Transcript adaptive radiation - Warren County Public Schools

Patterns of Evolution
Macroevolution/Microevolution
 Macroevolution-
One genus or family
evolves into another….due to large
scale changes that take place over
long periods of time.
 Microevolution- Small scale changes
within a species to produce new
varieties or species in a relatively
short amount of time.
Macroevolution/Microevolution
Both involve changes in allele frequencies
in gene pools
 Both work through the same basic
processes
 The difference is largely one of approach
and scale
 Each offers different insights into the
evolution process

Macroevolution/Microevolution
Macroevolution
Microevolution
1. Large-scale changes
in gene frequencies
2. Occurs over a longer
(geological) time
period
3. Occurs at or above
the level of species in
separated gene pools
4. Consists of extended
microevolution
1. Small-scale changes
in gene frequencies
2. Occurs over a few
generations
3. Occurs within a
species or population
in same gene pool
4. Refers to smaller
evolutionary changes
Macroevolution/Microevolution
Macroevolution
Microevolution
5. Has not been
directly observed
6. Evidence based on
remnants of the past
7. More controversial
8. Example: Birds from
reptiles
5. Observable
6. Evidence produced
by experimentation
7. Less controversial
8. Example: Bacterial
resistance to
antibiotics
Macroevolution/Microevolution
Macroevolution/Microevolution

Dog Variability When bred
for certain traits, dogs
become different and
distinctive. This is a common
example of microevolution—
changes in size, shape, and
color—or minor genetic
alterations. It is not
macroevolution: an upward,
beneficial increase in
complexity.
Patterns of Macroevolution
These are theories/models of evolution
A.
B.
C.
D.
E.
F.
Mass Extinctions
Adaptive Radiation
Convergent Evolution
Coevolution
Gradualism
Punctuated Equilibrium
Mass Extinctions
Event in which many types of living things
became extinct at the same time.
 Period in which huge numbers of species
disappeared.
 Whole ecosystems were wiped out
 Left habitats/niches open
 Resulted in burst of evolution of new
species in new habitat
 Disrupted energy flow throughout the
biosphere and caused food webs to
collapse

Mass Extinctions
 Possible
–
–
–
–
causes
Asteroids hitting earth
Volcanic eruptions
Continental drift
Sea levels changing
Mass
Extinctions
 Is
an on-going
process
Adaptive Radiation
The evolution of an ancestral species,
which was adapted to a particular way of
life, into many diverse species, each
adapted to a different habitat
 Many new species diversify from a
common ancestor .
 The branching out of a population through
variation.
 The new species live in different ways
than the original species did.

Adaptive Radiation
Adaptive Radiation
Convergent Evolution



Opposite of divergent evolution (adaptive
radiation)
Unrelated organisms independently evolve
similarities when adapting to similar
environments, or ecological niches
Analogous structures are a result of this process
Convergent Evolution
Similar body
shapes and
structures
have evolved
in the North
American
cacti...and in
the
euphorbias
in Southern
Africa
Coevolution




The mutual evolutionary influence between two
species
When two species evolve in response to
changes in each other
They are closely connected to one another by
ecological interactions (have a symbiotic
relationship) including:
– Predator/prey
– Parasite/host
– Plant/pollinator
Each party exerts selective pressures on the
other, thereby affecting each others' evolution
Coevolution
Coevolution
Bumblebees and the flowers the they pollinate
have co-evolved so that both have become
dependent on each other for survival.
Coevolution
Praying Mantis simulates plant to protect itself
from predators and eats pests that are attracted
to and feed on the plant, so it protects the plant.
Coevolution
Shrimp cleaning
Titan triggerfish
in Pacific Ocean