1. P. 107 EQ: What is evolution and what types of evidence are there?
Evolution Theory
P. 107
EQ: What is evolution and what types of evidence are there?

2. What is evolution?
Evolution is gradual change of heritable traits (determined by an organism’s alleles) in a population across generations, eventually generating new species over time.

3. Types of Evolution
Microevolution – idea that natural selection can, over time, take an organism and transform it into a more specialized species of that organism; can be seen & observed. ex: finches, tortoises This is essentially variations within an organism’s genetic code Macroevolution – idea that processes similar to those at work in microevolution can, over eons of time, transform an organism into a completely different kind of organism; can be inferred. ex: ancient giant armadillo-like creature & modern armadillo

4. Types of Evolution
Convergent Evolution – species with different ancestors becoming more similar
They have similar features because they lived in similar environments that favored that trait
Convergent evolution creates analogous structures
superficially similar form or function
different anatomy

5. Types of Evolution
Divergent Evolution – populations of a single species located in different environments become more and more different until they are different species These organisms may look different, but they have a common ancestor Divergent evolution creates homologous structures
Similar structure but different function
Common origin

6. Evidence for evolution
Many scientists believe the study of the following things provide evidence of common ancestry among groups:
- The Fossil Record
- Biogeography
- Homologies
Anatomical
Molecular
Developmental

7. Fossils
Preserved remains or evidence of an ancient organism Give us clues about an organism’s structure and the environment it lived in

8. Fossil Record
shows how life has changed on earth In a given rock layer, the oldest things should be at the bottom and the youngest things should be at the top
Younger
Older

9. Gradualism
Gradualism is the idea that small changes in a species over time will eventually result in a new species. This would create intermediate links between ancient species and modern species. (Do not write anything below this on this slide)
Archaeopteryx is believed to be a transitional form between birds and reptiles, and it is the earliest known bird.
Reptile features: had a full set of teeth, a rather flat sternum, a long, bony tail, gastralia ("belly ribs"), and three claws on the wing
Bird features: feathers, wings, furcula (wishbone), and reduced fingers

10. stasis
Most species exhibit no directional change during their tenure on earth. They appear in the fossil record looking much the same as when they disappear