1. Daily Warm-up February 14th
A mutation that does not cause an improvement or reduction in an individual’s ability to survive and reproduce is a _______ mutation.
HW:
-Read 16.4
-Have online simulations done by Monday
Turn in:
-Darwin map assignment and test corrections

2. Evidence of Evolution
16.4

3. 1. Biogeography Closely related but different
Galapagos Islands species different than those from South America
Distantly related but similar
Similar habitats lead to similar adaptations
Observed that animals on South American mainland were more related to each other than animals living in similar environments in Europe

4. 2. Fossil Record Provides a record of species that lived long ago
Similarities between ancient and modern species
Some remain relatively unchanged
Helps us determine ancestry and pattern of evolution
Transitionary fossils
Some limitations to fossil record- soft tissue organisms hard to preserve.
Hundreds of thousands of transitionary fossils
Archaeopteryx
Tik Taalik

5. Evolution of birds Archaeopteryx lived about 150 mya
links reptiles & birds
The avian nature of the brain and inner ear of Archaeopteryx (Alonso et al. 2004) - Archaeopteryx, the earliest known flying bird from the Late Jurassic period, exhibits many shared primitive characters with more basal coelurosaurian dinosaurs (the clade including all theropods more bird-like than Allosaurus), such as teeth, a long bony tail and pinnate feathers. However, Archaeopteryx possessed asymmetrical flight feathers on its wings and tail, together with a wing feather arrangement shared with modern birds. This suggests some degree of powered flight capability but, until now, little was understood about the extent to which its brain and special senses were adapted for flight. Alonso et al. (2004) investigated this problem by computed tomography scanning and three-dimensional reconstruction of the braincase of the London specimen of Archaeopteryx. A reconstruction of the braincase and endocasts of the brain and inner ear suggest that Archaeopteryx closely resembled modern birds in the dominance of the sense of vision and in the possession of expanded auditory and spatial sensory perception in the ear. Alonso et al. (2004) concluded that Archaeopteryx had acquired the derived neurological and structural adaptations necessary for flight. An enlarged forebrain suggests that it had also developed enhanced somatosensory integration with these special senses demanded by a lifestyle involving flying ability.
Smithsonian Museum, Washington, DC

6. Evolution of land animals
2006 Fossil Discovery of Early Tetrapod
“Tiktaalik”
“missing link” from sea to land animals
from swimming (0 legs) to walking (4 legs)

7. Evolution of marine mammals
Land Mammal ?
But then, they actually found my fossil!
Where are the transitional fossils?
There are innumerable intermediate & transitional forms
Whales as land creatures returning to the water….
Where are the intermediate forms of whale ancestors?
Cartoon making fun of this idea.
The cartoons disappeared years ago when this fossil was found.
Ambilocetic natans = “Walking whale who likes to swim”
4-5 intermediate forms all found in last 2 decades
Indus River valley in between India & Pakistan.
At first, I was just a joke!
Aquatic Mammal

8. 2. Comparative Anatomy
Examining similarities and differences in anatomy
Homologous structures
Similar structures shared with a common ancestor
Analogous structures
Similar function but no common ancestor
Analogous structures show that functionally similar features can evolve independently in similar environments

9. Homologous Structures

10. Analogous Structures

11. Vestigial Structures
Structures that are reduced forms of functional structures in other organisms.

12. Comparative Embryology
Vertebrate embryos display homologous structures during certain phases of development
May become completely different structures in adults

14. Comparative Biochemistry (DNA)
Molecular similarities
Should be those that organisms share
Cytochrome C- enzyme that is essential for respiration is found in many organisms
Evolutionary theory predicts that molecules in species with recent common ancestor should share certain amino acid sequences.
The more related, the more similarities.
Organisms with closely related morphological features have more closely related molecular features

16. 4. Direct Observations of Natural Selection

17. Homologous or Analogous?