2 Macroevolution - The One Tree Of Life Flashcards
Everything originates from…
Single common point (origin)
(Carl Linnaeus - latin nomenclature naming system Genus-species)
Biblical interpretation of time
22nd october 4004 BC (earth dates)
4 main geological periods
Phanerzoic - visable life
Cenozoic - mammal dominated
Mesozoic - dinosaur dominated
Paleozoic - pre-dinosaur vertebrates
Principle of faunal succession
repeated changes in fossils present through strata
Index fossils
indicate a particular geological period (biostratigraphy)
Phalenozoic vs Protonozoic
Phalenozoic - visable life (fossils can be found)
Protonozoic - before visable life (no fossils found)
Gideon Mantell
Tilgate Quarry, and Iguanodon and idea of the Mesozoic
Evolution
change over time / the fossil record is consistent with change overtime but without a mechanism that can drive change, interference is weak.
Variation in living forms
within species and in domestication + similarity (and differences) between species
Decent by modification
- Too many individuals survive
- Differential survival between individuals
- Gradual change in traits in population = new species
Artificial selection
can take a species to different phenotypes (breeds) if select individuals of one character type over another for breeding. If this selection occurred naturally it would cause spatial diversification or different species.
Darwin applied gradualism to natural selection
small current differences in fitness between individuals (microevolution) large morphological changes (new species) overtime (macroevolution)
Evidence for a single common origin
Conservation of molecules (all cells contain these molecules) - (DNA / RNA / proteins / amino acid set / glucose based energy source / ATP —> ADP as fuel of cell processes / core biochemicals - eg. Lipids)
Conservation of structures (cells / membranes / lipid bilayers / membrane spanning proteins / ribosomes built from rRNA and ribosomal proteins)
Conservation of processes (core genetic code / DNA —> RNA —> protein transfer of information / metabolism and enzymes that operate it / use of protein modification)
Anthropocentric
regarding human kind as the central or most important element of existence as opposed to God or animals
How do we estimate the tree of life
Anatomy, physiology based and DNA based
Related species have shared, derived traits (homologies)
Problem with convergent evolution
Similar selection pressure in different taxa so same character / same function derived independently - convergent evolution - analogous features
Divergent evolution - different features evolving - homologous (they have 1 common ancestor so it’s the process of 2 species become more distantly related)
DNA provides many 1000s of characters —> overcome convergence
DNA might not always be able to be used as dead creators don’t retain their DNA (decomposition)
Convergent evolution - pentadactyl limb
This would show we are related to reptiles as they also have this feature (pentadactyl limb is a shared feature of all tetrapods) —> however same characteristics can be developed from convergent evolution, same feature but derived independantly
(analogous trait - same feature derived due to similar environmental pressured)
Dating radioisotopes
Recent biological material —> 14Cdecay —> 12C (t50 = 5740years) (known half life of C14 and compare it to how much C12 is there and you can find out what age certain rocks are)
Ancient rock material —> 40K—> 40Ar (t50 = 1,248 x 10^9)
Dating radioisotopes for petrified fossils in sedimentary rock
Geological strata - deposits overtime
Surface - recent
Deep past - buried
Strata from which fossil recoded - age
Molecular clock
DNA sequence divergence may also estimate time from common ancestor
Nucleotide and AA substitutions accumulate as time asses since common anscetory, presumed to occur ar a constant rate for a specific gene - calibrate by known events (fossils)
Why estimate the tree of life
Tells us if particular lifestyles evolved repeatedly and the taxa they evolved out of
Tells us where pathogens emerge from (prevent repeats)
Tells us biological forms (eg. Trees) are analogous / not evolutionary groups
Theistic views of biodiversity - Gap creationism
earth is old but diversity is not
Theistic views of biodiversity - progressive creationism
mutation and selection exist and occasional interventions
