1. Evolutionary trends
By Martin Samaj

2. Rates of evolution
Gradualism – claims that evolution proceeds very slowly, large changes can occur over long periods of time
This theory does not fit with fossil record, which show periods where the evolutionary rate was stable, followed by a period of rapid changes
These changes in evolutionary rates may be due to the environmental changes which would require the species to adapt to these new conditions
This view of the pace of evolution is called punctuated equilibrium

3. Adaptive radiation
When each species evolves in a different way, we call it divergent evolution
Adaptation to different ecological roles avoids competition among species
If species in a group deviate rapidly it is called adaptive radiation
Example: when a group has a characteristics that gives it a competitive advantage over existing species
Mammals also demonstrate adaptive radiation – the pentadactyl limb

4. Transient polymorphism
Population in which there are two alleles of a gene in the gene pool is polymorphic
If one allele is gradually replacing the other the population shows transient polymorphism
The peppered moth is an example of this

5. Convergent evolution
Living organisms often find the same solutions to particular physiological problems
If natural selection acts the same also in other parts of the world, species can become remarkably different despite not being closely related at all
This is called convergent evolution
Instead of closely related species showing striking differences, unrelated species show striking similarities

6. Balanced Polymorphism
Sometimes alleles of gene can persist indefinitely in the gene pool of a population
This is called balanced polymorphism
The most researched example of this would be sickle anemia
Heterozygous individuals do not develop sickle cell anemia and are resistant to sickle cell anemia

7. Danke for paying attention