Chapter 24-25 Flashcards
Hybrid
Cross between two species, often produce infertile offspring
Speciation
formulation of two species from one original species
Sympatric Speciation
when members of a population develop a difference without geographic isolation “same homeland”
Allopatric Speciation
when some members of a population leave the area and are separated by a geographic barrier of time (think rivers forming)
Adaptive Radiation
one ancestral species branches into many, each occupying a different NICHE (think lizards)
Reproductive isolation
barriers prevent interbreeding
Temporal isolation
breeding at different times
Habitat isolation
Living in different places
Behavioral isolation
Different mating/courtship behaviors (thing that dancing bird)
Mechanical/Gamete barriers
Different anatomy sizes, sperm/egg problems
Prezygotic Barriers
blocks reproduction from taking place
Post-zygotic Barriers
egg+sperm produce offspring but it doesn’t survive, or the hybrid cant reproduce (LIGER)
Gradualism (speciation)
slow change, small steps
Punctuated Equilibrium
rapid change due to a major environmental disruption
Oparin and Coacervates (1920’s)
GUM ARABIC (CARBS)+GELATIN (PROTEIN)=CONSERVATIVES. Believed first life forms were from an acidic primordial sea, organic molecules became increasingly complex through a series of chemical reactions eventually forming coacervates.
Miller-Urey Model (1953)
Water(Representing Primitive Sea)= Heated-> evaporates into chamber containing methane/ ammonia hydrogen-> sparked to simulate lighting storms-> gas is condensed to liquid
Results:Colorless-> Murky Brown(containing organic molecules and amino acids)
Conclusion: Organic Monomers formed through reactions w/ water and gases-> returned through rain
Sidney Fox and Proteinoids (1960’s)
Mimicked condensation by dripping dilute solutions of organic molecules over hot sand, clay, and rock. Aggregates formed proteinoids (probionts)
