lecture 2 and maybe 3

lecture 2 and maybe 3 - Carolus Linneus develop our current...

Info iconThis preview shows pages 1–2. Sign up to view the full content.

View Full Document Right Arrow Icon
Carolus Linneus develop our current system of classification, which is based on morphology. -- hierarchical system of classification --binomial nomenclature -- Kingdom--- Phylum----- Class---- Order---Family- Genus - Species -- more then 30 taxonomic characters are now recognized -- know names of animals, phylums, class, genus and species -- phylogeny takes a group of animals and attempts to relate them to other animals, either living or extinct. -- history of species development -- characters , features are used to construct phylogeny. - derived characters: new features Homology : character similarity due to common ancestry, most common recent ancestor has same feature Homoplasy: character similarity not due to common ancestry, i.e. the convergence of fusiform shape in aquatic animals i.e. due to external influence, environment -- many animals that are not evolutionary related have developed a fusiform shape b/c it is better adapted for swimming -- fusiform (torpedo, bullet type shape) - best shape for water movement -- most recent common ancestor of dolphin and penguin did not have this shape, -- convergent evolution : acquisition of same biological trait in unrelated species -- divergent evolution : the opposite of convergent, related species evolve different traits Cladistics : evaluation of information for tree building and classification -- allows to construct cladogram (branching diagram that shows how related organisms are and often gives the chronological order of character development) -- dichotomies: 2 way branch, each branch represents divergence of species, also has common ancestor. clad: group of organisms that share derived characters, feature that's not in ancestor Polarity: ancestral/descendant relationships among different character states -- Outgroup: amphioxous (chordate) that does not have vertebrate column -- used to compare to ingroup (all the vertebrates) -- fish, frog. .. -- A character state that separates out-group from in-group is the presence of vertebrate column - Vertebrate Clad: all animals have vertebrate column -- within vertebrate clad, there's tetrapod clad (that has limbs) and this clad excludes fishes -- vertebrate clad--- tetrapod clad-- amniotic clad-- hair (monkey) -- The top animal has all the characters present in lower clads + one unique character -- nested hierarchy of clads allows you to see chronological development of characters Synapomorphy: vertebrate column in synapomoprhic to fish, frog, lizard and monkey
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 2
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 04/06/2012 for the course BIOL biol 2030 taught by Professor Donni during the Winter '12 term at York University.

Page1 / 5

lecture 2 and maybe 3 - Carolus Linneus develop our current...

This preview shows document pages 1 - 2. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online