10.2 The five kingdoms Flashcards
How where living organisms orginally classified?
2 kingdoms plants and animals
Who first classified animal speces in History of animals and what was the name of his pupil who wrote a parallell work, History of Plants and what did this theorise?
Aristotle (384BC) and Theophrastus (371-287BC), Theorised that the animal kingdom included every libving thing that moved, ate and grew to a certain size then stopped growing while the plant kingdolm included every living thing that did not move or eat yet continued to grow throughout life.
Why was classification brought about and what enabled this?
As more was discovered about organisms and more species were discovered, it becam increasingly difficult to divide living organims into just two kingdoms. For example the introduction of the microscope in the 16th to 17th century enabled scientists to study the cells of an organism and showed that bacteria have a very different cell structure to that of other organisms.
When did scientist begin to classify organims into frive kingdoms and who intoduced this system?
From the 1960s, scientists classified organisms into five kingdoms. This classification system was introduced by Robert Whittaker, an American plant ecologist, based on the principles developed by Carl Linnaeus.
What are the five kingdoms that living ogranisms can be classified in?
And how where they classified generally?
** = prokaryotes * = eukaryotes
* * Prokaryotae (bacteria)
* Protocista (the unicellular eukaryotes)
* Fungi (e.g. yeasts, moulds, and mushrooms)
* Plantae (the plants)
* Animalia (the animals)
Classified orginally based on similarities in thier observable features
General features and examples of Prokaryotae?
gen ft:
- unicelllular
- no nucleus or other membrane-bound organelles - a ring of ‘naked’ DNA (plasmids) - small ribosomes
- no visible feeding mechanism - nutrients are absorbed through the cell wall or produced internally by photosynthesis
examples:
- Escherichia coli
- Staphylococcus aureus
- Bacillus anthracis
General features and examples of Protocista?
General Ft:
- (mainly) unicellular
- a nucleus and other membrane-bound organelles
- some have chloroplasts
- some are sessile, but others move by cillia, flagellla, or by ameboid mechanisms
- nutrients are acquired by photosynthesis (autrophic feeders), ingestion of other organisms (heterotrophic feeeders), or both - some are parasitic
Examples:
- Species belonging to the genera *Paramecium *and Amoeba
General features and examples of Fungi?
General Ft:
- unicellular or multicellular
- a nucleus and other membrane-bound organelles and a cell wall mainly composed of chitin
- no chloroplasts or chlorophyll
- no mechanisms for locomotion
- most have a body or mycelium made of threads or hyphae
- nutrient are acquires by absorption - mainly from decaying material - they are saprophytic feeders - some are parasitic
- most store thier food as glycogen
Examples:
- mushrooms
- moulds
- yeast
General features and examples of Plantae?
General Ft:
- over 250,000 species, the second largest of the kingdoms
- multicellular
- a nucleus and other membrane-bound organelles including chloroplasts, and a cell wall mainly composed of cellulose
- all contain chlorophyll
- most do not move, although gametes of some plants move using cillia of flagella
- nutrients are acquired by phtosynthesis - they are autotrophic feeders - organisms that make thier own food
- store food as starch
General features and examples of Animalia?
General Ft:
- largest kingdom with over 1 million known species
- multicellular
- a nucleus and other membrane-bound organelles (no cell walls)
- no chloroplasts
- move with the aid of cilia, flagella, or contractile proteins, sometimes in the form of muscular organs
- nutrients are acquired by ingestion - they are heterophic feeders
- food stored as glycogen
How and why have there been recent changes to classifictaion systems?
As scientests lerant more about organims systems have changed due to the study of genetics and otehr biological molecules, allowing study of evolutionary relationships between organisms allowing classification. As organisms evolve, internal and external fetaures change aswell as DNA as this dteermines the porteins made and thus the characterstics of the organism. By comparing DNA / proteins you can discover similarities and evolutionary relationships.
What is the current classification systme used by scientist and who pruposed it?
Three Domain system proposed by Carl Woese, an american microbiologist in 1977, reusing the word kingdom which has now changed to domain as a duther levle of classification at the top of the heirarchy.
How does Woese’s system group organisms?
By using differences in the sequences of nucleotides in the cells rRNA, the cells memebrane lipid structure and their sensitivity to antibiotics.
Classifies into 3 domains
- Archea
- Bacteria
- Eukarya
And 6 kingdoms
each organims domain contains a unique form of rRNA and different ribsomes.
How are Eukarya identified?
- 80s ribosomes
- RNA polymerase (responsible for most mRNA transcription) contains 12 proteins.
How are Archea identified?
- have 70s ribosomes
- RNA polymerase of different organisms conatins between 8 and 10 proteins and is very similar to eukaryotic ribosome
