1. Evidence for Evolution
Honors Biology

2. What is the Evidence of Evolution?
Darwin Argued That Living Things Have Been Evolving On Earth For Millions of Years. Evidence For This Process Could Be Found In:
The Fossil Record
Biogeography (the Geographical Distribution of Living Species)
Homologous Structures of Living Organisms (Comparative Anatomy)
Embryology

3. Evidence for Evolution http://www. sumanasinc
Homology
a similarities in characteristic traits resulting from common ancestry
Anatomical Homologies (Comparative Anatomy)
From a common ancestor
Called HOMOLOGOUS STRUCTURES
Same structure and development, but different function
Examples = Vertebrate limb bones, bird feathers/mammal hair

4. Homologous Structures
Homologous structures are structures (body parts) that are anatomically similar structures inherited from a common ancestor but different function.

5. LE 22-14
Human
Cat
Whale
Bat

6. Comparative Anatomy 3) Analogous Structures:
Through convergent evolution
Convergent evolution the evolution of a species from different ancestors toward a similar (not the same!) form
Structures that perform a similar job, but are not from a common ancestor
Example = bird wing, bat wing, and an insect wing

7. 4. Vestigial organs
remains of structures/organs that ONCE had an importance in organism’s ancestors
Example: tailbones in humans, appendix, wings on ostrich, wisdom teeth in humans, nipples in male mammals, femur and pelvis in whales

8. 5. Comparative Embryology

9. Embryology
Embryology is a new method of examining evidence of evolution
Embryo = first 9 weeks of vertebrate development
Embryonic structures of different species show significant similarities
By studying the same patterns of early development across many different animals, we can find evolutionary links between animals

10. 6. Molecular Homologies
Similar genes (DNA), RNA or amino acid sequences
Example
genes shared among organisms inherited from a common ancestor
Ex #1: Homeobox is a DNA sequence in genes that regular development in plants, animals and fungi

11. Human Rhesus monkey Mouse Chicken Ex #2: Amino Acid/ Frog
LE 22-16
% of Amino Acids That Are
Identical to the Amino Acids in a
Human Hemoglobin Polypeptide
Species
Human
100%
Rhesus monkey
95%
Mouse
87%
Chicken
69%
Ex #2: Amino Acid/
Protein sequence
Frog
54%
Lamprey
14%

12. 7. Biogeography the geographic distribution of species Sugar Glider
Marsupial
Flying
Squirrel
Eutherian
(placental)
Some similar mammals that have adapted to similar environments have evolved independently from different ancestors

13. 8. Genetic Changes over time
Bacteria becomes resistant to antibiotics

14. Paleontologists have discovered fossils of many transitional forms
9. Fossil Records
Paleontologists have discovered fossils of many transitional forms
Shows variety on organism across time

15. The Fossil Record Earth is BILLIONS of years old
Fossils in different layers of rock showed evidence of gradual change over time
Paleontologists have discovered fossils of many transitional forms
Example- Whales have an excellent fossil record-showing transitional forms

16. The Fossil Record
The succession of forms in the fossil record clearly suggests that organisms change through time, and have descended from a common ancestor
Different groups appear in the fossil record at different times, with a general trend toward the simplest organisms appearing the EARLIEST

17. RECALL: Evidence for Evolution
Fossil record
Comparative Anatomy
Homologous structures
Analogous structures
Comparative Embryology
Vestigial structures
Molecular biology (DNA/RNA/protein amino acid differences)
Biogeography
Field studies

18. Natural Selection vs. Artificial Selection
Recall Natural selection
In artificial selection,
humans modify other species over many generations by selecting and breeding individuals with desired traits

22. Key Concepts
What is the raw material necessary for the mechanism of Natural Selection?
Heritable variations
What is the smallest unit of evolution?
Populations (NOT individuals)
Darwin incorporated Lyell’s gradualism into biological evolution combined with Malthus’ observations regarding populations

23. Is Evolution JUST a THEORY??? Is it SCIENCE based?
accounts for MANY observations and data
attempts to explain and integrate a great variety of phenomena
Video #1: Isn’t Evolution Just a Theory?

24. copyright cmassengale
Cladogram
Diagram showing how organisms are related based on shared, derived characteristics such as feathers, hair, or scales
copyright cmassengale

25. Outgroups vs. Ingroups Outgroup Ingroup
The species or group of species that is closely related to the ingroup
Distinguishes between shared primitive and shared derived characteristics
Closely related to ingroup
Ingroup
the various species we are studying

27. What is the shared primitive characteristic? Notochord
A Cladogram
What is the shared primitive characteristic? Notochord

29. Lamprey

30. Aminion
The amniotic sac is a bag of fluid inside a woman's womb (uterus) where the unborn baby develops and grows. It’s sometimes called the ‘membranes’, because the sac is made of two membranes called the amnion and the chorion.

31. Placenta

32. Foramen magnum