Punnett Squares

Let's take a square, and let's split it into quadrants. Let's use eye colour for this example, and put two brown uppercase B's in the top left and right, and then put an uppercase B, and a blue lowercase b, in the bottom two squares.

Since we put them as uppercase the two uppercase B's are the more dominant trait, and the small blue lowercase b's are the recessive trait.

So the chances that a child between these parents (uppercase b's) has a 50% chance to have a child that has brown eyes, but a 0% for a child to have blue eyes, keep in mind the uppercase B's are Genotypes, while the lowercase blue b's are Phenotypes.

Now, let's cross two parent flowers, one red, and one white, and when you combine the red and white alleles, you get... Pink. This is blending, it's a mixture of the two colours, and the traits that both parent flowers have, and they are both incompletely dominant, so they blend instead of having one or the other. 

Now let's try blood types, let's pick three for this example: A, B and O blood types, Let's say one parent has an AB blood type, meaning they have both A and B types, and they do not blend as they are both dominant alleles. And are co-dominant

Let's say another parent has an A blood type, and their phenotype is an A blood type, and their genotype is an O blood type. This is interesting about blood types as O is recessive, while both A and B blood types are co-dominant.

All the combinations are as follows: AA which means that you have only A blood alleles, AB meaning you have both A and B alleles and are co-dominant,
AO and BO blood types are still going to be A blood types because the O allele is recessive. So there's roughly a 50% chance to get a A blood type.
So if you want yourself to be a O blood type, both of your parents must carry a O blood type.

Physics pt. 12: Analog vs Digital signals

 Analog is trying to reproduce the signal of what is happening, think changing a piano piece, to a guitar tab, it's the same, but different.

A digital signal turns sound to ones and zeros to then does its best to reproduce the original sound, think chiptune music, and 8-bit audio.

The problem with analogue signals is interference, let's take a number, 24 in this case and let's make it analogue, if you were to take the 24th signal, if it were to be analogue, it would not be straight, as it would be a wavy line, and it may not look like a 24 because it would fluctuate.

But if you were to take a digital signal, that 24, will always be a 24, and never go higher or lower, and not fluctuate either. That's why when you listen to guitar it sounds more bouncy, while listening to more chiptune music it will sound more robotic and less genuine.

Talking is an analogue signal, and when you add words, you are "encoding" the signal with words,  

Chemistry pt. 6: Ionization energy trends

Ionization energy is energy to required to remove the highest energy electron from an atom.

If you go down a group, removing the highest energy electron becomes easier, or ionization energy decreases the further you go down.
And if you go from left to right on the periodic table, the energy that is necessary to remove the election increases.

History pt 4: The Neolithic Revolution and early agriculture

The periods humans today use as a scale follow the discoveries of tools found during archaeology.
So, most pre-human or near pre-human period is the Palaeolithic period, or the Old Stone Age, which is a significant part of human history.

Then there's the Mesolithic era which was around 15,000 years ago. And those stones were smoother than the ones from the Palaeolithic era, then 10,000 years ago stones were more polished and had a smoother look to them so we named this period the Neolithic period.

The most important innovation in human history would be agriculture, around 10,000 - 15,000 years ago, humans would have to travel and migrate to follow food sources.
Then Neolithic humans came up with the idea of agriculture, we started domesticating animals, breeding them, raising them for milk and meat, and we started planting vegetables nearer to their homes. And this helped with being less nomad-like.

Our estimate was that the world carrying capacity of the earth for humans when we were hunter-gatherers was a population of 10 million,
around the time of the last ice age. It is because a tribe of 100 hunter-gatherers needed around 50-100 square kilometres of forage land to gather enough food to supply the whole group because you would have to walk many kilometres a day to gather enough. 
So having a larger place to forage increases the chances of you getting more food. 

The creation of agriculture, allowed a much larger population density because most of the food is easily accessible, and after agriculture, the carrying capacity of the earth was 250 million, 25 times more than before agriculture.
Because of the Romans, we know that in 2000, years after agriculture was founded, the earth's population increased to nearly 28x.  And that growth increased to the current population of 7 billion. And without agriculture, we would not be able to have this many people on Earth.

One theory is that agriculture happened a couple thousand years after the ice age, it allowed land to be arable (meaning can support plants), and able to support agriculture, but then what about the other ages when we weren't in an ice age.

Another theory is that anatomically accurate humans only appeared 200,000 years ago. And maybe they didn't have enough brainpower to learn to grow plants.

Another theory is that after the human population got too much for the groups of hunter-gatherers to be able to survive. The theory states that maybe for every human born, another would not have enough to survive, since there was a limited amount of food. And maybe a tribe of humans said let's try planting some plants near their homes and domesticating out of necessity. And after they started doing that, their population density increased.

Anyway, since agriculture was being learned and used by humans, we were becoming less nomadic, and since we could settle down and stay in a location nearly for as long as we lived, we started to become more protective, by building defences,
and instead of the men and women out gathering food for the village, they could just have a few people working in the fields while the other people maybe constructed housing, and crafted weapons for war. 
Not only they would be able to have a bigger population, meaning more warriors to fight if they were to be attacked, but instead of patrolling a large area of land, they would only have to worry about their "property", since their property was their fields meant for growing and cattle grazing.
While hunters and gathers might treat the land they roam as their territory.

Whoever invented agriculture, it had a massive impact on our societies as without it, agriculture paved the way for large civilizations that could not exist purely on hunter-gatherers. As our modern civilization would not continue due to needing agriculture to thrive. As most of us would not be around without the food that agriculture, and technological advancements that followed.

Most believe that agriculture came from multiple different places, and spread like wildfire, mostly from the modern-day Middle East: Syria, Palestine, Iraq, and Southern Turkiye.
We believe that agriculture started here, around 10,000-15,000 years ago. We believe that rice came from China, with estimates of 6000-13,000 years ago, the Potato coming from the Andes mountains.

And the time frame, of 15,000 to 20,000 years ago might jump back a few thousand years in the future as we might discover new and exciting evidence that anatomically accurate humans appeared many centuries ago.

For most of human history, not only we were making tools and weapons from jagged sharp stones, but also chasing animals around looking for food, and having an unreliable food source to feed our family.

 

Physics pt. 11: Digital and analog information

 Something analogue can be any value within a given range, and something digital can have multiple discrete and different levels, an analogue clock has hands which move around the centre and since it's analogue you can make it so that it displays certain numbers (10:30, 11:31, 5,03) and so on and it has infinite values.
A digital clock can do 10:30 and 10:30:51, which is more precise, but they have a finite number of values.

Sound is not only a wave, but it is an analogue, the amplitude, the volume, and the frequency we hear as pitch are all infinite possible combinations.

The first recording of sound was imprinted on a material, like a vinyl record, cassette tape, or a music box, which sound is imprinted on a surface or material. 

But the thing about recording on such surfaces is that if you smudge a cassette tape, or scratch a vinyl record, that recording will deform the recorded sound waves and thus, cannot reproduce the sound that was recorded before the cassette, or vinyl damage.

Eventually, soundwaves were digitized, so how this was done the analog inputs were assigned numbers

2:28 14mins

Physics pt. 10: Absorption and Reflection

Light can interact with many things, Absorption and Reflection.
If you were to be in the mountains and take a look at a clear pond, you would be able to see the surrounding mountains which are reflected off the water causing it to reflect the light.

And the same with snow, if you were to look straight at the snow, it would hurt your eyes, because it is very reflective and can blind you. That's when people are in he snow for a long time, they have to wear spectacles so they don't get blinded. And why some ski masks have tinting to help.

Alleles and genes

 Imagine the DNA being a sort of string (it's actually a sort of double helix, but imagine a string to make it easier).

Different parts of this string can be coded for different proteins, let's say that a certain part of this string is coded for DNA replication and another part for the pigmentation of your eyes. 

The most primitive life ever found was self-replicating RNA.

Chemistry pt. 5: The Lewis diagram

The Luwis diagram is similar to the Bohr model as it is a simplified Bohr model, so let's take a Nitrogen atom, it has 5 valence electrons, 7 total elections but 5 valence. So to draw a Lewis diagram for a Nitrogen atom, you would just draw the Valence elections, without the rings,.

Now let's take a Nitride Ion, which is a nitride atom that gained 3 elections, so a nitride atom has 8 valence electrons,
if we were to draw a nitride ion with the 8 valences it would be an N with 8 dots around it,
and those dots being the Valence elections, now since it added 3 elections, it is now a negative 3 charge, and you would write an N with 8 dots around it, but because it is a negatively charged ion, it would have brackets with -3 outside it.

Introduction to heredity

 Heredity is inherited from traits from parents.

Some traits seem to dominate, like skin colour, hair colour, and height. 
The study of what gets passed on via genes was much, much older than the study of DNA.
The father of heredity study is Gregor Mendel who was actually a monk and he would experiment with plants and see which plant would follow which parent DNA more.

Certain traits are more prominent than others. An Allele and a Gene are very different and have defining characteristics for both, Gregor mentally was doing this in the 1850s.

Let's take two random chromosomes from the father, and mother, and on the chromosomes is a Locus, which is where the gene for the eye colour comes from, and let's say these are Homologous chromosomes, so they code for the same allele.
Now if both parents have different eye colours the person would be a heterozygote. Which is a heterozygous genotype. If both parents have the same eye colour of genes the person is a  homozygous, or this a homozygous genotype.

But Mendel discovered and learned something we will call dominance, this refers to one of the traits inherited from the mother or father is the more dominant gene. Now let's take two genes: One having blue eyes (the more dominant gene), and the other having brown eyes (the recessive gene).
And since brown eyes are the dominant gene, most of the people who have both genes will most commonly have brown eyes, which is named a Genotype.

Now a Phenotype, for example, let's say you have a brown eye allele from both parents. You will see that you will have brown eyes.

Apoptosis

The word Apoptosis comes from Greek: Apo meaning "Away" and Ptosis meaning "Falling".

Literally meaning "Falling Away", which is a type of cell death.
Apoptosis is one of the ways cells die.

One way is Necrosis, a type of death where the cell will swell and explode. This isn't an ideal cell death as when it "explodes" it can damage other cells around it and can cause cells from the immune system that cause inflammation as the immune system cells might believe that those parts from the cell that recently died from necrosis are invading the body and attacking it.
The human body tries its best to avoid necrosis as it usually happens when the body is exposed to a chemical toxin and it causes the cell to die unnaturally.

The other way is Apoptosis which is the less extreme way of cells dying, for example when your hands are forming in your mother's womb, your hand starts out in a sort of paddle, and Apoptosis widdles it down to form your fingers.
Apoptosis is kinda like dissolving the cells.

Another place where Apoptosis shows up is in a tadpole, when a tadpole turns into a frog, the cells use Apoptosis to remove the tail. 

Apoptosis is happening all the time in your body. It is meant to keep the cells from multiplying too much, while not damaging the cells around it. As too many cells can cause cancer.

Also when cells suffer from DNA damage, if they can't fix it by themselves, they undergo Apoptosis. So with Apoptosis, it can save you from cancer. 

Keep in mind that not all cells will die to Apoptosis. Some will die to Necrosis