Transcript Adaptive Radiation

Evolution
Adaptive Radiation
Adaptive Radiation
• The speciation
and adaptation of
an array of
species
• Species show
different
morphological
and physiological
traits
Galapagos
Darwin’s Finches
• Darwin noticed varieties of finches on the
Galapagos
• Kept specimens, but didn’t record which
islands they came from
• Back in England, recognized they were closely
related, but different species
• Finches evolved from an ancestor that came
from mainland S.America
Darwin’s Finches
Convergent and Divergent
Evolution
Convergent
• Pattern of evolution in
which similar traits arise
because different species
have independently
adapted to similar
conditions
Divergent
• Pattern of evolution in
which species that were
once similar to an ancestral
species diverge, or become
more distinct
Convergent
Divergent
Mass Extinctions
Mass Extinctions
• Large scale dying out of a large percentage of
all living organisms in an area over a relatively
short period of time
• There have been 5 global mass extinctions
The Big 5
Era
Time
Extinction
Cause
Cretaceous
– Tertiary
65.5 Ma
50% of all Genera, 75% of all species
Dinos killed off, mammals and bird
evolved as dominant
Asteroid or Comet, volcanic
events
TriassicJurassic
205 Ma
48% of all Genera
Large amphibians, other non-dinos
Dinos evolved as dominant (no
competition)
Small impacts, gradual
climate change, massive
volcanic eruptions
PermianTriassic
251 Ma
83% of all Genera
Many insects killed off,
Archosaurs become dominant
Mother of all mass extinctions
Impact?
Volcanism, climate change,
Combination?
Late
Devonian
360-375
Ma
50% of all Genera
Many causes, ocean
anoxia, global cooling
caused by ocean volcanism
57% of all Genera
Many invertebrates extinct
Movement of Gondwana
Ordovician- 440-450
Silurian
Ma
Co-evolution
Coevolution
• The change of a species triggered by the
change of a related object