1. Classification of Life

2. Why Classify? There are more than 2 ½ Million species of organisms on earth – and more to be discovered! When you go into the grocery store, how do you know where to find the dairy, meat, cereals, etc...? We need some system to help organize the classification of living things How do you know that a dog and a wolf are related.

3. We talked about relationships during the last chapter. How can we use those ideas to help us place organisms into a logical order? Accepted biological classification systems: They assign a single universally accepted name to each organism. Why? They can discuss with scientists from other countries or across the street. They place organisms into groups that have real biological meaning.

4. Biological Classification Aristotle was one of the first people to classify organisms. His categories included only 2 categories - plants and animals. By 19th century, scientists began using Latin or Greek words to name organisms, but Great detail was used “Oak with deeply divided leaves that have no hairs on the underside and no teeth around their edges” may have been one tree’s name.

5. ??? Caused confusion: Scientists might call characteristics different things – serrated edge or saw tooth Organisms may have more than one name

6. Carolus Linnaeus Swedish Botanist Binomial Nomenclature – two names for each organism Pagurus longicarpis, Acer palmatum, Homo sapien

7. Genus and species – Genus is capital, species is lower case, both are italicized or if you write them down, they should be underlined. After naming organisms, Linnaeus grouped them together based on body structures they shared. Groups of organisms are called taxa (singular is taxon). The science of naming organisms is called taxonomy. Smallest taxon is species – a group of similar looking organisms that can breed and produce fertile offspring

8. What is a species? If two species share the same characteristics, but are distinct, they may belong to the same Genus.

9. What is a species? Felis domesticus (common house cat), Felis concolor (mountain lion)

10. What is a species? Lions (Panthera leo) and tigers (Panthera tigris) are still cat like, but different enough to be classified as different Genus.

11. DaringDomain King Kingdom Philip Phylum Came Class Over Order For Family Great Genus Spaghettispecies

12. Taxonomy Today Not always so cut and dry. Species breed with each other – they share a common gene pool

13. Above that, there is not a clear biological identity Sometimes organisms are “moved” from one to another classification 6 Kingdom System

14. Over the years, it became obvious that 2 kingdoms were not enough. Microscopic organisms looked and acted different than other organisms Euglena Bacteria – lack nuclei, mitochondria, chloroplasts

15. Classification is based on Structural similarities –presence of many shared physical traits implies close relationship –dandelions and sunflowers have same flower and fruit structure Breeding Behavior –frogs that live in the same areas and look similar but males make different sounds to attract mates and only mate with members of their own group = different species

16. Classification is based on Geographical distribution –Darwin’s finches Chromosome comparisons –# and structure of chromosomes –cauliflower, cabbage, kale, and broccoli look different, but have almost identical chromosomes Biochemistry –DNA sequences compared

17. Cladistics – system of classification based on evolutionary relationships Cladogram – model of phylogeny –A method used to construct a hypothetical evolutionary tree

18. Domains Largest group – even larger than kingdom 3 domains –Archaea –Bacteria –Eukarya

19. Bacteria –prokaryotic –cell walls with peptidoglycan –Unicellular –can be autotroph or heterotroph –what we think of as bacteria

20. Archaea –cell walls lack peptioglycan –prokaryotic –unicellular –autotroph or heterotroph –Live in extreme environments –have DNA

21. Eukarya fungi plantae animalia

22. Fungi mold, yeast, mushrooms cell wall w/out cellulose heterotrophic many nuclei do not always have separate cells divided by complete cell walls

23. Plantae multicellular cell walls with cellulose autotrophic – photosynthesis using chlorophyll

24. Animalia multicellular heterotrophic cell membranes – no cell walls

25. Taxonomy is not constant. What was once 2 kingdoms was found to be inadequate, now there are 3 Domains and 6 kingdoms. Algae have been classified as plants, then protists, now plants again.