Variation and Classification - Phylogeny and Classification Flashcards
what is a species
- a group of organisms, very similar in appearance, anatomy, physiology, biochemistry and genetics
- members of a species can breed together to produce fertile offspring
what is phylogeny
the study of evolutionary relationships between species
it shows how closely related different species are
how can the relationships between species be clearly displayed
on a phylogenetic tree (cladogram)
what does two species being closer to one another on a cladogram represent
they are more closely related
what does the point at which two lines diverge away from each other on a cladogram represent
represents a shared common ancestor, which is now extinct
what is convergent evolution
- the evolution of similar features in distantly related species
- convergent evolution creates analogous structures that have similar form of function but have evolved separately
what is classification
grouping life on earth, using the similarities and differences between organisms to classify them
what does classical “Linnaean” classification rely on
the observable features of an organism
what is the order of taxons
Domain
Kingdom
Phylum
Class
Order
Family
Genus
Species
who first devised the binomial system
Carl Linnaeus
what language is used as a universal language in the binomial system
Latin
why is it important that the binomial name is universal
- organisms can have more than one “local” name
- an organism can be referred to as different things in different parts of the world
- a “local” name can refer to a wide range of different organisms
- translation of languages or dialects may have different names
what are the conventions to follow when using binomial names
- genus always begins with capital letter
- species always begins with a lower case letter
- if typing must be in italics
- if handwritten must be underlined
what information is needed to classify an organism
- geographical location
- embryological, anatomical, physiological and developmental
- biochemical molecular analysis
- knowing whether they can interbreed with other populations
what does modern classification rely heavily on
molecular evidence
give two examples of molecular evidence
- cytochrome c
- DNA/RNA
what is cytochrome c
all organisms that respire must have cytochrome c, but the protein is not the same in all species
how can cytochrome c be used to help classify organisms
- by comparing the amino acid sequence scientists can conclude how related two species are, based on the similarities between sequences
- the greater the number of differences between two sequences, the greater the evolutionary distance between two species
how can DNA/RNA be used to help classify organisms
- analysing DNA sequences and looking for differences is a way of telling how evolutionary distant they are from each other
- the more similarities in the code of two species, the more closely related they are
what evidence is used to classify organisms
- fossil record
- embryology
- anatomical
