classification of life chapter 17. how classification began ▫classification-grouping objects or...

Classification of Life Chapter 17

How Classification Began

▫Classification-grouping objects or information based on similarities

▫Taxonomy- Branch of biology that groups and names organisms based on studies of their different characteristics

▫Aristotle’s System (384-322B.C.) Everything was either a plant or an animal System stood for centuries

Aristotle’s System- grouped by analogous structures

Linneaus’ system of Binomial Nomenclature

Based on physical and structural similarities (resulted in grouping that revealed relationships between organisms)

Explained evolutionary relationships Uses binomial nomenclature- 2 word naming

system Genus- 1st word, groups similar species Specific epithet(SPECIES) describes the

characteristics of the organism. Humans: Homo sapiens where

homo=genus, sapiens= wise (Greek)

Scientific vs. Common Names Latin is language of taxonomists Common names- common to area they are found.

•Example: Car Hood (USA) = Bonnet (Britian)

Flashlight (USA) vs. Torch (Britian)

Modern Classification: TAXONOMY•Uses underlying evolutionary

relationships as well as external and internal relationships

•How it works: A framework (are dinosaurs more closely

related to reptiles or birds?) Useful tool- helps to identify unknown

species Helpful in Economy- Knowing pine trees

contain a useful substance for disinfecting may lead to finding another disinfectant in a similar species.

TAXONOMIC RANKINGS•Larger taxa- broad groups ie. Animal Kingdom•Smallest taxa- more specific, organisms can

interbreed and produce viable offspring. Kingdom- largest division 6 total Phylum- similar classes- in plant kingdom may call

it divisions Class- similar orders Order- similar families Family – similar genus Genus- similar species Species- most specific, can interbreed.

7 TAXA Kingdom- largest division 6 total Phylum- similar classes- in plant kingdom may call it divisions

Class- similar orders Order- similar families Family – similar genus Genus- similar species Species- most specific, can interbreed.

Problem solving lab 17.1

Determining Evolutionary Relationships

1.Structural similarities- may imply a shared ancestor. If you observe an unknown with retractable claws you will put them in the cat family.

2.Breeding behavior- may differentiate among species (ie. Hyla versicolor and Hyla chryosocelis)

3.Geographical Distribution- Location of the species on the Earth.

Evolutionary relationships cont…

4. Chromosome Comparison Banding in metaphase 1 Size of chromosomes Position of the centromere

5. Biochemistry DNA sequences Proteins found Nucleotide sequences

Phylogenic Classification Models•PHYLOGENY- evolutionary history of an

organism. Species with the same ancestor , share and evolutionary history.▫Cladistics

System of classification based on phylogeny Assume organisms diverge from a common

ancestral group. CLADOGRAM (fig 17.7) – model of phylogeny

of species. Similar to a family pedigree

•CLADOGRAM

Velociraptor

Archaeopteryx

Robin

Light bones3-toed foot;

wishbone Down feathers

Feathers withshaft, veins,and barbs

Flight feathers;arms as long

as legs

Theropods

Allosaurus

Sinornis

Phylongeny cont…

▫Fanlike Model (fig 17.8)- Give more information than a cladogram Phylogeny Time Extinction Anatomy Genetics Etc…

•6 kingdoms: Eubacteria, Archaebacteria, Protists, Fungi, Plants, Animals

Six Kingdoms of Organisms

Arranged based on:• 1. Organization (uni/multicell) •2. How they obtain energy or eat.

(heterotroph, autotroph) •3. Prokaryotic or eukaryotic- complexity

of cell structure.

Prokaryotes:

▫Prokaryotes: MONERANS Microscopic Unicellular No distinct nuclei Organelles are not membrane bound

organelles.•Heterotrophs or Autotrophs (may be

photosynthetic or chemosynthetic

2 kingdoms of prokaryotes:MONERANS1. ARCHAEBACTERIA- most live in

extreme environments without oxygen. Example: ocean depths, swamp, volcano

2. EUBACTERIA- 5000 species, strong cell walls, complex genetic make-up, most are harmless, some cause disease, for example ,strep throat.

3. Protist kingdom- Eukaryotes Eukaryotic but lack complex organ systems

Live in moist environments (pond scum)

Uni /multicellular Plant like autotrophs Animal like heterotrophs Fungus like- heterotrophs with reproductive structures like fungus.

Cilia

Oral groove

Gullet

Micronucleus and macronucleus

Contractile vacuole

Anal pore

4.Fungus- earth’s decomposers Heterotrophs that DO NOT move from place to place

Multicellular (except yeast) Eukaryotic Absorbs nutrients form organic material in environment

50,000 known species

5. Plants

MulticellularPhotosynthetic eukaryotes Produce oxygenCell walls and chloroplasts typical

Mosses , ferns and evergrees250.000 known species

6. Animals

Multicellular consumers(heterotrophs)

Nearly all mobileDO NOT have cell wallsOrganization: CellsTissuesorgansorgan systemsorganism