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The Grand and the Great
The Grand and the Great
Genetically and biologically, the most successful amongst us is the one that ends up with the most Grandchildren.Â
With mate selection You choose a mate that is as high up the 'fit' scale as you yourself can obtain.Â
You then have children, as many as you can without reducing the likelihood of success for any of them
In modern times, to ensure your child is 'fit' themselves, your likelihood of having grandchildren can be enhanced by not having as many children as is possible. Rather, because of the 'cost' of each of them, you may choose to use contraception.Â
These children then need to survive to reproductive age with competitive traits that will mean that 'fit' mates will select them to have children with
Congratulations, your grand children are arriving. But the human species is not done with you yet.Â
It turns out that we live for far longer time than all other large mammals because by sticking around for a while, you increase the chances of your own grandchildren making it to reproductive age, being 'fit', doing good mate selection and making Great Grand Children.
This is also because in ancient times there was a high chance of the new parents being killed by tribal warfare or disease, and thus the grandparents would then have to raise their grand children.Â
Variation of 'Fit'
Variation of 'Fit'
There is variation in the ranking challenge in terms of the exact placings, not all of the number 1 positions were filled with the same person, likewise for all of the numbers.
So although the trend is the same, we still look for different subtle traits (Freud would say a few things here, but I wont).Â
Likewise, most people working in film are fit. However, who is the fittest varies depending on who you ask
So there is variation within mate selection. So mate selection is random chance, being as 'fit' as each other, and variation within that range of 'fit' for each other
On Married at First Sight there is a challenge where participants 'rank' the photographs of the opposite gender participants in terms of attractiveness. This is effectively a one sided look at mate selection
When you watch this the overall trend is the same, but there is variation within the exact placings.Â
Because the variation trend is the same, it indicates that there are universals for human fitness
if you wear glasses, wear contacts instead
if you are skinny, work out
You can see that people already know this. Social media 'influencers'. They use lighting, photo editing and filters that enhance the mate selection traits.Â
Mate selection is the most important source of variation as kids inherit traits from their parents.Â
But you can only choose a mate from the available pool - so if you can only choose from a small village, there might be some issues.
Then there is variation amongst siblings due to Cross Over, Independent Assortment and Random Fertilization
These traits might be on a 'spectrum' like height, or it might be an either either like sex, either biologically male or biologically femaleÂ
Types of VariationÂ
Types of VariationÂ
Discontinuous Variation
Discontinuous Variation
Traits that are one thing or the other are called Discontinuous
These include eye colour
ability to roll your tongue, hitch-hikers thumb
 blood type
These are usually controlled by few genes
Continuous Variation
Continuous Variation
Traits that are on a spectrum are called Continuous
These include height, skin colour, muscle mass
These are usually influenced by multiple genes
Continuous traits are often influenced by the environment
if you do not eat much meat growing up, due to economic conditions etc, then you might not get to your maximum height
if you spend the summer working as a Surf life saver, then your skin colour will darken
If you go to the gym (environment), you will put on muscle
The environmental changes will operate within the range that is determined by your genetics. So you might get browner by working as a Surf life saver, but you still wont be as brown as a person with Nigerian skin colour alleles
How does Variation occur?
How does Variation occur?
Mutations
The ultimate source of Variation is Mutations
Mutations create the different 'alleles' for each gene
If these mutations are bad, then they might be recessive and hidden. These might eventually be 'breed out' especially if they are very bad
If these mutations are good, then the individual will be 'fitter' and will thus have more children and the mutation will spread through the population as they will keep having more children
Meiosis and Reproduction
Cross over and independent assortment - unique gametes
Mate Selection - who?
Random Feralization - which gamete wins?
Environment
Exposure to nutrients and chemicals when developing in utero
For example, wartime starvation of pregnant women will lead to children whose bodies are designed for a famine environment and will thus convert more of their food to fat and will be fatter when exposed to a western diet
Exposure to nutrients, chemicals, and environmental conditions while growing upÂ
For example, wartime starvation of children will result in stunted growth along with other issues
On a positive, an active childhood will enhance muscle development and how 'fit' you are as an adult
Exposure to nutrients, chemicals, and the environment as an adult
If you work in a physically demanding job, you will be more 'fit' than someone who works in an office, unless the office person goes to the gym
If you work outside, your skin colour will be browner than it would be if you worked in an office
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