WHEN DID HUMANS FIRST START WEARING CLOTHES?

 Ever wondered what cool sciencey stuff they are teaching undergraduates at the University of Queensland?


 Every school day I will post my newly learned cool fact... Enjoy 

14/03/2013

GENETICS

WHEN DID HUMANS FIRST START WEARING CLOTHES?

Genetic research shows that anatomically modern humans (AMH) appeared around 200,000 years ago.. It is extremely likely that they out competed their more primitive hominid cousins in other climates due to a series of technological advances and complex behaviours.

One of which was the development of clothing.

Clothing allowed humans to live in colder climates as they were protected from cold related body stress. This meant that they could live higher latitudes. And it also meant that they could survive colder glaciation periods.

 So when did humans first start wearing clothes?

 

Archaeologists first started to answer this question from physical evidence. Firstly, they found eyed needles for clothes production. These needles, made of bone, first appeared around 40,000 years ago. But this signals the arrival of complex clothing, not the start of it. 

One archeologist wrote “it would be unlikely that complex needles and thread arouse simultaneously with clothing use”.

So they could say with certainty that we had clothes from this 40,000 year ago point. 

There is also physical evidence of hide scraping tools, but these are from over 780,000 years ago. 

Hides can be used for many different things, shelter construction, carrying bags. Not necessarily clothes

Despite these hide scrapping tools, it seems likely that modern humans outcompeted previous species of homonym because of our use of clothing. And AMH did not appear until around 200,000 years ago.

This confusing and conflicting information was all that was available to answer the question till within the last decade. Indeed it has been as recently as the last few years the puzzle has been put together by genetic evidence.

And this has come from an unlikely source:

Parasites often provide an extremely valuable look into the genetic history of their hosts and humans are no different. 

Investigating from the genetic variation of the different types of lice that attack humans we can deduce some amazing things. 

Firstly, we can look at the divergence of genetic history between head lice and pubic lice. From genetic research done earlier in the previous decade,  we can see that head lice diverged genetically from pubic lice between 1.2 Million Years ago and 3 Million Years ago.

So we can deduce, that it was during this time that homonyms started to lose their body hair. 

The head louse is now a very different species from the Pubic dwelling cousin. 

As hair coverage on homonyms reduced to the very top of the head, the head louse became more and more specialised for living on in our hair.

However, the clothing louse diverged genetically from the head louse only very recently. 

Due to the nature of human development it is extremely unlikely that a divergence from its lineage would have been caused by anything other than the presence of clothing as a biological niche for the louse to fill. As Toups, Kitchen, Light & Reed,( 2011) put it “… determining when head and clothing lice began to diverge provides a date by which clothing must have been in regular use by humans.”

Basically scientists have taken elements from the head louse DNA and elements from the clothing lice DNA and analysed its genes sequences. They were looking for these Genes  

-              COI

-              18s RDNA

-              EF – 1(alpha)

-              RPII

Basically they took these genes from the lice and compared them to see the differences. The result of this genetic research was consistent with known human development. 

For example, (interestingly) the results showed that all head lice seem to have come from a population size of around 0.934X10+6, which is a considerable bottleneck for these tiny little insects. In other words we were that close to eliminating them. 

This would have been the result of body hair loss to the top of the head, not active human attempts. Post bottleneck stage shows, that a significant proportion of this small population becomes part of the divergence into clothing lice. 

This is perhaps a representation of how quickly the lice filled the new niche. Now for the part I’m sure you have all been waiting for.

Using this new latest study, when did humans start wearing clothes?

Well, as you can see from this graph there are the major events in human development, estimated time of body hair loss, first evidence of hide scrapers, first evidence of tailored clothing (the bone needle) etc.

The grey line shows the likelihood that the lice had genetically diverged into a new population. 

From the collective research of the genetics the median head louse clothing divergence is at  170,000 years ago.

 And the red area is the presence of a glaciation period where mean world temperature would have dropped.

This is all consistent evidence that supports the statement.

So...

 

Thanks to genetic research of parasites we are able to state that it is most likely that humans were wearing clothing around 170,000 years ago.

DOWN SYNDROME

Ever wondered what cool sciencey stuff they are teaching undergraduates at the University of Queensland?

 Every school day I will post my newly learned cool fact... Enjoy 

11/03/2013

BIOLOGY

DOWN SYNDROME

For every child born, around 1 in 650 will be born with Down Syndrome.

This is extremely common for a genetic disorder.

We all know what Down syndrome is; we have all met someone with the condition. Yet it is very rare that it is understood outside of families who have not had to deal with a loved one with the syndrome.

Down syndrome is caused when the copying of a chromosome is done incorrectly.

To understand this we need to understand cell division.

In stage one of cell division known as Prophase. The Nucleus DNA condenses into long strings tightly bounded together.

In stage two known as Prometaphase the nucleus DNA is completely bounded together. The nuclear membrane breaks apart and long strings begin to grow into it and attach to the tightly bound DNA.

In stage three known as metaphase the tightly packed DNA now called chromosomes aligned along an imaginary line in the middle of the nucleus.

In stage four called the Anaphase, the long strings attach to the chromosomes, then pull them apart.

In Telophase the chromosomes form into a ball and a cell wall builds around them. The cell also splits into two and cell division is complete.

If you can understand and remember that, then you should sign up to do a biology degree at your nearest university.

 

Down Syndrome is caused when cells divide incorrectly in the early stages of our development. When we are nothing more than a blob of cells in your mother’s womb, the cells that male up all of you are dividing. So if they make a mistake, it can spread.

Down Syndrome is having too many genes of what is known as gene 21. When the cells are in Anaphase the split is not done evenly and gene 21 becomes too pronounced. 

Usually when a cell does something like this it self-destructs and doesn’t cause any damage. Something about this particular gene however, causes the cell to continue and we get the sydrome to be expressed.

Research continues…

PLANTS AND SPERM?

Ever wondered what cool sciencey stuff they are teaching undergraduates at the University of Queensland?

 Every school day I will post my newly learned cool fact... Enjoy 

11/03/2013

BIOLOGY

PLANTS AND SPERM

I guess in this day and age it is common knowledge that male animals produce sperm and female animals produce eggs.

But what I bet a lot of you didn’t know was that there are indeed male and female plants and they also produce sperm and eggs.

Even moss, one of the simplest and smallest of the plants on earth produce billions of sperm per ace of forest they cover.

Moss is an interesting case too.

It was one of the earliest plants to evolve from algae and has an interesting reproduction cycle.

Animals produce sperm in an aqueous solution for delivery to the female egg,

Moss doesn’t. It produces raw sperm.

It needs a coating of water between the male plants to the female plants for the sperm to swim between. This is why moss will only grow in a very moist environment. Its reproduction cycle is basically aquatic.

Moss will continue to live on a dry rock, but it won’t be able to spread.

As soon as moisture hits such a dried out moss plant, it is open season and all sexual activity springs into life.

Just remember as you trek through the forest, the damp rock faces are probably seething with moss sperm.

CELL DIVISION: WHERE DOES CANCER START?

Ever wondered what cool sciencey stuff they are teaching undergraduates at the University of Queensland?

 Every school day I will post my newly learned cool fact... Enjoy 

11/03/2013

BIOLOGY

CELL DIVISION: WHERE DOES CANCER START?

Like so many of the beautiful things in our universe, cells have a life cycle.

Their existence begins with a new beginning, they grow into maturity and then they fade away and die.

Life Cycle of a Star

In humans, some cells continue to grow and divide for the rest of your life (skin cells), while others will grow only when they need to from an injury (liver cells), while others never regrow (muscle and nerve cells).

Life Cycle of a Frog

But all follow this cycle of birth, growth and then death.

Life Cycle of a Cell

Except for one type of cell.

This type of cell has a name that we all know and fear.

A name that undoubtedly has touched every human on this planet.

Cancer…

The life cycle of cells is controlled by an extremely complex set of checks and balances that allow the cell to progress to the next stage of its life cycle. These checks and balances also stop the cell from staying in the wrong sequence.

If even one of these balances is wrong then the cell can malfunction.

Never the less, even when this function is broken, the cell usually sends out a distress signal that causes special proteins to immediately cause it to self-destruct before it can cause any damage.

It takes a special type of malfunction that causes the cell to not only get stuck in a particular life cycle, but also for it to not send out the signal for help.

It takes an even more special kind of malfunction for a cell to get stuck in a life cycle where the order of the cell is to reproduce, for all of its offspring to reproduce and this to process to never stop.

And finally, it takes the ultimate kind of malfunction to occur where all of this happens and the cells can spread to anywhere in the body and continue to grow.

This type of cell is called a malignant cancer.

While this horror is truly a scourge on humanity there is, as always, opportunities amongst the disaster.

Even the most prolific of normal cell types can only divide twenty to twenty five times before they themselves die.

Cancer cells never die.

There have been some cancer cells extracted from a woman in the fifties that are still growing in a lab to this day.

It seems that as long as they are supplied with nutrients they will continue to grow forever, they are considered immortal.

If we could harness this amazing longevity power perhaps we could create cells that work normally but never die…

Cancer also provides a glimpse into the workings of cells. How the different parts that make it up work together to create life…

But realistically, there is no silver lining with cancer.

The horrible truth is that we don’t really know enough about how cells work and how the mutations that cause cancer start.

We know risk factors and that’s about it.

Research continues, and in the interim millions will die from this scourge.

The growth towards personalised medicine continues to be a beacon of hope for many. As specially tailored drugs are built for specific personalised cancers, but that story is for another day.