Module 4 Classification and evolution essential notes Flashcards
Describe biological classification
- Classification is the grouping of items based their characteristics
- Biological classification is the categorisation of organisms
- Based on their biological features
- Including anatomy, physiology, biochemistry and genetics
- Into groups of similar species called taxonomic groups
State the purposes of biological classification
- Identification of species/unknown/newly discovered organisms
- Characteristics of species in taxonomic groups can be predicted based on similarities
- To determine evolutionary relationships between species (phylogeny)
State the order of the taxonomic groups
- Domain
- Kingdom
- Phylum
- Class
- Order
- family
- Genus
- species
Describe the three domains in biological classification
- There are three domains
- One domain that contains all the Eukaryotes (Eukarya)
- And two prokaryotic domains
- These are called the Archaea and Bacteria
Describe the disadvantages of the using common names for organisms
- Organisms may have more than one common name (including different languages internationally)
- Different species may have the same common name
- No information of the relatedness of organisms
Describe the key features of the binomial naming system
- The first part of the name is the genus of the organism
- The second part of the name is the species
- No two species can have both the genus and species the same
- The genus should have the first letter capitalised
- The species should be all in lower case
- When hand-written, both parts of the name should be underlined
State the names of the five kingdoms
- Prokaryotae
- Protoctista (eukaryotic)
- Fungi (eukaryotic)
- Plantae (eukaryotic)
- Animalia (eukaryotic)
State the key identifying features of the prokaryotae kingdom
- Unicellular
- Circular ‘naked’ DNA in cytoplasm
- No membrane-bound organelles
- Smaller ribosomes
State the key identifying features of the protoctista kingdom
- Eukaryotic
- Unicellular
- Contains membrane-bound organelles
- Can have chloroplasts (autotrophic)
- Absence of cell wall
- Can be motile
State the key identifying features of the fungi kingdom
- Unicellular or multicellular
- Eukaryotic
- Contain membrane-bound organelles
- Cell wall present BUT made of Chitin (polysaccharide)
- Heterotrophic (no chloroplasts or chlorophyll)
- Non-motile
- Get nutrition by external digestion
- Store glucose as glycogen
State the key identifying features of the plantae kingdom
- Eukaryotic
- Multicellular
- Contain membrane-bound organelles
- Autotrophic
- Carry out photosynthesis (so have chloroplasts)
- Store glucose as starch
State the key identifying features of the animalia kingdom
- Eukaryotic
- Multicellular
- Contain membrane-bound organelles
- No cell wall
- Heterotrophic
- So no chloroplasts
- Cells can be motile (using cytoskeleton or flagella)
- Glucose is stored as glycogen
State the difference between original and modern methods of classification
- Original classification was based only on observable characteristics
- Partly due to limitations of technology
- Modern classification is based on analysis of biological molecules (DNA, RNA, lipids)
- DNA (gene), RNA base sequences can be compared
- Protein structure and amino acid sequences can be compared
- The structure of lipids can be compared
- Organisms can be classified based similarity or difference on the above features
State the key features of the three domains

State the similarities between the domain and kingdom classification systems
- Eukaryotic organisms are still separated from prokaryotic organisms
- Both still have the four eukaryotic kingdoms (protoctista, fungi, plantae and animalia)
- Both demonstrate the evolutionary relationships
- Both have the taxons with the largest number of species at the top, and ending with taxons with single species at the bottom
State the differences between the domain and kingdom classification systems
- The domain system has more levels of taxons than the kingdom systems
- The top level in the domain systems has a much greater number of organisms than the top level in the kingdoms system
- The domain system separates prokaryotes into two types (Bacteria and Archaea), the kingdom system doesn’t
- The domain system is more accurate as it takes into account molecular evidence as well
Describe how phylogeny and classification are related
- Phylogeny is the evolutionary relationship between organisms
- Organisms evolve over time.
- Genetic changes result in the development of particular protein and structural adaptations
- Classification groups organisms based on the similarity of their adaptations
- The classification should therefore reflect the evolutionary history of species
- Organisms which are similar have a more recent common ancestor
- Organisms which are very different have a more distant common ancestor
Describe how to interpret a phylogenetic tree
- The ends of branches represent existing individual species
- The nodes represent common ancestors no longer in existence
- The length of lines represent time
- More similar species are close together (horizontally)
- More similar species have more recent common ancestors
- More distinct species are further apart (horizontally)
- More distinct species have common ancestors further in the past
Describe observations with which Darwin and Wallace came to form the theory of evolution by natural selection
- There is variation within populations of organisms (they are not all the same)
- Populations of organisms have to survive with limited resources, which causes a competition or struggle for survival, in which not all the members of the population survive to reproductive age
- Offspring tend to develop the characteristics of their parents
- (those that do survive, pass on their characteristics for adaptations)
State the types of evidence for evolution
- Paleontology (analysis of fossils)
- Comparative anatomy
- Comparative biochemistry
Describe the key features of paleontology
- Fossils are the preserved remains of organisms where geological conditions have prevented their complete decomposition
- The depth at which fossils are discovered are related to the time since formation (oldest at the bottom, youngest at the top)
- Simpler organisms such as bacteria and algae are found in the oldest rocks, more complex ones nearer the top
- The sequence of fossils the rocks therefore shows their stage of evolution
- Analysis of bones and other structural features can also be used to determine relatedness
- Soft tissues will not be fossilised
Describe the key features of comparative anatomy
- This is the comparison of structural features of organisms
- Usually this involves homologous structures (observable structures common to a number of different organisms, such as limbs)
- These are analysed and compared to determine which organisms may be more closely and more distantly related
Describe the key features of comparative biochemistry
- This is the analysis of biological molecules such as DNA, RNA, protein and lipid
- Adaptations of organisms developed in the evolutionary process are due to genetic changes affecting biological molecules
- The sequences of bases in DNA can be compared
- The sequences of bases in RNA can be compared
- The sequences amino acids in proteins can be compared
- However, the gene/RNA/protein being compared must be present the species being compared
- Fewer differences indicate a more recent common ancestor
State the main types and causes of variation in organisms
- The variation in characteristics between different species is called interspecific variation
- The variation in characteristics within a species is called intraspecific variation
- Variation can be caused by:
- Genetic factors
- And environmental factors