1. Organizing Life’s Diversity
Chapter 18

2. Classification
Grouping objects or organisms based on a set of criteria
Aristotle – plants and animals, “red blooded and bloodless.”
Further grouping based on physical characteristics
Did not account for evolutionary relationships

3. Carolos Linnaeus Based on morphology and behavior – five kingdoms
First formal system of taxonomy
Identifying, naming, and classifying species
18th century

4. Binomial Nomenclature
Genus + Specific epithet = Species
Drosophilia melanogaster
Homo sapiens
Up to whoever discovers it!
Why do we use scientific names?
Today we use evolutionary relationships to classify organisms

5. Taxonomic Categories Taxon – named group of organisms
Examples of taxa:
Domain - Eukarya
Kingdom - Animalia
Phylum - Chordata
Class - Mammalia
Order - Cetartiodactyla
Family - Balenopteridae
Genus - Balenoptera
Species – B. musculus
Who studies this? Systematists

6. What’s a species?
Typological species concept – based on physical similarities, assumes species are not evolving.
Biological species concept – able to interbreed and produce fertile offspring in a natural setting
Are exceptions (dogs and wolves)
Phylogenetic species
concept – classification is
determined based off
evolutionary history
Is this knowledge
complete?
Phylo – also called evolutionary classification

7. Characters
Scientists use characters, or inherited features, to construct patterns of descent
Morphological characters – homologous ones
Birds and dinosaurs both have hollow bones!
Biochemical characters – amino acids and nucleotides
Broccoli, cauliflower, and kale all look different, but have almost identical chromosome structure!
Molecular clocks – can compare two DNA sequences and their rate of mutation to determine how fast they’ve been evolving!
Therefore dinos are more like birds.

9. Cladistics
Classifies organisms in order of their divergence from a common ancestor
Cladograms – use derived characteristics!

10. Tree of Life, then and now
1879, Ernst Hackel

11. Domains and Kingdoms
In 1990, five kingdoms were reclassified due to the diversity in Bacteria
Domain Bacteria – peptidoglycan in cell wall
Kingdom Eubacteria
Domain Archaea – no peptidoglycan in cell wall
Kingdom Archaebacteria
Domain Eukarya – eukaryotes!
Kingdom Protista
Kingdom Fungi – are fungi considered autotrophs?
Cell Walls made of Chitin (different from plants and bacteria)
Kingdom Plantae
Kingdom Animalia
What about viruses?
Viruses – non-living

12. Eukarya

13. Basic Vocabulary/History
Producer/Autotroph – makes its own food, usually via photosynthesis
Produces oxygen that many other organisms need
Was oxygen always present on Earth?
Consumer/Heterotroph – get food by consuming other organisms
Decomposer – breaks down materials
Gets food and recycles nutrients
All organisms go through cellular respiration
Answer to question:

14. Comparing Features of Seed Plants
Kingdom Plantae
Comparing Features of Seed Plants
Feature
Seeds
Reproduction
Examples
Gymnosperms
Angiosperms
Bear their seeds on cones
Can reproduce without water; male gametophytes are contained in pollen grains; fertilization occurs by pollination
Conifers, cycads, ginkgoes, gnetophytes
Bear their seeds within flowers
Grasses, flowering trees and shrubs, wildflowers, cultivated flowers

15. Kingdom Animalia - Phylums
Phylum Porifera – sponges
Phylum Cnidaria – jelly fish, hydra, anenomes, coral
Phylum Platyhelminthes – flat worms (planaria)
Phylum Nematoda – round worms
Phylum Annelida – segmented worms (earth worms)
Phylum Mollusca – snails, clams, oysters, octopuses
Phylum Arthropoda - -pedes, insects, crabs
Phylum Echinodermata – sea stars, sea urchins

16. Phylum Chordata Includes humans! (in addition to many other organisms)
At some stage of life has…
hollow nerve chord- becomes and spinal chord
notochord – functions like a backbone (replaced by backbone in vertebrates)
Pharyngeal pouches (gills, we have them as embryos)
Tail beyond anus
Bilateral symmetry