1. Evolution Continued: Evidence & Other Concepts
Paleontologists have long thought that Archaeopteryx fossils, including this one discovered in Germany, placed the dinosaur at the base of the bird evolutionary tree; evidence suggests the beast may have been a birdlike dinosaur. CREDIT: Humboldt Museum für Naturkunde Berlin
Evolution Continued: Evidence & Other Concepts

2. On the following slides, the orange sections identify the main points; Underlined words = vocabulary! Hyperlinks are in green.

3. Today, most of the evidence for evolution is grouped into these main categories:
Fossil Record
Biogeography
Homologies
Anatomy
Embryology
Molecular
Observable Events
The Evidence of Evolution Use the information on the following slides to complete your “Matching Notes” student sheet.

4. Evidence Concept Map

5. 1 - FOSSIL RECORD Watch “Fossils As Evidence for Evolution”
Most fossils are found in layered sedimentary rock
Older fossils = lowest layers
Comparing fossils from different layers shows:
Life on Earth has changed
Increased biodiversity
1 - FOSSIL RECORD Watch “Fossils As Evidence for Evolution”

6. Fossils Cont. Paleontology – study of fossils Types of Fossils:
Remains: EX bone, tooth, or shell
Traces: EX burrow, footprint, or imprint
Dinosaur fossil searcher Ray Stanford discovered a large fossil of a Nodosaur just a few feet from this spot.
Tracy A. Woodward / THE WASHINGTON POST
Fossils Cont.

7. 2 – Biogeography Watch “Biogeography As Evidence for Evolution”
Biogeography: the geographic distribution of organisms
organisms living widely apart (even different continents), may be similar because they share a common ancestor
Beaver
Muskrat
Beaver and Muskrat
Coypu
Capybara
Coypu and Capybara
2 – Biogeography Watch “Biogeography As Evidence for Evolution”

8. 3 - Homologies: Anatomy Watch “Anatomical Development and Homologies as Evidence for Evolution”

9. Homologous structures: w/ similar structure, but different function show an evolutionary relationship
EX limbs of vertebrates (turtle, alligator vs. mammal)
Anatomy Cont.

10. Vestigial structures: reduced in size, are nonfunctioning remnants of similar structures in ancestral species
Show an organism’s evolutionary past
Ancestral species would have similar structures that are still functioning
EX human tailbone, appendix, whale femur/pelvis
Anatomy Cont.

11. Can you spot the vestigial limbs? (Photo Credit: Marc Mythos)

12. 4 - Homologies: Developmental (Embryology)
Embryos of different species may appear similar in early stages of development
Can show developmental relationships
4 - Homologies: Developmental (Embryology)

13. 4 - Homologies: Developmental (Homeobox/Hox Genes)
Hox genes: found in animals, determine the pattern of the body during development
Control transcription factors
Can show genetic relationships
4 - Homologies: Developmental (Homeobox/Hox Genes)

14. 5 – Homologies: Biochemistry
The genetic code [GCAT] is the same in all organisms
Triplets (or codons) of DNA bases code for specific amino acids to build proteins
5 – Homologies: Biochemistry

15. Sequence of amino acids in a particular protein is compared between organisms
AA Sequencing is probably the strongest evidence for relationships among organisms
Cladogram: diagram that shows the evolutionary relationship among a group of organisms.
Biochemistry Cont.

16. Some changes in species have been observed and studied in recent times
Observable events show that evolution is an ongoing process
P. & R. Grant’s Study of Beak Size Shift in Darwin’s Finches
H. Kettlewell’s Study of Peppered Moth Color Shifts
Observable Events

17. Species: a group of organisms that breed with one another and produce fertile offspring
Speciation: the formation of a new species as a result of evolutionary change caused by certain isolating mechanisms
Isolating Mechanism Animation
Speciation

18. Isolating Mechanism: Reproductive Isolation
Two populations become reproductively isolated from each other
Members cannot interbreed so the genetic material becomes too different
Spotted owl subspecies living in different geographic locations show some genetic and morphological differences.
Isolating Mechanism: Reproductive Isolation

19. Isolating Mechanism: Behavioral Isolation
Photo Credit, Mike Eggett
Two populations are capable of interbreeding, but have differences in courtship rituals, etc that involve behavior.
EX two different species of cricket that would be indistinguishable unless you heard their mating songs a noticeably different pitch 
Video
Cricket songs
Isolating Mechanism: Behavioral Isolation

20. Isolating Mechanism: Geographic Isolation
Two populations are separated by geographic barriers
EX rivers, mountains, or bodies of water
Isolating Mechanism: Geographic Isolation

21. Isolation Mechanism: Temporal Isolation
Two species reproduce at different times.
Photo Credit, Christian Ziegler
Populations may mate or flower at different seasons or different times of day. Three tropical orchid species of the genus Dendrobium each flower for a single day; the flowers open at dawn and wither by nightfall. 
Britannica
Isolation Mechanism: Temporal Isolation

22. Do a population’s genes (or gene pool) change over time? Yes!
% of an allele in a gene pool = allelic frequency
Genetic equilibrium: frequency of alleles remains the same
A population in equilibrium is NOT evolving
Influenced by
Environment, mutations
Genetic drift
Video
Genetic Equilibrium

23. Types of Evolution: Divergent Evolution
Adaptive radiation: type of divergent evolution; ancestral species evolve into an array of species to fit diverse habitats
EX Galápagos Finches
Video
Types of Evolution: Divergent Evolution

24. True or False? The shark and the dolphin are closely related?

25. Types of Evolution: Convergent Evolution
Convergent evolution: when unrelated species occupy similar environments, evolving similar traits, but are NOT closely related
Convergent evolution results in analogous structures
EX Bat wing vs. butterfly wing
Types of Evolution: Convergent Evolution