Chapter 18 Classification. Classifying A great diversity of organisms requires a universal way to...
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Transcript of Chapter 18 Classification. Classifying A great diversity of organisms requires a universal way to...
Chapter 18 Classification
Classifying• A great diversity of organisms requires a universal
way to name them• Taxonomy – allows biologists to name and classify
organisms in a logical manner- usually based on similarities and
differences in appearanceEx: teachers and mechanicsvs. biology teachers and auto mechanics
Scientific Naming• Carolus Linnaeus – Swedish botanist brought order and
devised a system for naming and categorizing organismsBinomial Nomenclature – two word system of
scientific nameGenus (capitalized and italized) – depicts species
association- Specific epithet (lower case italized) – unique species within genusEx: Ursus arctos Canis familiaris
Hierarchical Classification• System of levels that categorize organisms in
increasingly more specific groups- Broad at the top to most specific at the bottom- Organisms grouped at the bottom share more common characteristics compared to organisms near the top
Hierarchical ClassificationDomain - 3 domains (Eukarya, Bacteria, Archaea)
Kingdom – 4 kingdoms within EukaryaPhylumClassOrderFamilyGenusSpecies
Hierarchical Classification
Classification
Evolutionary Classification• Phylogeny- grouping organisms into categories
that represent lines of evolutionary descent- Refers to the evolutionary history of a species or group of species- Usually constructed from fossil record to describe origin.
Cladograms• Cladistic analysis - identifies characteristics that are new
and innovative as lineages of a species evolved over time• Derived characters – features that appear in recent parts
of lineage but not in older members• Cladogram – diagram that shows evolutionary
relationship among groups of organisms- depicts patterns of shared characteristics- useful in understanding how one lineage branched
from another- resembles a family tree
Cladograms
Cladograms
DNA & RNA• Organisms of different anatomies can have
common traits – How?• All organisms use DNA and RNA to pass on
information and to control cell growth and development.
• Genes can show similarities at the molecular level and can help determine classification and evolutionary relationships
Molecular Clocks• Molecular clocks - use DNA comparisons to
estimate the length of time that 2 species have been evolving independently- relies on mutations to indicate time- DNA sequences of 2 species can show dissimilarity- any degree on difference indicates how long ago the 2 species may have shared a common ancestor
Domains• Bacteria
- unicellular and prokaryotic- thick, rigid cell wallsKingdom – Eubacteria- diverse organisms that are both free living and deadly parasites- some are photosynthetic- some require oxygen, other are anaerobicEx: E. coli, Streptococcus
Domains• Archaea
- unicellular and prokaryotic- extremophiles- live in extreme habitats
1. thermophiles - volcanic hot springs ( hydorthermal vents)
2. Halophiles - Brine pools (Dead sea)
3. Methanogens – black organic mud (sewage treatment)
Domains• Eukarya
Eukaryotic – unicellular and multicellular4 Kingdoms
1. Protista – paramecium, green algae 2. Fungi – yeast, mushrooms3. Plantae – cell walls, chloroplasts4. Animalia- you