3. Classification of Life
What is Taxonmy? Video

4. Essential Questions
How can genetic and evolutionary relationships be used to classify organisms?
How can data and/or models be used to analyze how organisms are organized into hierarchy of groups and subgroups based on evolutionary relationships?

5. Classification of Life
Biologist classify, or group, organisms in a logical way that shows their relationships to other organism (similar to a family tree!)
Grouped according to various biological characteristics such as similarities in structures, biochemistry, genetics, embryological development and fossil evidence
Classification systems suggest that related organisms shared a common ancestor at some time in the past

6. Classification of Life
Classification – a system for grouping related organisms
Each organism has a scientific and common name:
Scientific name – unique and universal
Common name – vary among languages and regions
Scientific Name = Puma concolor
Common Names = Mountain Lion Cougar

7. Linnaeus’s System of Classification
Binomial nomenclature – each species is assigned a 2 part name (Bi = two)
First word refers to the genus
Second word refers to the species
Scientific names always written:
In italics
First word is capitalized
Second word is lowercase

8. Taxonomic Categories Organized least to most related  Phylum Class
Kingdom
Phylum
Class
Order
Family
Genus
Species

10. Major Kingdoms

11. Monera Primitive cell structure Lack a nuclear membrane
Lack organelles with membranes
Examples:
Bacteria
Blue-green Algae
Streptococcus pyogenes

12. Protista
Spirogyra algae
Mostly unicellular organisms with plant-like and/or animal- like characteristics
Algae - Plant-like in mode of nutrition
Protozoa - Animal-like in mode of nutrition
Examples:
Spirogyra (Algae)
Paramecium, Ameba (Protozoa)
Paramecium protozoa

13. Fungi
S. pombe (fission yeast)
Bread mold - Left
Cells are usually organized into branched, multinucleated filaments
Filaments absorb digested food from the environment
Examples:
Yeast
Bread mold
Mushroom

14. Plant Multicellular, photosynthetic organisms
Sphagnum moss (bryophytes)
Geranium pollen (tracheophytes)
Multicellular, photosynthetic organisms
Bryophytes - Lack vascular tissue; has no true roots, stems, or leaves
Tracheophytes - Have vascular tissue, true roots, stems or leaves
Examples:
Moss (Bryophytes)
Geranium flower, fern, bean, pine tree, maple tree, corn (Tracheophytes) m

15. Animals Multicellular organisms that ingest their food
Coelenterates – two cell layers, hollow body wit one opening (hydra, jellyfish)
Annelids – segmented body walls (earthworm)
Mollusks – one or two part shell (clam)
Arthropods – jointed appendages, exoskeleton (grasshopper, lobster, spider)
Chordates – dorsal nerve cord (shark, frog, human)

16. Animals
Hydra
Head of Earthworm
Bay scallop
Blue Spiny Lobster

17. Major Animalia Phyla

18. Patterns of Evolution
Coevolution – process by which two species evolve in response to changes in each other
Convergent Evolution – process by which organisms evolve structures that have similar (analogous) structures or functions in spite of their evolutionary ancestors being unrelated
Divergent Evolution – Process by which species diverges into two or more descendant species, resulting in once related species to become more unrelated

20. Cladistic Analysis Guided by Darwin’s Theory of Evolution:
Biologist now group organisms that represent lines of evolutionary decent, not just physical similarities
Cladistic Analysis – identifies and considers only characteristics that are evolutionary innovations (new characteristics that arise as lineages evolve over time)
Derived Characters – characteristics that appear in recent lineages but not in its older members

21. Genetics & Classification
Genes of many dissimilar organisms show important similarities at the molecular level
The genetic similarities can be used for classification
Molecular Clock – comparisons of DNA can be used to estimate the length of time that two species have been evolved independently
Degree of dissimilarity = indication of how long ago the two species shared a common ancestor