Classification / Phylogeny Flashcards
(18 cards)
Why do scientists classify species?
- convenience
- species identification
- to find evolutionary links
- organisation of information
Define taxonomy:
The practice of naming and classifying species and groups of species within the hierarchal classification scheme.
What are the taxonomic ranks?
Domain, Kingdom, Phylum, Class, Order, Family, Genus, Species
Why are binomial names more useful for classification than common names?
- same organisms may have completely different common names across the world
- translations / dialects may give different common names
Define binomial system:
Species has a generic name (genus) and a specific description (species)
e.g. Varanus komodoensis
- generic name is capitalised, specific description is not.
What are the 5 kingdoms?
- Prokaryotae
- Protoctista
- Fungi
- Plantae
- Animalia
What are the different types of feeding mechanisms?
Autotrophic = photosynthesises
Heterotrophic = ingests other organisms
Saprophytic = nutrients from absorption
Describe Prokayotae:
- unicellular
- no visible feeding mechanisms - nutrients absorbed through cell wall or photosynthesised
- rings of DNA, small ribosomes
- no nucleus / membrane bound organelles
e.g. E coli, S aureus (bacteria)
Describe Protoctista:
- mainly unicellular
- nucleus & membrane bound organelles - some contain chloroplasts
- some are sessile, others move by cilia / flagella
- heterotrophic / autotrophic / both
e.g. Amoeba, Paramecium
Describe Fungi:
- uni OR multicellular
- nucleus & membrane bound organelles - no chloroplasts
- chitin cell wall
- food stored as glycogen
- no locomotive mechanisms
- saprophytic / parasitic
e.g. Mushrooms, Mould, Yeast
Describe Plantae:
- multicellular
- nucleus & membrane bound organelles & chlorophyll
- cellulose cell wall
- do not move - some gametes move via cilia / flagella
- food stored as starch
- autotrophic
Describe Animalia:
- multicellular
- nucleus & membrane bound organelles - no chloroplasts
- move via cilia / flagella / contractile proteins
- food stored as glycogen
- heterotrophic
What are the three domains?
- Eukarya
- Bacteria
- Archaea
Why is archaea more closely related to eukarya than bacteria?
- similar enzymes for RNA synthesis (RNA polymerase)
- similar mechanisms for DNA replication and RNA synthesis
- different cell wall / plasma membrane structure
- production of some proteins that bind to DNA
How is bacteria different to archaea?
- cell wall is peptidoglycan
- different enzymes for RNA synthesis
- different mechanisms for DNA replication / RNA synthesis
- proteins are not bound to genetic material
What is meant by phylogeny?
The evolutionary relationships between organisms - phylogenetics refers to the study of the evolutionary history between groups of organisms.
What are the advantages os using phylogenetic classification?
- produces a continuous tree - traditional classification requires discrete taxonomic groups. Phylogenetic trees can be added to.
- Linnaean classification system assumes all groups within each taxonomic rank are equivalent, even though they have evolved at different times and have varying levels of species diversity.
