Evolution

Evolution: The change over time in the characteristics of a population

Core Principles:

• All life is linked through a common ancestor

• evolution is the product of change in a population, not an individual

• advantageous traits are selected over less advantageous traits

• traits passed down from generations

Early Proposed Mechanics of Evolution:

• all organisms thought to be fixed (non changeable)

• 1809, Lamarck hypothesized organisms evolved through inheritance of acquired characteristics

• acquired characteristics is the process of bodies being modified during lifetime through use/disuse of different parts inherited by offspring

• we now know this isn’t true

Darwin & HMS Beagle:

• 1831, five year survey to the Galapagos Islands

• noticed lots of similar birds, slightly different characteristics

Darwins Theory - Theory of Natural Selection (Alfred Wallace had similar insights)

How Natural Selection Works: (4 Postulates)

1. Individuals vary

2. traits are inherited

3. some individuals fail to survive & reproduce

4. reproductive success is not random

Early Genetics:

• Darwin believed in more advantageous genes, inside some information packets (now know as genes)

Opposition of Evolution

• nature of historical evidence

Physical Evidence:

• Fossil Record

• Radiometric dating

• Comparative anatomy

• comparative embryology

• Molecular similarities

• bio chemical processes

Fossils - found in older rocks

Evidence:

Comparative Embryology

• Early embryo development in all vertebrates go through similar stages

Molecular Similarity

• allows us to know more about genes

• shows what we have in common

Universal Biochemical Processes:

• all cells, all living things have DNA and RNA

Artificial Selection:

• Controlled breeding to produce desirable traits