18-1 Finding Order in Diversity Slide 1 of 26 Classification of Living Organisms Lecture 3 Copyright Pearson Prentice Hall

18-1 Finding Order in Diversity Slide 2 of 26 Copyright Pearson Prentice Hall Aristotle’s 1 st system of classification was based on: Plants: structure Animals: habitat Linnaeus’ system was based just visible structures called: Morphology -study of form/structure

18-1 Finding Order in Diversity Slide 3 of 26 Taxonomy: The modern day system for studying and classifying living organisms. Copyright Pearson Prentice Hall

Slide 4 of 26 Copyright Pearson Prentice Hall Modern scientist who classify, taxonomist, use the following: 1. Homologous Structures -Homo means… -the same -similar structures with different functions

Slide 5 of 26 Copyright Pearson Prentice Hall Penguin flipper used for swimming Alligator fore arm used for walking Bat wing used for flying Human fore arm for gathering

Slide 6 of 26 Copyright Pearson Prentice Hall 2.Evidence from Genetics/Biochemistry -common or similar DNA codes. -common or similar proteins Analysis of the DNA sequence determined that the monkey's DNA code is about 93 percent similar to the human DNA code.

Slide 7 of 26 Copyright Pearson Prentice Hall 3. Similarities in embryonic development.

Slide 8 of 26 Copyright Pearson Prentice Hall Phylogenic Tree know as: - evolutionary tree or -tree of life

Slide 9 of 26 New Classification Schemes Copyright Pearson Prentice Hall Taxonomy: -is the study of classification -to organize all living organisms based on their morphology (structures) and phylogeny (evolutionary trend) Phylogeny: -Is the evolutionary history of a species.

Slide 10 of 26 Copyright Pearson Prentice Hall Two approaches to Phylogenetic Classification: 1.Creating a Phylogenic Tree -Each successive group, taxon, should be represented by finer and finer branches all stemming from a common ancestor. Creates a “tree of life”. -branches based on: *biochemical evidence *homologous structures *common embryology

Slide 11 of 26 Copyright Pearson Prentice Hall

Slide 12 of 26 Copyright Pearson Prentice Hall

Slide 13 of 26 Copyright Pearson Prentice Hall 2. Creating a cladogram Uses certain features of an organism called shared derived characteristics. Shared derived characteristics are features that apparently evolved only within the group under consideration. Example: Feathers….. birds are the only animals that have feathers therefore it separates it from all other vertebrates.

Slide 14 of 26 Copyright Pearson Prentice Hall

Slide 15 of 26 Copyright Pearson Prentice Hall

Slide 16 of 26 Complete Activity #3 Copyright Pearson Prentice Hall