Transcript Vestigial structures

Day 1-Start
Chapter 12
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Let’s make some fossils!!!!- Lab
Day 1- STOP
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Fossils-video
Amber preserves insects
and other organisms from
mineralization.
Petrified wood.
Footprints
Day 2- Start
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A baby mammoth has been uncovered in the permafrost of
north-west Siberia (9,000 years old).
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How does a fossil form?
1. Death
2. Sedimentation
•
Dirt covers it up
3. Permineralization
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Lower layers are
compressed by upper
layers and turned into rock.
4. Uplift
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Former sea floors are lifted
up and become dry land.
5. Erosion
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Rain, wind, earthquakes,
freeze and thaw all work
toward erosion.
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Fossils in lower layers of sedimentary rock
are older. Can be dated on TYPE of fossils.
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Fossil Evidence of Evolution
Fossil
records
document
the course
of life
through
time
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Fossil Evidence of Evolution
Fossil of Archaeopteryx
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Fossil Evidence of Evolution
Evolutionary change in body size and toe
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reduction of horses
Anatomical Evidence for
Evolution
• Homologous structures: structures with
different appearances and functions that all
derived from the same body part in a
common ancestor
• The bones in the forelimb of mammals are
homologous structures
• Different functions, same ancestor
structure
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Anatomical Evidence for
Evolution
Homology of the bones of the forelimb of
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mammals
Day 2- STOP
Complete coloring w/s at this time!!!!
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Day 3- Start
Anatomical Evidence for Evolution
• Vestigial
structures: have
no apparent
function, but
resemble
structures their
ancestors
possessed
Vestigial structures of
a whale
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Vestigial Structures in Humans
Tonsils
Adenoids
Coccyx
Appendix
Little toe
Wisdom teeth
Nipples on males
Pineal gland
Body hair
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Embryological Evidence- developmental
similarities
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Some definitions
Embryos= early stages of developing
plants or animals
Comparative embryology= shows
relationships not obvious in the fully
grown organism.
pig and human
Comparative biochemistry= studies of
organisms on a biochemical level
blood and amino acids
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Anatomical Evidence for Evolution
• Strongest anatomical evidence supporting
evolution comes from comparisons of how
organisms develop.
• Early vertebrate embryos possess
pharyngeal pouches that develop into:
– In humans: glands and ducts
– In fish: gill slits
Complete embryonic development
w/s at this time!!!!
Day 3- STOP
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Day 4- Start
Charles Darwin
I’m a
NATURALIST!
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What did he do?
Formed the Theory of
Evolution which states
that:
– Species change over
time and space
– All organisms share
common ancestors with
other organisms
• Populations divide
into different species
– Evolutionary change is
gradual and slow
Click here for video!
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A struggle for existence!!!1st clue
Natural selection= one of the basic
mechanisms of evolution, along with
mutation, migration, and genetic drift.
There are 4 parts!!!!
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1.
There is variation in traits.
For example, some beetles are green
and some are brown.
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2.
There is differential reproduction.
Since the environment can't support unlimited
population growth, not all individuals get to
reproduce to their full potential. In this
example, green beetles tend to get eaten by
birds and survive to reproduce less often than
brown beetles do.
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3.
There is heredity.
The surviving brown beetles have
brown baby beetles because this trait
has a genetic basis.
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4.
End result:
The more advantageous trait, brown
coloration, which allows the beetle to have
more offspring, becomes more common in
the population. If this process continues,
eventually, all individuals in the population will
be brown. Remember the horses????
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nd
2
clue- Artificial Selection
=intentional reproduction of individuals
in a population that have desirable
traits.
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Click here for video
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Artificial Selection
Agriculture
Corn looks very different from its ancestor
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Artificial Selection
Over time, we have selectively bred hogs
to be leaner.
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Artificial Selection
Can
selection
produce
major
evolutionary
changes?
video
Breeds of dogs: The differences among
dog breeds are greater than the differences
displayed among wild species of canids.
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Day 4- STOP
Day 6
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Day 7 Population Genetics
=an entire population evolves, not just
an individual
and
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Some definitions
Gene pool= total of all genes, or genetic
information, in any population
Allele Frequencies= the number of
copies of a particular allele divided by
the number of copies of all alleles at the
genetic place (locus) in a population
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