Module 4.3 - Classification And Evolution Flashcards
Why do we classify organisms?
For convenience for more manageable study of organisms
To make it easier to identify organisms
To help see relationships between organisms
List the 8 taxonomic groups used for classification
Domains Kingdom Phylum Class Order Family Genus Species
Why do classification systems change over time?
Scientific knowledge changes as new discoveries are made
Technological developments lead to new discoveries (e.g. microscopes, new DNA technology)
Differences of opinion amongst biologists/scientists
Why is the binomial name given in Latin?
It acts as a universal language so everyone in the world can use and understand it
Limitations of common names
Same species can have a different common name in another place
Different common names in different languages
Same common name could be used for a different species in another place
Define classification
Process of sorting living things into groups of similar organisms
Reflects how closely related they are and evolutionary relationships
Define taxonomy
Study of principles behind classification
Study of the differences between species (physical and genetic)
Define phylogeny
Study of the evolutionary relationships between organisms
Study of how closely related they are
Name the 5 kingdoms
Animals Plants Fungi Protoctista Prokaryotes
Characteristics of animal kingdom
Eukaryotes Multicellular Heterotrophic feeders No cell walls Fertilised eggs develop into blastula Move freely
Characteristics of plant kingdom
Eukaryotes Multicellular Autotrophic nutrition Cellulose cell walls Fertilised eggs develop into multicellular embryos Contain chlorophyll
Characteristics of fungus kingdom
Eukaryotes Most multicellular (yeast unicellular) Saprophytic feeders Chitin cell walls Reproduce with spores Multinucleate cytoplasm Have a mycelium made up of hyphae
Characteristics of Protoctist kingdom
Eukaryotes Mostly unicellular Autotrophic or heterotrophic feeders Variety of different forms Do not fit into any other kingdom, display features of multiple kingdoms
Character is of prokaryote kingdom
Prokaryotes (no nucleus, loop of naked DNA, no histones) No membrane bound organelles Ribosomes smaller than 70S Smaller than eukaryotes May be free living or parasitic
Define heterotrophic feeders
Eat and digest other organisms
Define autotrophic feeders
Use photosynthesis to make their own food
Define saprotrophic feeders
Digest other organisms outside the body using enzymes
Explain why the appearance and anatomy of Fungi made their classification difficult for early taxonomists
Don’t move freely (like plants)
Hyphae resemble roots
Digest food rather than photosynthesising (like animals)
What were early classification systems based on?
Appearance
Anatomy
Limitations of early classification systems
Easy to make mistakes
Easy to place relatively distance species in the same groups
How is biochemistry used in modern classification?
Cytochrome C is a protein used in respiration so almost every living organism has it
The primary structure of cytochrome C varies from species to species
If primary structure is the same - closely related
If primary structure is different - less related
How are genetics used in modern classification?
The genetic code (order of bases in DNA) is universal so a sequence in one gene in one organism codes for the same protein in any organism
Compare DNA of different species
More similar genetic code means more closely related and visa versa
Name the 3 domains
Eubacteria
Archaebacteria
Eukaryotae
How was the 3 domain system developed?
Studying RNA
