Warm-Up 8/29/16 Define the following terms: Allele Genotype Phenotype Gene Pool Population Genetics

Evidence for Evolution 1. Fossil Record 2. Molecular 3. Developmental 4. Anatomical 5. Biogeographical Fossil of Archaeopteryx, ancient bird

1. Fossil Record Fossils form in sedimentary rock Older forms are in lower layers of rock; newer, more complex forms in upper layers Demonstrates that organisms have changed over time due to position in rock layers

2. Molecular homologies Number of changes in amino acids indicates divergence away from common ancestor Change in amino acids indicates change in genetic code Comparing DNA and protein structure of organisms.

3. Developmental Similarities Hox genes are common to most organisms Hox genes = code for basic body plan Note that the Hox genes for the mouse, fly and human generate similar body regions as well as body parts Hox genes code for basic body plan. Note that they generate similar body regions.

Embryological Similarities Which is the human? Which is the human? Vertebrate embryonic development proceeds in similar fashion among vertebrate species Note the presence of gill slits and a post-anal tail in each of the vertebrate embryos above. If development proceeds similarly, then genes that direct that development must also be similar.

4. Homologous Structures traits inherited by two different organisms from a common ancestor Homologous structures have similar construction but are used for different purposes Homologous structures indicate common ancestry due to structure being similar Since structure is similar, genes for these structures must also be similar

similarity due to convergent evolution, not common ancestry 4. Analogous Structures similarity due to convergent evolution, not common ancestry Process in which two distinct lineages evolve a similar characteristic independently of one another. This often occurs because both lineages face similar environmental challenges and selective pressures. In evolutionary biology, convergent evolution is the process whereby organisms not closely related (not monophyletic), independently evolve similar traits as a result of having to adapt to similar environments or ecological niches.

10 Human Vestigial traits 4. Vestigial Structures Vestigial structures are structures that are reduced in size because they are not used or needed Examples are the pelvis found in whales (they are descended from four-legged mesonychids, dog-like creatures; hence the reason they are mammals) Snakes have vestigial legs (felt on the undersides of their bodies) Humans have many vestigial organs: the appendix (at one time was a cecum, still present in herbivores) Muscles that wiggle the ears (our ears generally do not wiggle or cock up like those of dogs and cats) Wisdom teeth are thought to be vestigial; they are the 4th molar, which we do not typically use. Some people do not even have wisdom teeth as they do not erupt 10 Human Vestigial traits

5. Biogeography How species are distributed and evolved within island systems Biogeography refers to the distribution of species, usually within island systems Island ecosystems are unique in that species found there are not usually found elsewhere due to isolation from mainlands Galapagos is a unique archipelago, off the coast of Ecuador Also Hawaii, Australia, other island systems.