Download 2 Types of Evolution

Evidence for Evolution on Earth
 Fossil Record – transitional fossils
 Comparative Anatomy – homologous, analogous,
vestigial
 Comparative Embryology
 Comparative Biochemistry
 Geographic Distribution
Evidence From Fossils
 Analogous Structures
 Homologous Structures
Vestigial Structures – some
bird wings; snakes and
whale hips/pelvic girdle
Transitional
Embryological Evidence
Biochemical Differences
Continental drift
 Earth’s continents have moved during Earth’s history
and are still moving today at a rate of about six
centimeters per year.
 The theory for how the continents move is called plate
tectonics.
http://www.youtube.com/watch?v=GYVS_Yh6dTk
 Microevolution
 Small scale
 Macroevolution
 Large scale
To understand this better, you must
know what a species is:
 One group of interbreeding organisms
found in one place at one time.
 Small scale evolution occurring over a relatively short
period of time = changes within one population
 Produces “ecotypes” or ecological races.
 Examples: differences in eastern and western bird species
color, orcas, etc.
 Includes 4 topics
 Mutation
 Selection
 Gene Pool
 Genetic Drift
 Large-scale evolutionary patterns and processes that
occur over long periods of time = speciation (making
a new species)
 Includes 6 topics:
 Extinction
 Adaptive radiation
 Convergent evolution
 Divergent evolution
 Punctuated equilibrium
 Changes in developmental genes
 Darwin believed that
organisms evolved
gradually. (gradualism)
 Niles Eldredge and
Stephen Jay Gould believed
punctuated equilibrium
is how organisms evolved,
periods of rapid evolution
followed by periods of
stasis.
 BOTH REPRESENT
DIVERGENT EVOLUTOIN
 Single species or small groups of species evolved into
diverse forms living in different ways. Can lead to
convergent evolution.
 Adaptive radiation can produce unrelated organisms
that look similar due to similar environments.
 Example: “This butterfly
The process by which
two species evolve in
response to changes in
each other over time.
http://ecology.botany.ufl.edu/ ecologyf02
acquires a cardiac glycoside
from members of the genus
Asclepias. Because of their
milky sap, these are
commonly referred to as
milkweed plants. The plants
produce this toxin as a
defense against herbivory, but
the Monarch has the ability
to sequester the toxin in fatty
tissues so that it makes the
butterfly unpalatable while
not poisoning the butterfly.”
 Also conceptually considered a biological “arms race”
in some instances.
Change by Desire
Change by Acquired Traits
Change by Use/Disuse
 2 Examples:
 Camouflage or Cryptic Coloration
 Mimicry
 Not all traits are adaptations!
 exaptations - Features (such as feathers) that evolved by
selection for one purpose (such as warmth) and were
later adapted to a new purpose (such as flight).
 Four Main Steps
 Variation
 Heritability of the variation
 Overproduction
 Reproductive Advantage due to a
Competitive Advantage
(Adaptation)
1. Do changes occur in
individuals or
populations?
2. Where does competition
for resources fit in?
3. Can you list 5 plant or
animal adaptations?
Contrast with ARTIFICIAL SELECTION
(or selective breeding)
Natural Selection
 Process by which POPULATIONS change in response
to their environment as better adapted individuals
survive and leave more offspring.
 Generally called “survival of the fittest”. It doesn’t say
biggest or strongest; it refers to the FITTEST!
Correct?
 http://www.youtube.com/watch?v=xkwRTIKXaxg
This species of moth gets separated into two distinctly different
forest due to the activity of humans. Draw what the moths might
look like after 10 generations due to the activity of natural
selection.
http://www.google.com/search?rlz=1T4WZ
PG_enUS425US426&q=moth&um=1&ie=U
TF8&tbm=isch&source=og&sa=N&hl=en&tab
 Reproductive Isolation
 Prezygotic = before sex/fertilization
 Behavioral -
 Mechanical  Geographical –
 Temporal -
 Postzygotic = after sex/fertilization
 Sterility -
Which Isolating Mechanism?
Which Isolating Mechanism?
Which Isolating Mechanism?
Which Isolating Mechanism?
Which Isolating Mechanism?
 Stabilizing Selection
 Directional Selection
 Disruptive Selection
 Sexual Selection
 Page 434 – Draw the Graph and provide a summary
AND a new example of each type of selection.