Classification Flashcards
What is taxonomy?
The process of arranging organisms into groups based on shared features
What are the five kingdoms of classification?
- Prokaryotes
- Protoctista
- Fungi
- Plantae
- Animalia
Examples include bacteria, algae, moulds, mosses, and fish
What are the key characteristics of Prokaryotes?
- No nucleus
- Unicellular
- Cell wall made of murein
What are the key characteristics of Protoctista?
- Unicellular
- Simple multicelluar
- Cellulose cell walls
What are the key characteristics of Fungi?
- Chitin cell walls
- Hyphae
- Saprotrophic nutrition
What are the key characteristics of Plantae?
- Multicellular
- Cellulose cell walls
- Autotrophic
What are the key characteristics of Animalia?
- Multicellular
- No cell walls
- Heterotrophic
What are hyphae in fungi?
Branched filaments of cells
How do fungi digest food?
- Secrete enzymes outside the cells to break down large molecules
- Absorb the products into the cells
How do animals digest food?
- Food is ingested through the mouth
- Digested in the gut and absorbed into gut cells
- Undigested material is expelled through the anus
What are the three domains of life?
- Bacteria
- Archaea
- Eukarya
What are the key differences between prokaryotes and eukaryotes?
Prokaryotes:
- No nucleus
- 70S ribosomes
- No membrane-bound organelles
Eukaryotes:
- Have a nucleus
- 80S ribosomes
- Membrane-bound organelles
What are the features of Bacteria?
- Prokaryotic
- Circular DNA
- 70S ribosomes
- Cell wall made of peptidoglycan
- Sensitive to antibiotics
What are the features of Archaea?
- Prokaryotic
- Circular DNA
- 70S ribosomes
- Can grow at extreme temperatures
- Not sensitive to bacterial toxins
What are the features of Eukarya?
- Eukaryotic
- Linear DNA
- 80S ribosomes
- Contains membrane-bound organelles
What is the taxonomic hierarchy?
Domain → Kingdom → Phylum → Class → Order → Family → Genus → Species
Example: Humans are classified as Eukaryote, Animalia, Chordata, Mammalia, Primates, Hominidae, Homo, sapiens.
What is binomial nomenclature?
A universal system for naming organisms with the genus name first (capitalized) and species name second (lowercase).
Written in italics or underlined (e.g., Homo sapiens).
What is phylogeny?
Study of evolutionary relationships between organisms- shown using a phylogenetic tree.
How has DNA sequencing improved classification?
Entire DNA sequences can be compared between species- indicates closer evolutionary relationships
Example: Humans share 94% DNA with chimpanzees.
How are amino acid sequences used in classification?
- Helps determine evolutionary relationships
- More similar sequences suggest closer relationships- common ancestors
How does mutation affect DNA comparisons?
- Mutations cause differences in DNA sequences over time
- More differences indicate less closely related species
