Unit 5: The Diversity of Life

Chapter 22: Systematics (Classification)

Systematics

The scientific study of the diversity of organisms and their evolutionary relationships Taxonomy – the science of naming,

describing, and classifying organisms Classification – arranging organisms into

groups based on their similarities, which reflect historical relationships among lineages

Binomial Nomenclature

Carolus Linnaeus simplified the complicated, older system of classification

Binomial System of Nomenclature Makes classification an

international science Each species assigned a

two-part name

How to Write Scientific Names

1. First part of a scientific name = genus

2. Second part of scientific name = specific epithet

3. Genus name is always capitalized.

4. Specific epithet is not capitalized.

5. Scientific names are typed in italics

6. Scientific names are underlined (separately) if handwritten

7. Ex. Scientific name for dog

Canis familiaris or Canis familiaris

Taxonomic Levels

Domain Kingdom Phylum Class Order Family Genus Species

*A taxon is a formal grouping of organisms at a specific level, such as the genus.

Domains and Kingdoms

3 Domains: Archaea

Kingdom Archaebacteria Eubacteria

Kingdom Eubacteria Eukarya

Kingdom Protista Kingdom Fungi Kingdom Plantae Kingdom Animalia

Kingdom Archaebacteria

Prokaryotes Unicellular Microscopic Peptidoglycan absent in cell walls Differ biochemically from eubacteria Ecological Role:

Live in extreme environments: Methanogens – sewage, swamps Halophiles – salty environments Thermophiles – hot, acidic environments

Kingdom Eubacteria

Prokaryotes Unicellular Microscopic Cell walls composed of peptidoglycan Ecological Role:

Most are decomposers Some chemosynthetic Some photosynthetic Important in recycling nitrogen

Kingdom Protista

Eukaryotes Mainly unicellular or simple multicellular 3 informal groups:

Protozoa Algae Slime Molds/Water Molds

Ecological Role: Protozoa - Zooplankton Algae - Important producers Important oxygen source

Animal-Like Protists: Protozoans

Plantlike Protists: Unicellular Algae

Plantlike Protists: Red, Brown, & Green Algae

Kingdom Fungi

Eukaryotes Heterotrophic Absorb nutrients Cell walls of chitin Body composed of threadlike hyphae that form tangled

masses that infiltrate food Ecological Role:

Decomposers Some parasitic Used as food Yeast – bread and alcohol Drugs – antibiotics Spoilage, Crop loss

Sac Fungi

Club Fungi

Symbiotic Relationships

Lichens – symbiotic relationship between fungus and photosynthetic organism Pioneer species

Kingdom Plantae

Eukaryotes Multicellular Photosynthetic Multicellular reproductive organs Alternation of generations Cell walls of cellulose Ecological Role:

Primary producers Source of oxygen in atmosphere

Types of Plants

The Animal Kingdom

Which of these is an animal?

Kingdom Animalia

Eukaryotes Multicellular heterotrophs Complex organ systems Ability to move Specialized nervous tissue Ecological Role:

Consumers Herbivores, carnivores, or detritus feeders

Amazing Fact!

95% of animals are invertebrates Only 5% of animals are vertebrates

7 Essential Functions of Animals

1. Feeding

2. Respiration

3. Circulation

4. Excretion

5. Response

6. Movement

7. Reproduction

Phyla of Animals

Porifera - sponges Cnidaria – jellyfish, sea anemone Platyhelminthes – flatworms Nematoda – roundworms Annelida – segmented worms Mollusca – mollusks: octopus, snail, clam, oyster Arthropoda – scorpions, crab, all insects Echinodermata – sea stars, sea urchins Chordata – fish, reptiles mammals, amphibians,

birds

Your Assignment

Research 10 different organisms and record their classification levels Domain Species Name (genus and specific

epithet) 9 must be from the different phyla of animals,

the 10th can be from any other kingdom. Due tomorrow!

Phylogeny

Goal of systematics is to determine phylogeny – evolutionary relationships Homology – implies evolution from a common

ancestor Shared ancestral characters – suggest a distant

common ancestor Shared derived characters – indicate a more recent

common ancestor Molecular systematics – compares DNA for

assessing evolutionary relationships

Cladograms

Diagrams that illustrate phylogeny Base of cladogram – common ancestor for all

taxa being analyzed Branch point (node) – immediate common

ancestor of the next group Example cladograms p.480