorts organisms into groupsshows relationships among them Phylogeny Systematics Cladistics

2. Classification and Diversity Classification - tries to organize all living things into groups - show how they evolved from earlier life forms - show relationships to other present forms - changes with new information Early Systems Aristotle - by environment: land, water, air John Ray (1600s) - in related groups - short description for each species

3. Linnaeus Carolus Linnaeus – Swedish botanist, 1700s used physical appearance and structure • 7 taxa: from broad to specific • Kingdom – Phylum – Class – Order • - Family – Genus – Species Binomial Nomenclature - two names for each Genus: group to which it belongs species: 1-2 word description Ex. Homo sapiens

4. Evidence for Classification Many forms: - physical appearance and structure (morphology) - other present organisms - fossils - molecules, especially DNA, RNA, proteins - embryology patterns Various organizing diagrams

5. Evidence for Evolutionary Relationships • Physical appearance and structure • Resemblance to other organisms

6. Fossils Embryo Development

7. Phylogeny and Systematics Taxonomy – sort and name organisms Phylogeny - Evolutionary history of a group of organisms - shows common ancestry Systematics - combines taxonomy with evolution - organized way to study diversity and relationships

8. Taxonomy – sorting and naming Species – individual type of organism Genus – group of related species Scientific Name = Genus & species Family – related genera Order – related families Class – related orders Phylum – related classes Kingdom – related phyla Domain – Three Domain System

9. Phylogeny – evolution history

10. Simplest relationships make the most likely phylogenetic trees

11. Phylogeny -compares structure Homologous – similar structure, with adaptations - shows common ancestry

12. Analogous structures • Evolved in similar environments • NOT shared ancestry

13. Cladistics Tries to show evolutionary relationships based on physical traits shared by different groups of organisms

14. Cladograms More shared traits = more closely related Derived character – more recent branch from evolutionary line Primitive character - older, shared by more groups

15. Molecular Systematics • Compares molecules to find relationships

16. Student Mushroom Tulip Common ancestor Figure 15.9B • Ribosomal RNA • Have shown that fungi are more closely related to humans than to green plants

17. DNA – Compare genes and DNA sequences • - many similar sequences = closely related

18. Human Chimpanzee Gorilla Orangutan Common ancestor Figure 15.9C • More shared genes = closer relationship

19. Molecular Clocks • Some regions of DNA or proteins • Change at a fairly consistent rate • Can date evolutionary events

20. Five- Kingdoms System (Classification is a work in progress!) • Prokaryotes are in one Kingdom – Monera • Eukaryotes are grouped in separate kingdoms • Animals, Plants, Fungi, Protists

21. Six-Kingdom System • Bacteria are divided into two kingdoms, based on their chemical nature

22. Three Domain System • One domain for all eukaryotes • One domain for each of the two kinds of bacteria