Make observations about the following objects Make observations about the following objects. Classify them into three groups.

Classification = grouping of objects by similarities Taxonomy = branch of biology that groups and names organisms based on the different characteristics

Aristotle’s System Greek philosopher (384-322 BC) 1st to develop a system of classification Grouped organisms as either plants or animals and then by habitat and physical appearance Useful, but not in an evolutionary sense

Linnaeus’s System Swedish botanist (1707-1778) Developed method that is still used today Based classifications on physical and structural similarities

Modern Classification 2-word naming system = Binomial Nomenclature Identifies species Written in Latin= dead language and never changes 1st word = Genus; group of similar species 2nd word = species; specific characteristic Example = Homo sapiens

Scientific Names Canis familiaris = dog Felis domesticus = house cat Canis lupus = wolf Who is most closely related???

Scientific Names Common names can be very misleading

Dichotomous Keys Used to identify species by characteristics A set of paired questions to be answered as either yes or no

Relationships between organisms Phylogeny = the study of evolutionary relationships Cladistics = diagram that depicts evolutionary relationships among groups. It is based on phylogeny In the past, biologists would group organisms based solely on their physical appearance. Today, with the advances in genetics and biochemistry, biologists can look more closely at individuals to discover their pattern of evolution, and group them accordingly - this strategy is called EVOLUTIONARY CLASSIFICATION

A cladogram shows the evolutionary relationships between groups of living things. It is like a family tree for species. Section 17.2 Summary – pages 450-459

How to read a cladogram… The closer two species are on the cladogram, the more closely they are related. This means they evolved apart more recently. Sometimes a cladogram will also list the characteristics that make two groups or organisms different.

How evolutionary relationships are determined? Structural similarities Breeding behavior Geographical location Chromosome comparisons Biochemistry

7 Taxa (levels) of organization From broadest to most specific Taxon: Example: Kingdom Animalia Phylum Chordata Class Mammalia Order Primata Family Hominidae Genus Homo Species sapien

Six Kingdoms Animalia – animals – multicellular – largest kingdom with over 1 million known species Plantae – plants – multicellular - autotrophs Archaebacteria – unicellular , found in extreme environments like thermal vents with high heat and no oxygen Eubacteria – majority of bacteria we are familiar with fall into this category Fungi – includes, mushrooms, mold, mildew; are considered to be decomposers Protists – unicellular, includes diatoms, protozoa

Cell Type (Prokaryote or Eukaryote) Kingdom Info Cell Type (Prokaryote or Eukaryote) Body Form (Unicellular or Multicellular) Obtaining food (autotroph or herterotroph) Presence of complex body organs? (Y or N) Archeabacteria Ex: Eubacteria Protists Fungi Plants Animals