Variation
The Grand and the Great
Genetically and biologically, the most successful amongst us is the one that ends up with the most Grandchildren.
With mate selection You choose a mate that is as high up the 'fit' scale as you yourself can obtain.
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.
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.
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.
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).
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
Gender itself is more a spectrum due to the gender diverse enhancing the survival of the species by bridging gaps in the male and female psychology and sociology - the BBC clip on the side is an interesting insight.
Always be kind, life is harder for many people, be aware that the world is far more complex than any of us can comprehend and there is no one way to do life
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.
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.
Mate selection is the most important source of variation as kids inherit traits from their parents.
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 female
Types of 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
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
Genetic Science and Variation
Sources of Variation
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
Genetics:
Mate Selection
Cross over and independent assortment
Random Feralization
Environment
Exposure to nutrients and chemicals when developing in utero
For example, war time starvation of pregnant woman will lead to children whos 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 up
For example, war time starvation of children will result in stunted growth along with other issues
On a positive, a 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 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
Why is Variation Important
Variation is important as it increases the likelihood of the species surviving environmental change
This change can be in the physical environment, it could be due to the arrival of a new species to the environment or it could be due to disease
Giraffes
Millions of years ago, the Savanna of Africa was not there, rather it was Trees and Green
But, then the climate changed, it rained less and the trees started to become fewer and fewer
This made it harder to hide from predators
So, if there was a taller member in the group, they could spot predators sooner and they could run away
Thus the groups with shorter members died out as they were eaten
This pushed the necks longer and longer as those groups that had the tallest members survived the best.
At the same time they could access food that was higher up in the trees that the shorter families could not
Climate change has been a major driver for evolution, including our own
Our ancestors lived with these Giraffes in Africa, living amongst the trees. Climbing in the trees and walking on all fours
Climate change removed the trees, those families that could stand and look around could spot predators faster
This ability to stand and walk on 2 legs favored those that did this most naturally, so this trait was passed on. And who ever did this the best in each generation had the most offspring
The problem with climate change now is that it is happening too fast for organisms to be able to evolve to match it. Evolution requires mutations, then mating, then babies, then one family with the favored mutation slowly spreading and becoming the dominant family until all the subsequent generations are linked back to this one family and the one individual in who's gametic germ cell the mutation occurred. This is a slow process. Evolution is slow. Because of how slow mutation is, thousands of species are predicted to become extinct due to human caused (anthropogenic) climate change
Variation means that should the environment change, maybe due to climate change, maybe due to war, maybe due to disease.... then some of us might have a few traits that allow us to survive, such as a resistance to that disease. Thus the species will not become extinct
Variation and Natural Selection
Natural selection - starts with variation, followed by selection for favored traits within a population
Those traits come to be the most common, this leads into evolution if the trait becomes spread throughout the whole population or if the population is separated from other related populations due to oceans, mountains, humans etc. Thus you eventually end up with a population that is different from its ancestors - like the Kea and the Kaka
Variation and Evolution
This follows on from Natural Selection
In a particular environment those with particular traits are favored
As the environment changes other traits might be favored
As predators adapt other traits might be favored
Eventually those whos families do not have the favored traits either breed with those that do and thus their descendants will have those traits, or they will die out
Over time there is a very slow race
The predator adapts better hunt its prey, the prey adapts to better hid from the predator, so the predator adapts to better hunt its prey, so the prey adapts to better hid... and so on for thousands of years. Driving evolution, you can only pass on your genes if you survive and survival might be by being the best hunter in your species, or if hunted, then your survival is by being the best at hiding
The better hunter will always kill the worst at hiding and the worse hunter will starve as those that are hidden are to hard to find
Only the strong predators and the strong prey survive to pass on their traits
Only the strong survive
Only the fittest pass on their genes
And the offspring are those that whos parents survived to a reproductive age
The offspring are the offspring of the winners of life's fight for survival