Classification Flashcards
How does Linnaeus’ binomial classifcation system work?
Gives organisms two names: a genus and a specific epithet
What is the classification system in order?
Domain, Kingdom, Phyla, Class, Order, Family, Genus, Species
What can we use to memorise this?
Dear King Phillip Came Over For Good Spaghetti
Systematistic’s approach
Classification should be based on evolutionary relationships, using a phylogenetic tree
Is the Phylogenetic tree limited?
- Usually, unless specified, the tree indicates only pattern of descent.
- Not amount of genetic change or timeline
Homology
Structures that have the same origin but evolved into different adaptions. Such as Human hands vs Cat’s paw
Analogy
Two unrelated structures have evolved to form the same function. Such as Bat wings vs Bird wings vs Insect wings
What is a clade?
- A monophyletic grouping which includes an ancestral species and all of it’s descendants.
- Clades may have distinguishing features
What is a Parsimonious tree?
- A phylogenetic tree that includes the fewest evolutionary changes possible
- Can be deemed most likely to happen when choosing a phylogenetic tree pattern
What is a Orothologus gene?
Homologous genes found in different species as result of speciation. Distantly related species often have many orthologous genes.
What is a Paralogous gene?
Homologous genes within a species that result from gene duplication; genes can diverge and take on new functions. E.g., Humans haemoglobin can take on different roles
What is the molecular clock?
- Some regions of DNA change at a rate constant enough to serve as a “clock”.
- The high amount of genetic change is used to estimate the date of past evolutionary events
- The Molecular clock suggests that the most common form of HIV jumped from primates to humans in early 1900s
Whale case study
- C.S baker and S.R palumbi purchased 13 samples of “whale meat” from a Japanese fish market
- They sequenced part of mtDNA and compared their results to known whale species
- The team contructed a gene tree that shows patterns of relatedness among DNA then among taxa
- Only Minke whales can be sold legally in Japan however, six of the unknown samples were illegal whales
Biological classification
- Based on degree of overall similuatriy between organisms
- Need to be precise, fixed and of universal application
Taxonomy defination
The science of naming and classifying organisms within groups (taxa)
