Module 3 – Variety of Organisms

Taxonomy – the branch of biology concerned with naming and classifying the diverse forms of life.

Carolus Linnaeus/Carol von Linnae (1707-1778)
 - Swedish physician and botanist
 - sought to discover order in the diversity of life “for the greater glory of the Lord”
 - divided life between plants and animals
 - developed the two part or binomial system of naming organisms according to genus and species that is still used today

Robert H. Whittaker (1969)
-    led a team of researcher from Cornell University.
-    proposed a 5-kingdom system: Monera, Protista, Plantae, Fungi, and Animalia

Carl Woese (1977)
- added Archaea as a sixth kingdom
- redefined his classification to three domains in 1990: Bacteria, Archaea and Eukarya.

* taken from wikipedia.com

Taxonomic Classification
Domain
Kingdom
Phylum
Class
Order
Family
Genus
Species

Mnemonic: Do Kings Play Chess On Fine Grain Sand? 

2 Types of cells
1. Prokaryotes – no nucleus and has single loop of DNA
2. Eukaryotes – has nucleus, DNA is longer and contain more information, has a lot of organelles

Bacteria/Eubacteria – Prokaryotes
-    Rarely have organelles
-    Often motile using pili or flagella
-    Peptidoglycan (a kind of protein) in cell wall
-    Can be found in many different shapes and sizes
-    Can be found in almost any environment
-    Ex. E. coli

Archaea – Prokaryotic organisms
-    Mostly inhabit extreme environments (extremophiles)
-    Archaean groups based on environmentsal criteria
1.    Methanogens – obtain energy using CO2 to oxidize H2 producing methane; live mostly in swamps and marshes where there is little oxygen
2.    Halophiles – live in saline places. Some just tolerate salinity while some require a degree of salt to be present to survive.
3.    Thermophiles – thrive in hot environments
4.    Alkaliphiles/Acidophiles – thrive in basic or acidic environments.
- ex. Sulfulobulos

Protists – mostly unicellular eukaryotes
-    maybe several kingdoms within Domain Eukarya
-    Some make food by photosynthesis (algae)
-    Some are heterotrophic and eat bacteria and other protests
-    Can be heterotrophic or autotrophic
-    Some protests are fungus-like
-    Ex. Amoeba, brown algae, Diatoms, Trypanosoma

Fungi – heterotrophic eukaryotes that digest their food externally and absorb externally and absorb the nutrients.
-    usually consists of a mass of threadlike hyphae called a mycelium
-    ex. Yeast, Button mushrooms, truffles

Plants – multicellular eukaryotes that make organic molecules by photosynthesize.
-    have fortified cell well (lignin)
-    obtain nutrients in two media (air and water)
-    ex. Trees, shrubs, grasses

Animalia – are multicellular, heterophic and lack cell walls
-    held together by extracellular structural proteins and by unique type of multicellular junctions
-    reproduce sexually

Modes of Nutrition among Living organisms.

Comparisons among the three domains