New York State Lab

Relationships and Biodiversity

Pre-lab Review

Evolution

• Gradual change over time• If two organisms share similarities, they are likelyrelated – share a commonancestor• The more similarities, themore closely related

Evidence of Evolutionary Relationships

• Structural evidence:– Comparative anatomy• Homologous structures• Vestigial structures

– Comparative embryology

Evidence of Evolutionary Relationships

• Molecular evidence:– Comparative Biochemistry• Similar pigments (in plants)• Similar enzyme-controlled chemical reactions• Similarities in DNA structure• Similar proteins

Structural Evidence in Plants• External structure• Seeds• Internal structure:– Conducting tissue – carries materials– Xylem – carries water and nutrients– Phloem – carries food

Molecular Evidence in Plants• Pigments – absorb light• Chromatography – lab technique to separate

pigments in plants

Molecular Evidence in Plants• Enzymes – speed up chemical reactions• Enzymes are specific

Molecular Evidence in Plants – Enzymes

Molecular Evidence in Plants

• Gel electrophoresis – labtechnique to separatefragments of DNA fromorganisms

Molecular Evidence in Plants – Gel Electrophoresis

Molecular Evidence in Plants• Similarities in DNA code for amino acid

sequence in particular proteins

Molecular Evidence in PlantsProtein Synthesis

Molecular Evidence in Plants