Olivia+M.

The Science of Sleep //[Systems?? I don't know?][Post #3][13/01/16] // People spend about 25 to 26 years of their lives sleeping.

Sleep used to be considered an inactive state, but in the 1920s, recordings known as electroencephalograms (EEGs) showed that sleep is an extremely active state of mind. EEGs revealed that there are two types of sleep: REM (rapid eye movement) and NREM (non-rapid eye movement). The two alternate in the sleep cycle through the night.

//[The sleep cycle]//


 * REM Sleep**
 * The brain is even more active than when we are awake, even though we aren't conscious, increased by around 20%.
 * This is the period when most dreams occur, and when people wake up from this state they are more likely to remember their dreams.
 * Eyes dart around under the lids (giving REM sleep its name), the middle ear muscles move
 * Breathing rate and blood pressure rise.
 * Arms and legs are effectively paralyzed. (Stops people from moving when dreaming)
 * A person is usually difficult to rouse, yet we usually wake up from REM sleep in the morning
 * Occurs 3-5 times per night. First is about 70 to 90 minutes after we fall asleep.

//[REM eye movement]//


 * NREM Sleep**


 * ** Stage One: ** People are half awake and half asleep. Muscles relax and we can be easily woken up.
 * ** Stage Two ** : Within ten minutes of light sleep, the breathing pattern and heart rate start to slow down. Lasts about 20 minutes.
 * ** Stage Three ** : The brain begins to produce delta waves. Breathing and heart rate are at as low levels as they get.
 * ** Stage Four: ** Rythmic breathing, limited muscle activity. This is when things like night terrors or sleepwalking occur.

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The amount of time people need to sleep varies from person to person, but on average it is 7-8 hours. It varies from between 5 to 11 hours. Animals require average amounts of sleep, too. A python gets about 18 hours average, and a chimpanzee gets about 10, for example.
 * How Much Sleep Do We Need?**

//[A giraffe only needs around 1.9 hours of sleep per day]//

Brain waves are electrical pulses in the brain. The five main brain waves we produce are alpha, beta, delta, theta, and gamma. // (Five brain waves abd Hz levels) //
 * Brain Waves**
 * ** Gamma Waves ** : fastest brain waves, high frequency. Processing of information.
 * ** Beta Waves: ** waves of alertness and attention, normal waking state of consciousness. Cognitive tasks.
 * ** Alpha Waves ** : waves of relaxation. Found during quiet and resting states.
 * ** Theta Waves ** : waves of light sleep/drowsiness. Learning and memory related.
 * ** Delta Waves ** : found during deep sleep. Slow waves. Heart rate and blood pressure fall, brain temperature cools down.

Sources: [|The Science of Sleep: What is Sleep] [|What Are Brainwaves] [|Natural Patterns of Sleep] [|Healthy Sleep: Recharging Your Batteries]

Further Reading: [|More on Brain Waves] [|Sleep Self Assessment] [|Animal Sleep & Connection to Humans] [|How Much Sleep Do You Really Need?]

The Evolution and Domestication of Cats

 * //[Evolution][Post #2][19/11/15]//**
 * //All cats come from reptiles.//**

//[A potential drawing/diagram of a pseudalurus]// The most recent ancestor of all cat families was the pseudaelurus. This prehistoric cat lived in Eurasia and North America about 20 million years ago. It had a weasel like form. The pseudaelurus died out approximately 8 million years ago. It's predecessor, the proailurus is debated as either the first true felid or just as a subspecies. It lived in Eurasia roughly 25 million years ago. It's tail indicates that it may have hung from trees and it was slightly bigger than a domestic cat.

[[image:post 2 pic 1.jpg width="402" height="269"]]
//[Yep. A lion. That's part of the panthera family.] // Cats of all shapes and sizes are classified by scientists as part of the Felidae family. Within this family, domestic cats are one of the most recent to have evolved. The family is split into three different categories: With the exception of lions, all cats are mostly solitary creatures and with the same exception of lions, where males have a large mane, it is difficult to tell male from female besides a slight size difference. Cats have a large variety of different coat colours that evolved depending on camouflage with their surroundings.
 * Panthera (any cat that roars; lions, tigers, leopards)
 * Acinonyx (the Cheetah, the only cat whose claws aren't retractable)
 * Felis (any other cat)

//[An ancient Egyptian cat statue]// Most people believe cats to have been domesticated about 3, 600 years ago by the Egyptians. Paintings and inscriptions of cats from this time period indicate that cats were domesticated to an extent around this time (though the cat isn't completely domesticated and retains a lot of it's more 'wild' tendencies) and living with humans. They were very important to their religion and even had their own cemeteries or were mummified. There is even older evidence of cats in relation to humans in the Fertile Crescent about 9, 500 years ago in the form of a cat's remains buried with a human's in Cyprus.

//[A domestic cat]// Most animals that were domesticated by humans had very obvious reasons, such as for food or cows for milk, or dogs for security reasons. Dogs also were already pack animals where the human would've taken the place of the leader, making things simpler. Cats, however, don't have an immediate, obvious use, and were also solitary creatures. About 5, 500 years ago, there was an agricultural boom in China. It wouldn't have been the first farming there, but that was when it became really successful. They would have grain and food stores which would attract mice. Their population would swell in these areas. This would attract smaller, more tame and less fearing of humans wild cats. It's assumed that humans would have seen the mutual benefit in keeping cats around as mousers in their farms, and probably they just tolerated them and gave them a warm place to stay. From there, the benefit of cats as a pet would grow, for example, Europeans would much later take them on ships to hunt the rats. Unfortunately, there isn't much proof of the way cats were domesticated.

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http://pets.thenest.com/animal-did-cats-evolve-from-5250.html http://icatcare.org/advice/cat-care/origins-cats http://www.theatlantic.com/technology/archive/2013/12/how-humans-created-cats/282391/ http://www.provet.co.uk/cats/evolution%20of%20the%20cat.htm
 * Sources**

[|About the Pseudaelurus] [|Are Cats Domesticated?] [|Evolution and Domestication of Cats] [|The Genes Behind It]
 * Further Reading**

Genetically Modified Micropigs
// [Genetics, Post #1][22/10/2015] // Yeah. Micropigs. For pets.

Micropigs previously existed by breeding dwarf pigs and runts to create "teacup pigs" (which stay small for a time before growing anyway) but now a group of Chinese scientists genetically modified Bama pigs into a miniature version. They were originally created with the purpose of being more convenient for research in labs because the smaller they were, the more manageable they would be and the less they would cost to maintain. Pigs are one of the best animals for research into human health because of the similarities in tissue and organs. In particular, they plan to study Laron Syndrome, which causes dwarfism. Now, the team is selling them as pets, for 10,000 yuan, which is about 1600 US dollars, which they say they will use to fund their research. They say they hope to allow people to order custom coat colours and patterns as well, with further gene editing.

//[TALENs diagram]// CRISPR/Cas9 is a technique that makes gene editing incredibly easy, causing it to fill up the biology world. This team of researchers instead used a technique called TALENs (Transcription Activator-Like Effector Genome Editing). TALENs instead can target a specific gene and disable it, which they did to one of the two copies of the growth hormone receptor gene in cloned male Bama pig fetuses. Without this, these pigs do not receive signals to grow.

//[Showcase of micropig at summit]// These male cloned Bama pigs were born stunted, and grew to be about 15 kilograms when mature. Rather than risk potential health issues with cloning, the scientists bred the male micropigs with regular female pigs. The results of this were that 50% of the piglets were born micropigs. BGI (the Chinese research facility) says they have noted no health probles in the second-generation micropigs.

//[BGI technician holding micropig]// There is a Some people consider micropigs to be a negative thing for the world, thinking that it will distract from other research or that to edit genes for the purpose of creating pets is superficial or immoral. Others say that genetically modifying pets is the same as breeding for traits in animals, except that it is done much faster.

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[|BGI's Site] [|TALENs and CRISPR/Cas9 Information] [|More on Micropigs] [|On Gene Editing Techniques]
 * Further Reading**

http://www.nature.com/news/gene-edited-micropigs-to-be-sold-as-pets-at-chinese-institute-1.18448 http://www.cnet.com/news/genetically-engineered-micropigs-to-be-sold-as-pets-yes-micropigs/ http://www.iflscience.com/plants-and-animals/scientists-genetically-engineer-micropigs-sell-pets http://www.businessinsider.com/chinese-genetically-engineered-mini-pigs-2015-9
 * References**