Classification Flashcards
Domain and what are the three domains?
The highest taxonomic rank. Three domains are Archaea, Eubacteria and Eukaryote
What are the five kingdoms?
Plantae, Animalia, Fungi, Protoctista and prokaryote
What are the taxonomic ranks?
Kingdom Phylum Class Order Family Genus Species
What is the biological definition of a species?
A group of organisms that can freely interbreed to produce fertile offspring
What is the phylogenic definition of a species?
A group of individual organisms that are very similar in appearance, anatomy, physiology, biochemistry and genetics
Prokaryote
- have no nucleus
- loop of DNA not in chromosomes
- naked DNA
- no membrane bound organelles
- smaller ribosomes
- smaller cells
- free living or parasitic
Protoctista
- eukaryotic
- mostly single celled
- wide variety of forms
- plant-like or animal-like features
- autotrophic or heterotrophic nutrition
Fungi
- eukaryotic
- exist as single cells or have a mycelium which consists of hyphae
- chitin walls
- multinucleate cytoplasm
- mostly free living and saprophytic
Plantae
- eukaryotic
- multicellular
- cells surrounded by cellulose cell wall
- autotrophic
- contain chlorophyll
Animalia
- eukaryotic
- multicellular
- heterotrophic
- able to move around
What is phylogeny?
The study of evolutionary history of groups of organisms. Explains who is closely related to whom.
Biological molecules used as evidence in classification
DNA and proteins can be compared, the more similar the molecules the more closely related the organisms.
CYTOCHROME C is found in all living organisms as it is needed for respiration. However, it is not the same in everyone. The amino acid sequence of cytochrome c in two organisms can be compared, the more simialr the sequence, the more closely related they are.
DNA base sequence can be compared, more similar the sequence in a part of DNA, the more closely related the species.
Other evidence to show how similar organisms are
EMBRYOLOGICAL - similarities in the early stages of an organisms development
ANATOMICAL - similarities in structure and function of body parts
BEHAVIOURAL - similarities in behaviour and social organisation
How are archaebacteria different from eubacteria?
- different cell membrane structure
- flagella
- different enzymes for synthesising RNA
- no proteins bound to genetic material
- different mechanisms for DNA replication and for synthesising RNA
How are archaea similar to eukaryotes?
- similar enzymes for synthesising RNA
- similar mechanisms for DNA replication and synthesising RNA
- production of some proteins that bind to their DNA