Classification 🦋 Flashcards
Define classification:
process by which living organism sorted into groups.
Share similar anatomical features
Define taxonomic group:
Hierarchy of most general groups to most specific:
Domain (most recent)
Kingdom
Phylum
Class
Order
Family
Genus
Species
Hierarchical classification referred to as Linnaean classification.
Why do scientists classify organisms?
Identify species
Predict characteristics
Find evolutionary links (common ancestor)
Created to observe organisms
How are organisms classified?
Separates organisms into 3 domains:
Archaea, Bacteria, Eukarya
Organisms in each group become more similar = share more same characteristics.
Define species:
Group of organisms that are able to reproduce to produce fertile offspring.
What does the term binomial nomenclature refer to?
Universally accepted way or naming organisms
Specify genus of organism
1st name = genus (generic name)
2nd name = species (specific name)
Presented in italics/ underline
What are the 5 kingdoms?
Prokaryotae (bacteria)
Protoctista (unicellular
eurkaryotes)
Fungi (yeasts, moulds, mushrooms)
Plantae
Animalia
State general features of Prokaryotae:
Unicellular
No nucleus/membrane-bound organelles
Small ribosomes
No visible feeding mechanism –> nutrients absorbed through cell wall
State general features of Protoctista:
(mainly) unicellular
Nucleus + other membrane-bound organelles
some have chloroplast
some are sessile (immobile) or move by cilia/flagella/amoeboid mechanisms.
Nutrients acquired by ingestion of other organisms (heterotrophic feeders) or photosynthesis (autotrophic feeders)
State general features of fungi:
Unicellular or multicellular
Nucleus + other membrane-bound organelles –> cell wall mainly composed of chitin.
No chloroplast/chlorophyll
No mechanisms for locomotion (movement)
body/mycelium made from threads/hyphae
Nutrients acquired by absorption –> decaying material
Saprophytic feeders
Most store their food as glycogen
State general features of plants:
250000 species!
Multicellular
Nucleus + other membrane-bound organelles (chloroplast/cellulose cell wall)
contains chlorophyll
Nutrients acquired by photosynthesis –> autotrophic feeders (make own food)
Store food as starch
State general features of animalia:
Multicellular
Nucleus + other membrane-bound organelles
No chloroplast
Move via cilia/flagella/contractile proteins
Nutrients acquired by ingestion (heterotrophic feeders)
Food stored as glycogen
What are the recent changes to the classification system?
Study of genetics + other biological molecules –> scientist can study evolutionary relationships between organisms
use links to classify organisms
How can we use DNA to compare organisms?
Organisms evolve = internal + external features change
DNA determines proteins which determines characteristics
If characteristics change –> DNA changed
Comparing DNA = study evolutionary relationships
How does haemoglobin differ in organisms?
Haemoglobin = 4 polypeptide chains –> fixed number of AA
Difference between chimps + humans = 1 AA
indicates common ancestor in primate groups.
What does the three domain system by Carl Woese propose?
Domain = top of hierarchy
Woese’s system groups organisms using differences in sequences of:
~> nucleotides in cells’ ribosomal
RNA (rRNA)
~> cells’ membrane lipid
structure
~> sensitivity to antibiotics
What are the 3 domains?
Eukarya –> 80s ribosomes
RNA polymerase contains 12 proteins
Archaea –> 70s ribosomes
RNA polymerase of different organisms contains 8-10 proteins
Bacteria –> 70s ribosomes
RNA polymerase = 5 proteins
What is the difference between archaebacteria and eubacteria?
Archaebacteria (ancient bacteria) –> live in extreme environments –> hot thermal cents/high acidic environments
~> no peptidoglycan cell wall
Eubacteria (true bacteria) –> found in all environments
~> peptidoglycan cell wall
