evolution Flashcards
what did Darwin and Wallas observe?
pattern
hypothesized process
what is pattern?
organisms only live in environments to which they are well adapted
what is hypothesized process?
environmental factors prevent any organism that is not well adapted from successfully reproducing (natural selection)
what is darwins theory of evolution?
variation exists among individuals of a population
variation is heritable
variation affords different traits to individuals
competition exists among individuals
variation provides material for natural selection to act on
an organism suited to its environment is more likely to survive
what is natural selection?
observable way for life to change
how are traits coded for?
by DNA which forms genes on a chromosome
characteristics of sexual reproduction?
offspring inherit genetic material from their parents
results in recombination of genetic material
new combinations in every generation
23 chromosomes for each sperm and egg
characteristics of mutation?
random in DNA
arise and can spread through a population
provide genetic variation which leads to evolution
small changes are good, large changes are harmful
types of mutations?
deletions
duplications
inversions
what is a deletion mutation?
DNA pair is removed from the strand
what is a duplication mutation?
DNA is repeated
what is an inversion mutation?
DNA bases are reversed in order
what does fitness refer to?
probability of successful reproduction
ability to survive
find a mate
produce viable offspring
what happens when the environment changes?
the traits that are beneficial also change
what does natural selection affect?
the individual