2.1 Biodiversity and classification Flashcards
Define classification
The process of naming and organising organisms into groups based on their characteristics and evolutionary history.
Can the classification of an organism change?
Yes, the classification of an organism may change as new information becomes available.
Name the seven groups in the hierarchy of taxons, from largest to smallest.
Kingdom → Phylum → Class → Order
→ Family → Genus → Species
What is the five kingdom classification system?
The classification of organisms into five major kingdoms: Animalia, Fungi, Plantae, Prokaryotae and Protoctista.
What is the three domain classification system?
A method of classification in which organisms are categorised into three groups; Archaea, Bacteria and Eukarya.
How was the three domain system of classification developed?
• By analysing molecular differences between organisms to determine their evolutionary relationships
• Evidence showed that the kingdom ‘prokaryotae’ could be divided into two groups. All other organisms are eukaryotes.
What do organisms in the same domain have in common?
Organisms in the same domain share a distinctive pattern of ribosomal RNA.
What is Bacteria?
• One of the three domains
• Consists of ‘true’ bacteria
• Also known as Eubacteria
What is Archaea?
• One of the three domains
• Made up of primitive bacteria existing in extreme environments, e.g. extremophile prokaryotes
• Also known as Archaebacteria
What is Eukarya?
• One of the three domains
• Consists of all eukaryotic organisms
Outline the features of the kingdom Prokaryotae.
• Unicellular prokaryotes
• Lack a true nucleus and membrane-bound organelles
• Rigid cell wall
Outline the features of the kingdom Plantae.
• Multicellular eukaryotes
• Photoautotrophs
• Cellulose cell walls
Outline the features of the kingdom Animalia.
• Multicellular eukaryotes
• No cell wall
• Heterotrophic
• Nervous coordination
Outline the features of the kingdom Fungi.
• Eukaryotes
• Heterotrophic
• Chitin cell walls
• Grow by producing branching filaments, hyphae
• Asexual reproduction via spores
Outline the features of the kingdom Protoctista.
• Mainly unicellular eukaryotes
• No differentiation into tissues
How are different types of evidence used in classification?
• Observations (e.g. fossils) - organisms grouped based on similar physical characteristics.
• Biochemical methods (e.g. DNA genetic fingerprinting)
What is DNA profiling?
• Method of determining the characteristics of an individual’s DNA
• Percentage of DNA or proteins
shared between species is used to estimate relatedness
State the advantage of using biochemical methods of classification.
Biochemical methods reduce mistakes made from observing physical features alone (due to morphological convergence).
Compare homologous and analogous features.
• Homologous features have evolved from the same structure for different functions. They indicate a common ancestor
• Analogous features are structures that have evolved independently for the same function
Give an example of a homologous feature.
Pentadactyl limb (found in mammals, birds and reptiles).
Give an example of an analogous feature.
The wings of birds and insects.
Define species.
A group of organisms that can interbreed to produce fertile offspring.
What are the two components to a binomial name?
• Generic name - the Genus to which the organism belongs (Capitalise this one!)
• Specific name - the species the organism belongs to
What is the advantage of the binomial naming system?
It is universal; an organism’s binomial name is the same everywhere in the world.
