1. shape of plants seed coat Shape of birds bill
Characteristic
Example/reason
Morphology
shape of plants seed coat
Shape of birds bill
Anatomy
Number of petals on a flower
Type of digestive system in invertebrate
Cytology
Structure and function of cells
Phytochemistry
Special organic compounds in plants
Chromosome number
Two species with same #, more closely related, the differing # of chromosomes
Molecular differences
Proteins
DNA sequences
Becoming the norm
5.4 Cladistics

2. Cladistics. classification that groups taxa
Cladistics classification that groups taxa together according to characteristics
Natural classification (related based off common descent)
Monophyletic: group composed of most recent common ancestor
Primitive traits (plesiomorphic) –
same structure and function
evolved early
Derived traits (apomorphic) –
same structure and function
evolved more recently
Determine ‘timeline’ of evolutionary past

3. Biochemical Evidence
Strong link to common ancestry
Most life uses left-handed proteins, select few (bacteria) use right-handed
Protein structure
All living species have same 20 amino acids
Can be transferred between organisms
DNA sequence
All living species using DNA for genetic information
Can be spliced between organisms

4. Phylogeny study of evolutionary past of species
Study using:
polypeptide sequences of certain proteins
Haemoglobin
Cytochrome c
chlorophyll
May support or refute current phylogeny trees – based of observable characteristics
More distant relations
Closely related

5. Evolutionary Clock - determined by steady, gradual accumulation of mutations over time
Mitochondrial DNA preferable:
Only mutations occur
Do not go through meiosis therefore no cross-over/random orientation occurring
Method: DNA hybridization
Match two different DNA strands
connection
repel
Using quantitative biochemical data estimate time of speciation
Check fossil evidence, radioisotope dating to confirm

6. Characteristics used to put species into appropriate clades
Homologous structures: common ancestor
Analogous structures: not derived from same ancestor

7. Cladogram – visual representation of evolutionary trends
Sister groups: closest relative
Clad
Outgroup: less related
Node: showing common ancestor
Primitive characteristics

8. Cladistics: study of clades
find most logical and natural connections between organisms to reveal evolutionary past
Working hypothesis:
Scientific
Lack integrity
Feathers? Bird?
Difference from Linnaean system
Hierarchical groupings unclear at times
Birds occupy own class (avian)
Several derived characteristics shared with dinosaurs
Fused clavicle
Flexible wrists
Hollow bones
Characteristic eggshell
Hip/leg structure
Parsimony  birds evolved from dinosaurs

9. Figwort family
Plantain family
New evidence requires reclassification
DNA analysis moved foxglove from figwort to plantain family though morphological features do not match
Foxglove

10. Reclassification of species – rearranges phylogenetic tree
Circumscription: place taxa to make monophyletic groups
Paraphyletic: species that should be on separate branches
Made into monophyletic groups