EEB384H1 Lecture Notes - Lecture 1: Carl Linnaeus, Polyphyly, Paraphyly
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14 Feb 2016
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Carl Linnaeus places reptiles and amphibians together as "Amphibia" in system •
naturea
Cold body: Mainly ectothermic but not generally cold -maintain high body •
temperatures by getting heat from external force (sun)
Some reptiles and amphibians that can generate their own body heat (ex.
Leatherback sea turtles)
Mainly pale: some very brights coloured lizards , tree frogs , diversity of colors •
Cartilaginous skeleton : they have osified skeletons, •
Calculating eye: eye has been lost various times and is less functional in •
amphibian groups
Offensive voice: some do not vocalize •
Linnaeus was wrong to place reptiles and amphibians together in the same
biological group , not only are they distinct groups , they are not each other's
closest relatives
They are both polyphyletic and paraphyletic (break both cardinal rules of modern
phylogenetic taxonomy)
Features that reptiles and amphibians share
Ectothermy- the need to obtain energy from external sources to raise body •
temperatures to levels suitable for normal activity
Leads to similiarities in:
Body size and shape = large bodies require internal heating ‣
Metabolic rate = low rate because energy not expended on heat ‣
generation. Important in ecosystems , they make up a lot of biomass
because all the energy that goes into them the energy devoted to tissue
development and in birds it is heat
Biomass = high biomass because energy goes towards tissue production ‣
rather than temperature maintenance
What makes amphibians unique among tetrapods?
Amniotic egg, sensitive to desiccation •
Skin usually moist, thin, smooth and permeable to water and gases*(* evolution •
More than one clade, doesn't include
common ancestor = poly
Don't include all of the decendants of
recent common ancestors of all the
species in the group =para