Download Evidence for Evolution

Evidence for Evolution
Chapter 22
Big Idea 1: The process of evolution
drives the diversity and unity of life
Enduring Understanding 1.A: Change in
the genetic makeup of a population over
time is evolution
Essential knowledge 1.A.4: Biological
evolution is supported by scientific evidence
from many disciplines, including
mathematics.
a.
Scientific evidence of biological evolution uses
information from geographical, geological,
physical, chemial and mathematical
applications.
1.A.4
b.
Molecular, morphological and genetic information
of existing and extinct organisms add to our
understanding of evolution.
1. Fossils can be dated by a variety of methods that provide
evidence for evolution. These include the age of the
rocks where a fossil is found, the rate of decay of
isotopes including carbon-14, the relationships within
phylogenetic trees, and the mathematical alculations that
take into account information from chemical properties
and/or geographical data.
X The details of these methods are beyond the scope of this
course and the AP Exam
2. Morphological homologies represent features shared by
common ancestry. Vestigial structures are remnants of
functional structures, which can be compared to fossils
and provide evidence for evolution.
1.A.4.b
3.
Biochemical and genetic similarities, in particular DNA
nucleotide and protein sequences, provide evidence for
evolution and ancestry.
4. Mathematical models and simulations can be used to illustrate
and support evolutionary concepts.
To foster student understanding of this concept, instructors
can choose an illustrative example such as:

Graphical analyses of allele frequencies in a population
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Analysis of sequence data sets
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Analysis of phylogenetic trees
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Construction of phylogenetic trees based on sequence data
Learning Objectives:
LO 1.11 The student is able to design a plan to answer scientific
uestions regarding how organisms have changed over time using
information from morphology, biochemistry and geology. [See SP
4.2]
LO 1.12 The student is able to connect scientific evidence from
many scientific disciplines to support the modern concept of
evolution.
What you need to know!
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Several examples of evidence for
evolution.
The difference between structures
that are homologous and those that
are analogous, and how this relates
to evolution.
The role of adaptations, variation,
time, reproductive success, and
heritability in evolution.
Types of Evidence

1.
2.
3.
4.
Evidence for evolution is provided
by 4 scientific principles
Direct observations
The fossil record
Homology
Biogeography
Direct Observations
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Wild guppies w/ plain colors
The common cold and flu
Drug resistant bacteria and viruses
Peter and Rosemary Grant’s work on
finches
• Beak sizes changed from one generation
to the next based on environmental
factors

Pesticide resistant insects
Fossil Record
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Paleontology is the study of
fossils
Fossils are remains or
traces of life in sedimentary
rock
Substantial, but incomplete,
chronicles of evolutionary
history
Transitional fossils have
been found that link ancient
organisms to modern
species
Coincides with
biogeographical
understanding (continental
drift)
Fossil Record
Homology

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Def: traits in related
species can have
underlying similarity
w/ different function
Homologous
Structures:
• structural similarity of
body due to common
ancestry
• functionally dissimilar
Homology

Embryonic
homologies
are the
notable
anatomical
similarities
in the
embryonic
development
of animals
Homology

Vestigial Structures: anatomical
structures that ancestors used but
now have reduced (or no) function
Homology
Molecular homology includes a variety of
similarities:
 All organisms share the same genetic
code (DNA/RNA triplets/codon)
 The closer related a species, the higher
the percentage of identical DNA
• Chimp and human DNA is 98% identical
• Bird and Human DNA is only 60% identical
• Plant and Human DNA is only 10% identical
Homology

Convergent Evolution:
unrelated species around
the world look similar
when found in similar
environments (analogous
structures)
Biogeography

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Def: geographic distribution of species
Species tend to be more related to
nearby species
• i.e. desert animals in South America are
more related to local animals in other
habitats than to African desert species
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Continental drift explains the similarity of
species on different continents
Endemic species are species unique to
one specific environment (marine
iguanas)