Natural Selection and Selective Breeding

Hiya!

Hope this week has been a good end to January and it seems you've, naturally, selected to view my blog so without further ado, happy reading!

Individuals of the same species can reproduce to form fertile offspring.This means if two lions reproduce, their lion offspring can also go on to reproduce. Naturally, within a population of a species, there is variation due to two main factors; differences from parental inheritance and mutations in genes. The mutations occur when the gametes are formed and they may affect the phenotype (physical characteristics) of their offspring. Although many mutations are relatively unnoticeable, some mutations can have significant impacts on an individual. If a mutation is harmful or unhelpful, the organism is unlikely to survive and will not live on to reproduce however is a mutation is advantageous then the organism is likely to live on to reproduce and pass this characteristic onto its offspring.

Some cute butterflies which remind me of a
 butterfly I once looked after. How's that for a backstory?(Suzanne D Williams)

Evolution is the process by which different kinds of living organism are believed to have advanced from earlier forms during the history of the Earth. Many scientists believe this is due to the process of natural selection. The theory of evolution suggests a number of things;

• Individuals in a species show a wide range of variation
• This variation is due to differences in genes or mutations
• Individuals with advantageous characteristics are more likely to survive and reproduce
• The genes that allowed the individuals to be successful are passed onto the offspring of the successful organisms
• The successful genes are passed on through generations and the number of organisms with this characteristic increases in future populations
• Organisms with unsuccessful or disadvantageous characteristics will die and decrease in population causing this gene not to be passed on

A commonly referred to example of natural selection is the case of the moths during the industrial revolution. Before the industrial revolution, light-peppered moths were the predominant variation of peppered moths as they could camouflage from predators (birds) by blending in with the trees. The revolution sparked a vast increase in pollution, causing the lichens (plants that grow on the bark of trees) to become darker. Naturally, within a population of moths there is variation due to differences in genes and mutations. This variation caused there to be dark peppered moths which were more able to camouflage with the lichens on trees in industrial areas. As these dark peppered moths had an advantageous phenotype (physical characteristics), they were able to camouflage well from predators and reproduce effectively. Over time, light peppered moths died out and dark peppered moths made up a significant proportion of the moth population in industrial areas.

A cute moth (Ruben Marques)

Selective breeding is "selecting individuals with desired characteristics and breeding them together so that more of the next generation have the desired characteristics". In more basic terms, we breed organisms with good qualities together to produce even better organisms. We can selectively breed individuals for a number of reasons:

• Behaviour (animals)
• Good quality milk, large eggs (animals)
• Appearance e.g fur, skin (animals)
• Disease resistant (plants)
• Wheat that produce high yields (plants)
• Large or unique flowers (plants)

Selective breeding is good because it allows us to create products with desired characteristics e.g large eggs and good quality milk. It can also help economically to produce higher yields of crops and allow us to breed animals with desired characteristics like good fur or allergy free cats. However, selective breeding also has many problems;it can reduce variation within populations and increase risks of recessive diseases/conditions we may not be aware of. Additionally, it can create more immediate physical problems with formation like pugs and respiratory conditions.

Golden hour to counteract this bitter weather(Mark Erskine)