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Evolution
Change through Time
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2. What You Should Know How To Explain at End of Unit…
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3. Evolution and Biodiversity Central Concepts:
Evolution is the result of genetic changes
that occur in constantly changing
environments. Over many generations,
changes in the genetic make-up of
populations may affect biodiversity
through speciation and extinction.
(CHANGE IN POPULATION THROUGH TIME)
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2. Explain how evolution is demonstrated by evidence from the fossil record, comparative anatomy (embryos), genetics, molecular biology, and examples of natural selection.
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3. Describe species as reproductively distinct
groups of organisms. Recognize that
species are further classified into a
hierarchical taxonomic system (kingdom,
phylum, class, order, family, genus,
species) based on morphological, behavioral,
and molecular similarities. Describe the role
that geographic isolation can play in
speciation.
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4. Explain how evolution through natural selection can result in changes in biodiversity through the increase or decrease of genetic diversity within a population.
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7. History of Evolutionary Thought

8. Early Ideas On Earth’s Organisms
Aristotle believed species were fixed creations arranged by their complexity

9. Early Ideas On Earth’s Organisms
Linnaeus – 1st to group similar organisms and assign them Latin names
Two word name (Genus species)
Known as Binomial nomenclature
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10. Taxonomy
King
Phillip
Came
Over
For
Good
Spaghetti

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USA Kingdom
MA Phylum
Taunton Class
Bristol-Plymouth Order
Room # Family
Jennifer Genus
Bisch Species
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12. Lamarck’s Theory of Evolution
Jean-Baptiste Lamarck, 1809
One Of First Scientists To Understand That Change Occurs Over Time
Stated that Changes Are Adaptations To Environment acquired in an organism’s lifetime
Said acquired changes were passed to offspring (NOT TRUE)
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13. Lamarck’s Theory of Evolution
Idea called Law of Use and Disuse
If a body part were used, it got stronger
If body part NOT used, it deteriorated

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15. Charles Darwin

16. Voyage of the Beagle Charles Darwin Born Feb. 12, 1809
Joined Crew of HMS Beagle, 1831

17. Darwin returned 5 years later in 1836
Darwin Left England in 1831
Darwin returned 5 years later in 1836
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The Galapagos Islands
Volcanic islands off the coast of South America
Island species varied from mainland species & from island-to-island species
Each island had long or short neck tortoises
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20. The Galapagos Islands - Finches
Finches on the islands resembled a mainland finch
More types of finches appeared on the islands where the available food was different (seeds, nuts, berries, insects…)
Finches had different types of beaks adapted to their type of food gathering (speciation)

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22. Darwin’s Observations & Conclusions
The Struggle for Existence
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Definition
Evolution is the slow , gradual change in a population of organisms over time
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24. Darwin’s Conclusion
Production of more individuals than can be supported by the environment leads to a struggle for existence among individuals
Only a fraction of offspring survive each generation
Survival of the Fittest through Natural Selection

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DAY 2
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Evidence Supports…
Either:
EVOLUTION – change over time
DESCENT WITH MODIFICTION
(We came from a common ancestor, but, have changed through time based on our environment.)
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27. Common Descent with Modification
Darwin proposed that organisms descended from common ancestors
Idea that organisms change with time, diverging from a common form
Caused evolution of new species (speciation)

28. Descent With Modification
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29. Evolution By Natural Selection Concepts
The Struggle for Existence (compete
for food, mates, space, water, etc.)
Survival of the Fittest (strongest able
to survive and reproduce)
Natural Selection
Descent with Modification (new species arise from common ancestor replacing less fit species)
EVOLUTION
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30. Natural Selection Cannot Be Seen Directly
It Can Only Be Observed As Changes In A Population Over Many Successive Generations
Radiation
Fossil Record

31. Speciation The formation of new species Results from: Genetic Drift
Gene Flow
Temporal isolation
Geographic Isolation
(HAPPENS BY ACCIDENT)
(MOVEMENT IN OR OUT)
(TIMING OFF)
(SEPARATED)

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33. Theory of Evolution Today
Evidence
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34. Fossil Record Earth is Billions of Years Old
Fossils In Different Layers of Rock (sedimentary Rock Strata) Showed Evidence Of Gradual Change Over Time

35. Similarities in DNA Sequence (molecular evidence) best one!

36. Analogous & Homologous Body Structures
They have separate evolutionary origins, but are superficially similar because they have both experienced natural selection that shaped them to play a key role in flight (lived in similar environment). Analogies are the result of convergent evolution
They have traits that are similar
because they were inherited from
a common ancestor 

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Convergent Evolution
Process whereby organisms not closely related independently evolve similar traits as a result of having to adapt to similar environments or ecological niches.
Divergent Evolution
Process whereby organisms closely related independently evolve different traits as a result of having to adapt to different environments or ecological niches.
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38. Homologous Structures

39. Vestigial Organs
Vestigial Organs
Appendix In Man
Hip bone in whale

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Embryonic Evidence
Embryonic Structures Of Different Species Show Significant Similarities
Embryo – early stages of vertebrate development
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Evidence for Evolution - Comparative Embryology
Similarities In Embryonic Development
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Modes of Selection
Stabilizing Selection – average trait is advantageous
Disruptive Selection – both extremes are advantageous
Directional Selection – one extreme is advantageous
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