1. Classification Systems
- Taxonomy

2. Why Classify? 2.5 million kinds of organisms
Not complete- 20 million organisms estimated
Must divide into manageable groups
To work with the diversity of life we need a system of biological classification that names and orders organisms in a logical manner

3. Why Classify? Assign a universally accepted name to each organism
Place organisms into groups that have real biological meaning
Organisms share important traits with members of the same groups

4. Biological Classification
Eighteenth century European scientists used Latin or Greek words to name organisms instead of local languages
Very long descriptive names
Difficult to standardize – different names

5. Carolus Linnaeus
Developed a system of naming plants and animals that we use today
Swedish botanist
Binomial nomenclature – gave each organism a two-part scientific name
Genus and species - Acer rubrum – red maple
Acer is genus of all maple trees
Red in Latin is rubrum

6. Classification System of Linnaeus
Universally accepted
Groups that have shared characteristics are grouped into the same taxa
Taxonomy – the science of naming organisms and placing them into taxa – taxon is singular

7. Taxonomy
The smallest taxon is species – a population of organisms that share similar characteristics and can breed with one another.
Kingdom – Phylum- Class – Order- Family – Genus – species
Each taxa may also have sub groups or super groups

8. Geographic Isolation – physical barrier
Reproductive Isolation- reproductive barrier – not always complete and can result in hybrids

9. Taxonomy Today A very difficult science
Has changed greatly since Linnaeus
The only taxon with clear biological meaning is the species – share a common gene pool – because they interbreed
All other taxa are determined by scientists

10. Taxonomy Today Living species have evolved from earlier species
Guiding philosophy for classification
Organisms grouped to show evolutionary relationships
Homologous structures
Developing embryos
fossils

11. Phylogeny Evolutionary history of a species
Overall similarity between characteristics of different kinds of organisms
Relates extant and extinct species
Looks at homology- similar characteristics from a common ancestor.

12. Convergent evolution – similar traits that evolve independently such as wings-these characters are called analogous characters
This can confuse taxonomy

13. Cladistics
System of taxonomy that reconstructs phylogenies by inferring relationships based on similarities
Used to determine the sequence in which different groups of organisms have evolved

14. Focuses on a set of unique characteristics found in a particular group of organisms or derived traits.
Looking at shared derived traits a cladogram is made
Morphology, physiology, molecular traits, and behavioral traits are studied

15. Species shown to be closely related are classified together
Other species that may look alike but possess analogous structures are classified in diff groups

16. Morphology
Comparitive morphology – (includes embryology) – examines the varying shapes and sizes of organismal structures – includes developmental origins
Variations in skull bones, limb bones, scales, feathers hair etc.

17. Comparitive biochemisry
Amino acids
Proteins
Nucleotides
Cytochrome C is slightly different in different organisms.

18. Comparitive cytology Variation in numbers, shape, sizes of chromosomes
Used on living organisms

19. The Kingdoms of Life Eubacteria – bacteria
Protista – one celled organisms
Fungi – mushrooms, mold, ringworm,
Plantae- plants
Animalia – animals
Archaebacteria – new kingdom previously part of monera

20. Eubacteria Prokaryotes – have no nucleus 0ne celled prokaryotes
Mostly heterotrophic – does not make own food
Cell wall – made of lipid and carbohydrates
3 cell shapes – spirilla, cocci, and bacilli

21. Protista Eukaryotic – cells have a nucleus
Can be heterotrophic or autotrophic
Animallike, plantlike, or funguslike
Amoeba, paramecium, euglena
Single celled organisms

22. Fungi Heterotrophic – do not make their own food
Cell walls – made of chitin
Eukarotic – have a nucleus
multicellular

23. Plantae Autotrophic – make own food – photosynthesis
Eukaryotic – have a nucleus
Multicellular
Cell wall – made of cellulose

24. Animalia Heterotrophic – do not make own food
Eukarotic – have a nucleus
No cell walls
Multicellular