Download Lecture Chpt. 24 Evolutn Show 5 Origin Species

Mom, Dad…
There’s something
you need to know…
I’m a MAMMAL!
Origin of Species
Chpt. 24
“That mystery of mysteries…”
Darwin never actually tackled
how new species arose…
Both in space and time,
we seem to be brought
somewhat near to that great fact
—that mystery of mysteries—
the first appearance of
new beings on this Earth.
Macroevolution
macroevoluti
macroevolu
macroevo
speciation
speciati
specia
spec
speciation - origin of a new species
KEY TO MACROEVOLUTION!!
Anagenesis = one
species
transforming
into one other
species
No biological
diversity
created
speciation = origin of a new species
Cladogenesis =
one species
transforming
into more
species
Biological
diversity
created
speciation = origin of a new species
potential to interbreed
produce viable offspring
So…what is a species?

Biological species concept



defined by Ernst Mayr
population whose members can
interbreed & produce viable,
fertile offspring
reproductively compatible
Distinct species:
songs & behaviors are different
enough to prevent interbreeding
Eastern Meadowlark Western Meadowlark
Question
How many species of African
Violets are here?
What
factors/
barriers
can
isolate
gene
pools?
mixing
What
factors
isolate
gene
pools?
What
factors
isolate
gene
pools?
What
factors
isolate
gene
pools?
Habitat
Isolation
allopatric

geographic separation
What
factors
isolate
gene
pools?
Temporal
Isolation
Temporal isolation

Species that breed during different times of day,
different seasons, or different years cannot mix
gametes
sympatric

reproductive
separation
Eastern spotted skunk
(L) & western spotted
skunk (R) overlap in
range but eastern mates
in late winter & western
mates in late summer
What
factors
isolate
gene
pools?
Behavioral
Isolation
Blue footed boobies mate
only after a courtship display
unique to their species
reproductive isolation
What
factors
isolate
gene
pools?
Behavioral
Isolation
QuickTime™ and a
decompressor
are needed to see this picture.
reproductive isolation
What
factors
isolate
gene
pools?
Mechanical
Isolation
sympatric speciation?
Even in closely related
species of plants, the
flowers often have distinct
appearances that attract
different pollinators.
These 2 species of monkey
flower differ greatly in
shape & color, therefore
cross-pollination does not
happen.
Plants
What Animals
factors
isolate
For many insects, male &
gene
female sex organs of
closely related species do
fit together, preventing
pools? not
sperm transfer
sympatric speciation?
QuickTime™ and a
decompressor

are needed to see this picture.
Mechanical
Isolation

lack of “fit” between sexual organs:
hard to imagine for us… but a big issue for
insects with different shaped genitals!
What
factors
isolate
gene
pools?
Gametic
Isolation
sympatric speciation
Gametic isolation

Sperm of one species may not be able to fertilize
eggs of another species

mechanisms
 biochemical barrier so sperm cannot penetrate egg
 receptor recognition: lock & key between egg &
sperm
 chemical incompatibility
 sperm cannot survive in female reproductive tract
Sea urchins release sperm
& eggs into surrounding
waters where they fuse &
form zygotes. Gametes of
different species— red &
purple —are unable to fuse.
QuickTime™ and a
TIFF (Uncompressed) decompressor
are needed to see this picture.
What
factors
isolate
gene
pools?
Reduced Hybrid
Viability
What
factors
isolate
gene
pools?
Reduced Hybrid
ex. mules
Fertility
Reduced hybrid fertility

Even if hybrids are vigorous
they may be sterile

chromosomes of parents may differ in number or
structure & meiosis in hybrids may fail to produce
normal gametes
Mules are vigorous,
but sterile
Horses have 64
chromosomes
(32 pairs)
Donkeys have 62
chromosomes
Mules have 63 chromosomes! (31 pairs)
What
factors
isolate
gene
pools?
Hybrid F1 fine, subsequent… no good
breakdown
Hybrid breakdown

sympatric speciation?
Hybrids may be fertile & viable in first
generation, but when they mate offspring
are feeble or sterile
In strains of cultivated rice,
hybrids are vigorous but
plants in next generation are
small & sterile.
On path to separate species.
=Allopatric
Speciation
ex. Adaptive
radiation
ex. Adaptive
radiation
ex. Adaptive
radiation
ex. Adaptive
radiation
ex. Adaptive
radiation
ex. Adaptive
radiation
ex. Adaptive
radiation
Polyploidy
2N
TEMPO
4N
of
evolutio
n
=Sympatric Speciation
Polyploidy
2N
BIG changes
occur
b/c
of
4N
the
accumulatio
n of small
changes
=Sympatric Speciation
GRADUALISM
Polyploidy
TEMPO
2N
of
evolutio
n
4N
=Sympatric Speciation
Polyploidy
Big changes
2N
as it “buds”
from parent
species, few
changes after
that
4N
=Sympatric
Speciation
Stephen J. Gould
how did we
differentiate
????????
change in rate &
timing of
developmental
events in various
parts of the body
how did we
differentiate
????????
If these genes are altered, the
timing of development and rate
will be altered within the species
change in rate &
timing of
developmental
events in various
parts of the body
change in rate &
timing of
developmental
events in various
parts of the body
how did we
differentiate
????????
If these genes are altered, the
timing of development and rate
will be altered within the species
QuickTime™ and a
TIFF (Uncompressed) decompressor
are needed to see this picture.
Clusters of
genes,
involved in the
regulation of
development of
animals,
1983 -Dr. Thomas Kaufman Indiana University
discovered
QuickTime™ and a
TIFF (Uncompressed) decompressor
are needed to see this picture.
QuickTime™ and a
TIFF (Uncompressed) decompressor
are needed to see this picture.
Evolved in the
paleozoic era
If mutated…
OOPS
QuickTime™ and a
TIFF (Uncompressed) decompressor
are needed to see this picture.
antennapedia, a
mutation of the Hox
Gene that turns the
antenna of a fly into
a leg.
Clusters of
genes, that
determine where
limbs and other
body segments
will grow in a
developing fetus
When these genes are
altered, positioning varies
Clusters of
genes, provide
positional info
in the embryo
When these genes are
altered, positioning varies
Clusters of
genes, provide
positional info
in the embryo
So, if we
are
connected,
how did
we
different
iate ???
Evolution is not the
survival of the fittest.
Rather it is the
survival of the just
good enough.
What drove Human Evolution?
QuickTime™ and a
decompressor
are needed to see this picture.
http://www.npr.org/templates/story/story.php?storyId=124906102
Summary
Be able to discuss the
main theories of what is a
“species”.
 Know various reproductive
barriers and examples.

Summary
Know allopatric and
sympatric speciation.
 Be able to discuss
gradualism and
punctuated equilibrium
theories.

Summary
Recognize various ideas
about the origin of
evolutionary novelties.