SURE A+
✔✔What are species concepts? Example? - ✔✔Definitions to distinguish species with
-ex: Biological SC
*defined by reproductive isolation (inability to interbreed in nature), prevents gene flow
✔✔What is speciation? - ✔✔the formation of a new species
✔✔What are the 2 mechanisms for speciation? - ✔✔*both defined by the initial type of
barrier to gene flow (interbreeding) between 2 populations
1) Allopatric Speciation
-initial barrier is geographic
2) Sympatric Speciation
-initial barrier is biological (i.e. sexual preference)
✔✔What must be true for the evolution of complex structures? - ✔✔every step must be
more adaptive
✔✔What are two processes that contribute to evolution of complex structures? - ✔✔1)
Gradual Improvement
-incremental changes to simple structures with the same function
2) Exaption
-converting older adaptations to new uses
✔✔What are the 5 probable steps in the formation of the 1st cells? - ✔✔1) Abiotic
synthesis & accumulation of organic compounds (monomer building blocks)
-from rxns in atmosphere, volcanoes, space, & ocean hydrothermal vents
2) Abiotic formation of polymers
3) Enclosure in lipid bilayer (made of fatty acids)- protocells formed
4) Simple RNA-based genetic & metabolic systems self organize to create "RNA world"
-DNA & proteins appear later
5) Appearance of controlled reproduction defines first cell
✔✔Early Earth History Events (in order) - ✔✔-origin of Earth
-formation of Earth's crust & atmosphere
-chemical evolution
-1st cells appear
-metabolic evolution
-1st eukaryotic cells
-multicellular eukaryotes
✔✔What were the 1st cells like? - ✔✔-anaerobic, autotrophic prokaryotes
-left chemical signatures & fossilized structures called stromatolites