1. EVOLUTION
The process of cumulative change in the heritable characteristics of a population
One change is not enough to have major impact on species
Changes must be passed on genetically from one generation to the next
Changes do not effect on individual
Evolution takes time
Change + Change + Change New species = speciation

2. The Fossil Record
Life that existed more than 500 million years ago was vastly different in appearance
Top predators today (mammals) – none existed before the dinosaurs
Apart from select species, majority of living organisms today have no similar fossil form
Though oceans have existed for majority of earth’s life, fish fossils only date back 500 mya

3. Aging Fossils
After 5730 years, 50% 14C remains, 50% 14N has been created
Radioactive Carbon Dating – 14C
High 14C – younger bone/shell
Low 14C – older bone/shell
Decay: radioactive parent isotope (14C) changes into stable daughter isotope (14N)
Rate of occurrence = half-life
Insufficient 14C, use 40K

4. Artificial selection
Provides a good record of recent changes in heritable characteristics
Breeders learned to choose the males and females with the most desirable genetic characteristics and breed them together
Certain varieties of animals had unique combinations of characteristics which did not exist before
Is evidence that evolution is happening due to an accumulation of small changes over time, however it is certainly not the driving force of evolution in natural ecosystems

5. Homologous Structures
Structures that are similar in form and function but found in seemingly dissimilar species
Pentadactyl limbs
Shapes and number of bones vary, the general format is the same
All species have different mode of locomotion
Evidence that the organisms in question have a common ancestor
Bones different size, varied morphology – but position is the same
Whales could swim with different number of fingers – but have 5

6. Homologous Structures
Shows species divergence
Two species can no longer interbreed

7. Homologous Structures
Adaptive Radiation
Similar by distinct species evolve relatively rapidly from a single species or small number of species
Natural selection or presence of a barrier  causes change
position/role within community
Exploit slightly different niche more successfully

8. Lemurs live on Madagascar and Comoro Islands
No monkeys or apes present
Large variety  adaptive radiation
Fossils found on other continents – but none living
Some:
Live on ground
In trees
In rainforest
In desert
Could not compete with monkey/apes

9. Representation of species with their common ancestor
Continuous variation across geographical range
Selective pressure
Measurable differences in DNA (due to environmental stimuli)
Some genes selected for others selected against
Overtime - speciation

10. Transient polymorphism
Different versions of a species – caused by mutations
Moth: peppered (grey) or melanic (black)
Common
Mutation in 1% of population
During industrial revolution: melanic form increased in numbers (95-100%) reversed cameoflage
Blend into their natural habitat – white bark of trees
Current day: percentage of type of peppered moth found depends on locale and pollution levels
Melanic – 0-30% due to clean air acts