Exercise 3B Flashcards
what is phylogeny?
a hypothesis of evolutionary relationship among organisms being studied
what are occipital condyles?
the number and position of condyles is functionally related to an animal’s ability to move its head
what is a gizzard?
a muscular portion of the stomach
the muscle action along with the tough lining of cuticle as well as grit that is ingested, aid in the grinding of fibrous foods such as seeds
what is a urogenital system?
the bladder was a new structure evolved in the tetra pods in which urine is stored before being excreted
urine storage is beneficial on land for sanitary reason and in water conservation
a swim bladder is not a urinary bladder
nitrogenous waste
land vertebrates convert ammonia to urea or uric acid before excretion
what are the two types of metabolisms?
ectothermy - body temperatures is dependent on external environment
endothermy - body temperature is controlled either internally by metabolic processes
reproductive system
amniotic egg: does the egg have extra embryonic membranes? (ex. amniote)
what is ankylosed?
when the quadrate bone is fused in an immovable articulation with the squamate and/or quadratojugal bones
mammals and birds have fused quadrate bones
what are synapomorphies?
shared, derived traits
a synapomorphic character state is a trait that is ancestral and inferred to have been present in their most distant common ancestor
traits of amphibians
occipital condyles: 2 digits on hind limbs: 5 gizzard: no bladder: yes nitrogenous waste: urea metabolism: ecto amnion: no hemipenis: no quadrate fusion: yes temporal holes: 0
traits of mammals
occipital condyles: 2 digits on hind limbs: 5 gizzard: no bladder: yes nitrogenous waste: urea metabolism: endo amnion: yes hemipenis: no quadrate fusion: yes temporal holes: 1
traits of birds
occipital condyles: 1 digits on hind limbs: 4 gizzard: yes bladder: no nitrogenous waste: uric acid metabolism: endo amnion: yes hemipenis: no quadrate fusion: yes temporal holes: 2
traits of lizards
occipital condyles: 1 digits on hind limbs: 5 gizzard: no bladder: no nitrogenous waste: uric acid metabolism: ecto amnion: yes hemipenis: yes quadrate fusion: no temporal holes: 2
traits of snakes
occipital condyles: 1 digits on hind limbs: 0 gizzard: no bladder: no nitrogenous waste: uric acid metabolism: ecto amnion: yes hemipenis: yes quadrate fusion: no temporal holes: 2
traits of land turtle
occipital condyles: 1 digits on hind limbs: 2 gizzard: no bladder: no nitrogenous waste: uric acid metabolism: ecto amnion: yes hemipenis: no quadrate fusion: yes temporal holes: 0
traits of alligator
occipital condyles: 1 digits on hind limbs: 4 gizzard: yes bladder: no nitrogenous waste: uric acid metabolism: ecto amnion: yes hemipenis: no quadrate fusion: yes temporal holes: 2
what’s a symplesiomoprhy?
a shared ancestral character state
an ancestral trait shared by 2 or more taxa
every synapomorphy is a symplesiomoprhy. why?
a node represents a synapomorphy and the distant nodes from branches represent symplesiomorphy
what does a * on a cladogram represent?
homoplazy
the trait evolved twice separately
convergent evolution
what is the CI?
consistency index: one measure of the relative amount of homoplasy in a tree
1 means the tree has no homoplasy and all characters are homologies
a CI of .7 means that 70% of the data are good representation of the defined resolution and 30% is not a good representations
how do you calculate CI?
CI is calculated by dividing the total number of character changes possible for a tree by the actual observed number of character changes
CI = E(n-1)/character state changes
character stage change = tick mark
n = # of character states (so when you’re coding and you have 0, 1, 2 –> you have 3 character states and n-1 is 2)
what is a sister group?
groups that separate from a node
