Download Chapter 14-3

Chapter 14-3
- Gene mutations and gene recombinants provide the variations upon which natural
selection is based.
- Natural selection can operate only on the phonetic variation among individuals.
- Sexual Reproduction doesn’t change the relative frequency of alleles in a population,
(Shuffling and reshuffling cards produce a large variety, but not the cards themselves.)
- Now define species as a group of similar organism that breed with one another and
produce fertile offspring in the natural environment.
Chapter 11-4
VOCAB
Speciation = how new species arise from old ones
Niche = an organism’s habitat and its role in that habitat
Reproductive isolation = the separation of populations so that they do not interbreed to
produce fertile offspring
Adaptive radiation = a process where one species gives rise to many species that appear
different externally but are similar internally
Divergent evolution = a pattern of evolution where one species gives rise to many
species that appear different externally but are similar internally
Convergent evolution = a phenomenon where adaptive radiations among different
organisms produce species that are similar in appearance and behavior
Analogous structures = structures that are similar in appearance and function but have
different origins and usually different internal structures
- No two species can occupy the same niche in the same location for a long period of time
(competition, one lives, one dies)
- Reproductive isolation is one of the most common ways in which new species form
when populations are separated.
- Can occur by geological barriers (rivers, mountains, roads) courtship behaviors
- The separate species become better adapted to their environment and the
two different species evolved.
STEP ONE- Found in parents
They survive and reproduce on Island A
STEP TWO- Separation
- Some Island A finches move to Island B and become isolated.
STEP THREE- Changes in gene pool
- Finches become adapted to the needs of the environment
STEP FOUR- Reproductive Isolation
- Isalnd A and B finches will not breed with each other anymore, resulting in
separate species
STEP FIVE- Sharing the Same Island
Chapter 14-5
VOCAB
Genetic drift = a random change in the frequency of a
gene
Gradualism = a theory that evolutionary changes occur slowly
Equilibrium = a state in which no change occurs
Mass extinction = a phenomenon where many species suddenly die off and/or vanish
Punctuated equilibria = a pattern of long stable periods interrupted by brief periods of
change