4.2.2 - Classification And Evolution (set A - Classification Systems) Flashcards
What is classification?
The name given to the process by which living organisms are sorted into groups - organisms within each group share similar features
Give 3 reasons whys scientists classify organisms?
- to identify species - by using a clearly defined system of classification the species an organism belongs to can easily be identified
- to predict characteristics - if several members in a group have a specific characteristic it is likely that another species in the group will have the same
- to find evolutionary links - species in the same group probably share characteristics because they have evolved from a common ancestor
can allow scientists to share research globally
explain how organisms are classified by the classification system?
First separated into 3 domains (Archaea, Bacteria and Eukarya) - moving down the hierarchy there are more groups at each level but fewer organisms in each, organisms in the same group share similar characteristics
- system ends with organisms being classified as individual species
what are the 3 domains?
Archaea, Bacteria and Eukarya
Define species?
A group of organisms that are able to reproduce to produce fertile offspring
Outline the 7 levels of hierarchy?
domain
- kingdom
- phylum
- class
- order
- family
- genus
- species
King Phillip Calls Out For Good Soup.
Explain how animals were classified before classification systems?
Organisms were given names according to physical characteristics, behaviour or habitat (eg blackbirds or song thrushes) - known as their common names
Explain the problem with using Common names for organisms?
Not useful for scientists working internationally, as organisms have more than one common name and different names in different languages
- also does not provide information about the relationship between organisms
binomial nomenclature developed to fix this
Explain how carl Linnaeus binomial nomenclature works?
All species given a specific name consisting of two parts
- first word - indicates the organism genus (called the generic name)
- second word - indicates the organism species (called specific name
written in italics or underlined
What are the 5 kingdoms?
- Prokaryotae
- Protoctista,
- Fungi
- Plantae
- Animalia
organisms originally classified into these kingdoms based on similarities in their observable features
Outline the general features of prokaryotae?
- unicellular
- no nucleus or other membrane bound organelles
- small ribosomes
- no visible feeding mechanism - nutrients absorbed through cell wall or produced via photosynthesis
Example include bacteria (E. coli)
Outline the general features of protocista?
- mainly unicellular
- nucleus or other membrane bound organelles
- some have chloroplast
- some move by cilia or flagella
- nutrients acquired by photosynthesis or ingestion of other organisms
Example include species belonging to Amoeba
Outline the general features of fungi?
- unicellular or multicellular
- nucelus and other membrane bound organelles - cell wall composed of chitin
- no chloroplast or chlorophyll
- have a body or mycelium
- nutrients acquired mainly by absorption of decaying material (saprophytic feeders)
- most store their food as glycogen
Examples include mushrooms, mould and yeast
Outline the general features of plantae?
- multicellular
- a nucleus and other membrane bound organelles (chloroplast and cell wall composed of cellulose)
- most do not move
- nutrients are acquired by photosynthesis - autotrophic feeders
- store food as starch
Outline the general features of animialia?
- multicellular
- nucleus and other membrane bound organelles (no cell walls or chloroplast)
- move with aid of cilia, flagella or contractile proteins
- nutrients acquired by ingestion (heterotrophic feeders)
- food stored as glycogen
