Download Evidence for Evolution - Fall River Public Schools

Evidence for
Evolution
B.M.C. Durfee High School
Objectives
• Describe the evidence that supports the
Theory of Evolution
• Describe how fossils can be made
• Explain how the Law of Superposition can be
used as evidence of the Theory of Evolution
Evidence for Evolution
• What do we know about evolution
o Change in species over time
o Darwin explained using Natural Selection
o Natural Selection: Individuals with traits
that are more favorable in a particular
environment are more likely to survive and
reproduce
o NeoDarwinian Evolution also says that
Mutation, Gene Flow and Genetic Drift
contribute to evolution
What evidence is there for
evolution?
• There are lots of forms of evidence for
evolution:
o Comparative Anatomy
 Homologous Structures
 Vestigial Structures
o Embryology
o Biogeography
o Comparing Macromolecules
o Fossils and Law of Superposition
Comparative Anatomy
• Evolution is a continuous process and by
examining genotypes and phenotypes in
modern organisms we can see that evolution
has occurred
• Since organisms change through a process of
gradual modifications we can see evidence of
their evolutionary history
Homologous Structures
• Homologous features are similar features that
are found in organisms that share an
evolutionary relationship
o Wings in Eagles and wings on a chickadee
o Opposable thumbs on monkeys and
humans
o Forelimbs: penguin, alligator, bat, human
Analogous Structures
• Analogous features have identical functions
and look alike
• Have different embryological development
and may have different internal anatomy
• No evolutionary relationship
• Bird and insect wings
Vestigial Structures
• These are structures with no useful function
o Human tail bone, appendix
o Whales with pelvic bones; limb bones in
snakes
• Features were useful to ancestor but not
useful today
• Understand evolutionary past
Embryology
• Early stages of vertebrate embryos are similar
• Ontogeny recapitulates phylogeny – embryo
development repeats evolutionary history –
gills and fins
Biogeography
• Study of distribution of fossils and living things
• Organisms are compared with fossils in the
area; similar in forms
• Modern kangaroos only live in Australia where
the extinct giant kangaroo lived
Similarities in Macromolecules
• More similar forms of organisms have a more
recent common ancestor than less similar
forms
• Compare proteins, DNA and RNA molecules
Similarities in Macromolecules
• Amino acid sequences in hemoglobin are
similar but not identical
o Humans and gorillas differ by one amino
acid
o Humans and frogs differ by 67 amino acids
• The more time passed, the more differences
between amino acid sequences; more amino
acids shared the more recent they were
Fossils
• Fossil is a trace of a long-dead organism
• Usually in rock when sediment is deposited by
wind and water
• Develop from hard parts of body (teeth,
bones, etc.)
Fossils…
•
•
•
•
Hard mineral replace organic tissue
Molds are imprints of living thing
Cast are rock like models of organisms
Mosquitoes trapped in amber are fossils,
footprints, tracks
Law of Superposition
• Layers of soil get deposited on top of each
other; Lowest layers are oldest and top are
youngest (stratum)
Lucy Video
Evolution Finding Lucy Becoming a Fossil
Review
• Describe the evidence that supports • Comparative Anatomy
the Theory of Evolution:
• Embryology
• Biogeography
• Comparing Macromolecules
• Fossils and Law of Superposition
• Describe how fossils can be made:
• Develop from hard parts of body (teeth,
bones, etc.)
• Hard mineral replace organic tissue
• Molds are imprints of living thing
• Mosquitoes trapped in amber are
fossils, footprints, tracks
• Layers of soil get deposited on top of
• Explain how the Law of
each other; Lowest layers are oldest and
Superposition can be used as
top are youngest
evidence of the Theory of Evolution:
Learn Long
Live Long