Transcript

Modern Classificationsorts organisms into groups

shows relationships among them

PhylogenySystematics

Cladistics

Classification and DiversityClassification

- tries to organize all living things into groups - show how they evolved from earlier life forms- show relationships to other present forms- changes with new information

Early Systems Aristotle - by environment: land, water, air John Ray (1600s) - in related groups

- short description for each species

LinnaeusCarolus Linnaeus – Swedish botanist, 1700s used physical appearance and structure

Binomial Nomenclature - two names for each Genus: group to which it belongs species: 1-2 word description

Ex. Homo sapiens

7 taxa: from broad to specific Kingdom – Phylum – Class – Order - Family – Genus – Species

Evidence for ClassificationMany forms:

- physical appearance and structure (morphology)

- other present organisms

- fossils

- molecules, especially DNA, RNA, proteins

- embryology patterns

Various organizing diagrams

Evidence for Evolutionary Relationships

• Physical appearance and structure• Resemblance to other organisms

Fossils Embryo Development

Phylogeny and Systematics

Taxonomy – sort and name organisms

Phylogeny - Evolutionary history of a group of

organisms - shows common ancestry

Systematics - combines taxonomy with evolution

- organized way to study diversity and relationships

Taxonomy – sorting and namingSpecies – individual type of organism

Genus – group of related species

Scientific Name = Genus & species

Family – related genera

Order – related families

Class – related orders

Phylum – related classes

Kingdom – related phyla

Domain – Three Domain System

Phylogeny – evolution history

Simplest relationships make the most likely phylogenetic trees

Phylogeny -compares structureHomologous – similar structure, with adaptations

- shows common ancestry

Analogous structures– Evolved in similar environments– NOT shared ancestry

CladisticsTries to show evolutionary relationships based on physical traits shared by different groups of organisms

Cladograms

More shared traits = more closely related

Derived character – more recent branch from evolutionary line

Primitive character - older, shared by more groups

Molecular Systematics• Compares molecules to find relationships

Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings

• Ribosomal RNA

– Have shown that fungi are more closely related to humans than to green plants

Student Mushroom Tulip

Common ancestorFigure 15.9B

Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings

DNA – Compare genes and DNA sequences

- many similar sequences = closely related

Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings

More shared genes = closer relationship

Human Chimpanzee Gorilla Orangutan

Common ancestorFigure 15.9C

Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings

Molecular Clocks

• Some regions of DNA or proteins

– Change at a fairly consistent rate

– Can date evolutionary events

Five- Kingdoms System

• Prokaryotes are in one Kingdom – Monera• Eukaryotes are grouped in separate kingdoms

– Animals, Plants, Fungi, Protists

(Classification is a work in progress!)

Copyright © 2005 Pearson Education, Inc. Publishing as Benjamin Cummings

Six-Kingdom System

Bacteria are divided into two kingdoms, based on their chemical nature

Three Domain System • One domain for all eukaryotes

• One domain for each of the two kinds of bacteria


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