Lecture 11 - Macroevolution Flashcards
What is irreducible complexity?
- a system composed of several parts that all contribute to a function
- removal of any part causes the system to cease functioning
What is the rebuttal to irreducible complexity?
- pieces of complex systems often have functions of their own
- “making a simpler mouse trap”
What is an example of a rebuttal against reducible complexity argument?
- bacterial flagellum (basal body)
- made of parts that could serve other functions
- can function if parts are missing
What is another example against reducible complexity?
-eyes
What does “the evolution of new species is rarely if ever observed” mean as a critique of evolution?
-we never see it happen
What are 2 major rebuttals against the claim that new species are never observed?
- too little of time to observe origin of new species (<0.0066% of biological history)
- we HAVE observed origin of new species
(in lab, polyploidization, naturally without polyploidization)
What is punctuated equilibrium?
- periods of evolutionary stasis interspersed by major change
- (nothing, then sudden change)
punctuated equilibrium is not explained by ___________
Darwinian Theory
What did Darwin’s theory believe in instead of punctuated equilibrium?
gradualism
What are 3 rebuttals to punctuated equilibrium?
- punctuations that appear abrupt in fossil record may take tens of thousands of years
- periods of apparent stasis may fail to give a true impression of biochemical changes not detectable in fossil record
- slight genetic changes may result in phenotypic changes
Sometimes changes at a single ______ can cause _______
gene, speciation
In many cases, what is the origin of large phenotypic changes?
evolution of genes controlling development (evo-devo)
What is heterochrony?
changes in rate and timing
What does heterchrony include?
- changes in relative growth rates of different body parts (allometry)
- changes in timing of reproductive vs. somatic development
What does relatively rapid reproductive growth result in?
paedomorphosis