Updated RATED A+ | NEW 2026
Biological Evolu on
organisms change over me
Darwin
Theory of Natural Selec on (short necked giraffes die and therefore, don't reproduce)
Lamarck
Inheritance of Acquired Characteris cs (giraffes stretch their necks to reach food and then their
offspring are born with the longer neck)
Evidence of Evolu on
Fossils, Transi onal Forms, Analogous Structures, Homologous Structures, Ves gial Structures
Fossils
hard body parts, embedded in sedimentary rock, deposited in Strata
Mold
air space remains
Cast
Silica fills space
Transi onal Form
Whale: reduced hind limbs and pelvic bones
Analogous Structure
evolved separately but have similar func ons ex. human and octopi eyes
Homologous Structure
similar structure but have different func ons ex. arm, cat, whale, bat
biochemical evidence of evolu on
DNA, ATP, enzymes are universal
, Gene c Code evidence of evolu on
RNA to amino acid triplets are universal, many genes are shared by all organisms
Microevolu on
change in allele frequency in a popula on over me
who evolves
popula ons
Hardy Weinberg Equilibrium
No muta ons, No gene c dri6, No gene flow, No natural selec on, Random Ma ng
Muta on
cause allele frequency in a popula ons, only source of varia on, random events
Gene c Dri6
causes allele frequency to fluctuate; greater in smaller popula ons
Bo9leneck Effect
catastrophe kills large amount of people, loss of gene c diversity; recessive alleles become
more present
Gene Flow
movement of alleles between popula ons; mixes gene c diversity in a popula ons; makes two
pools or more similar popula ons similar
Random Ma ng
individuals do not choose mates, never observed in natural popula on
Natural Selec on
heritable varia on, over-reproduc on causes compe on and differ in reproduc ve success and
fitness, Adapta on
Natural Selec on: Stabilizing Selec on
select against extremes
Natural Selec on: Direc onal selec on
one extreme is favored