Sam (13) asked “What are the building blocks of cells? And does it vary for each cell?”

Up-dated  24/10/2019

Thank you for your question Sam. As usual I put it to a member of my team. Lets see what they say and then, maybe, I can add to it.

Thank you for that team. Cells are obviously very, very important. We, and all, living things are all made up of them. But what about the cells themselves …what are they made of ? A little research shows that all cells contain  proteins, lipids, carbohydrates and nucleic acids. Let’s look at the role of each of these groups of compounds.

Proteins are all important (they are made of things called amino acids BUT enough of that). Proteins have important roles in cells. They provide the cell with energy, they fight infections they help move other components  around the cell.

Lipids are basically fats and therefore are a source of energy. The proteins will access the lipids to help them in their tasks and the Carbohydrates are another source of energy

Nucleic acids are better known as amino acids that make up  RNA and DNA structures. These are probably the most important, ………no I am wrong, the nucleic acid component of the cell needs all the other components to survive. They will not last long if left alone. The nucleic acids are the messengers of the cells. In simple terms they have, in their structure , the message that enables the construction of a living thing (animal, plant) from the activity of the rest of the cell. You could say they are the managers.

A little addition ……. what is an amino acid? Firstly as an acid it contains the -COOH group of atoms. CH3COOH is a familiar acid

Shown here in its structural form

known as acetic acid (vinegar).

Amino acids basically contain NH2 groups instead of CH3 . One of the simplest is glycine.

Proteins also (in some cases) act as catalysts (something that enables a reaction to occur. In these situations they are called enzymes.

I really hope this is helpful. Thanks for the question.

Luisa 9 asks “How did the first humans appear?”

Thank you Luisa for your second question.  Here are my friends thoughts about how humans appeared.

Thanks team, Luisa let me add some more details.

My friends are correct, it is thought that the first life appeared millions of years ago. The life that formed was not at all like the animals and plants that we see around today. It was very, very small. So small that we would have needed a microscope to see it.  Over the next thousands of years that life changed (we say it evolved) and it reproduced. Sometimes when it reproduced mistakes were made and bigger forms of life were formed. Eventually a mistake in the reproduction led to the first plant (a moss) being formed.

Over the next thousands of years further mistakes were made and  the first animal was born. From then onwards the evolution of animals and plants continued…….UNTIL …..again many thousands of years ago the first apes evolved. The apes continued to have babies and further mistakes were made …… the baby apes walked upright, their brains were bigger, they had less hair, all small changes but over thousands of years small changes can become big changes. The result was that humans were formed and you, me and everybody else are the result.

Things haven’t stopped ….changes (evolution) continues …..we might be very different in many thousands of years time.

Hope this helps. Not happy about something, then ask another question.

“What does “eco” in ecosystem mean?” asks Austin (8)

I will just add a few words myself. Thanks for your input.

I like the idea of an ant’s nest being an example of an ecosystem. The nest is ‘everything’ it’s a home, a place to live and to work from, a creche for baby ants, a food store, a food production place, a protective environment, maybe an ant hospital, and lot’s more. It is an ecosystem.

The word ‘eco’ also combines with ‘logy to form ‘ecology’. This is like the word ‘bio’ combining with ‘logy’ to form ‘biology’.  The word ‘logy’ is a word which originally described lots of learning.

I will stop now. For an eight year old I think everything gets very complicated. I very much like the ant’s nest described as an ecosystem.Maybe you could let me know of other ecosystems?

STOP

Hayley (11) asks “Were unicorns ever real????”

Thanks for the question Hayley. My friends are back from their holiday so I asked them ….this is their answer.

The fact that there are no fossils does not mean that unicorns never existed. If you look at how modern humans evolved (changed) from apes there are a lot of gaps in our understanding, which could be linked to fossils that have not yet been found.

Where fossils have been found we can get lots and lots of information from them especially from the age of the rock in which they are found. This is to do with something called radioactive decay. This allows the fossils to be placed fairly accurately on the ‘evolution table’.

Evolution is the change in the inherited characteristics of  populations of living things over successive generations. Evolutionary processes give rise to diversity at every level of the population. For example a pair of monkeys might give birth to an albino (white) baby. If that baby, when it is older, gives birth to an albino baby, we could call that an evolutionary change which might, in a few thousand years create a whole population of albino monkeys.

I have two immediate thoughts about unicorns. Firstly they are completely made up and secondly they are a brief part of an evolutionary  story that didn’t survive. For example an animal (horse, deer, goat or other animal) was born with one horn by some biological accident, it lived but it’s children were ‘normal’ so the trait ended.

I prefer the mythical, made up model. I would like your thoughts.

 

Destiny (10) asks “Did/are unicorns real?”

Destiny, thanks for this second question. Interestingly it has connections to your previous question about evolution.

I asked my friends about unicorns.

The fact that there are no fossils does not mean that unicorns never existed. If you look at how modern humans evolved from apes there are a lot of gaps in our understanding, which could be linked to fossils that have not yet been found.

Where fossils have been found we can get lots and lots of information from them especially from the age of the rock in which they are found. This is to do with something called radioactive decay. This allows the fossils to be placed fairly accurately on the ‘evolution table’.

I have two immediate thoughts about unicorns. Firstly they are completely made up and secondly they are a brief part of an evolutionary story that didn’t survive. For example an animal (horse, deer, goat or other animal) was born with one horn by some biological accident, it lived but it’s children were ‘normal’ so the trait ended.

I prefer the mythical, made up model. I would like your thoughts.

“Did humans evolve from monkeys?!?!” asks Destiny (10)

A great question Destiny and a difficult one to answer. You use the word ‘evolve’ in your question. I think we should spend the first part of a possible answer looking at that word – ‘evolve’. I thought I would ask my friends about this. Let’s see what they come up with ….

It was Darwin, a famous scientist, who proposed that all living things over time are slowly evolving. So another thing we have to think about is time. 

Life on our planet is thought to have been created four and a half billion years ago. That is 4,500,000,000 years ago. That give a lot of time for something to happen (evolve)  gradually.

Scientist think that ALL living things on our planet started 4.0 billion years ago with the formation of the first micro-organism that could reproduce itself. It was no bigger than a pinhead.

Below is a crude timeline which illustrates  how different life forms evolved (developed) over those millions and millions of years from that pinhead.


So Destiny, we have evolved from the primates but the primates evolved from other living things, and it started 4.0 billion years ago from that pinhead

I think the crucial factor in understanding this in the time span …which is unbelievable to us who live for such a short part of the story.

Unhappy about this, then please write a comment or ask another question.

(rewritten June 5th 2018 )

Chris (10) asks “How can you correctly determine the age of a tortoise or turtle?”

Chris thank you for your question. Some people suggest that it is the number of scutes (the bony rings that the tortoise has on its shell. However look at this baby tortoise breaking out of it’s shell.

Here he/she is and already there is more than one scute. Maybe we need to take a hint from a tree. How do you find the age of a tree. When you cut a tree down you can see inside of the bark a series of rings. (You can obviously do this without chopping the tree down).  Look at the image below.

The scutes of a tortoise also have rings. The image below is an ‘old’ tortoise.

This image is of a very young tortoise

Maybe these will give you a clue about the tortoises age. It is thought that this could be a rough age indicator.

Alternatively you could get a size chart, however, like the rings it is difficult to accurately determine the age of a tortoise. Maybe the only true way is to know when it was born.

Charlie (10) asked “How many people live on earth”

Charlie ….. a simple answer …about 7.6 billion people.  That is a big big number 7, 600,000,000. A lot of people and it all started about 2.5 million (2,500,000) years ago.

The people then where very  olde worlde and didn’t look very much like us today. They were wanderers and spent a lot of time hunting and gathering food.

This species ( a word to describe a group of animals that are alike) was  the homo species and we are derived from the homo sapien group. There were then quite a lot of different homo people, however we were the only group to survive.

Below is a drawing of the what the homo family might have looked like. Can you find the homo sapien?

“Why do spiders make webs and what are they made of?” asks Emily (7)

 

Thanks Team and thank you Emily. My first thoughts are about catching a spider and trying to keep it at home or somewhere else or finding a spider in the wild so that you can see it making, or looking after its web. I am however reluctant to suggest both catching a spider or keeping it in an indoors.

In some countries spiders can be dangerous so please do not interfere with it until an adult has identified it and  said that it is OK to collect it, or observe it closely.  If, with an adults permission, you can keep a spider then a large plastic aquarium would probably provide a good home for it.

A spider’s web is made of a type of silk, so ask an adult if they could find some silk for you to investigate. Maybe you could use it to make a web and see how strong it is?

If you do keep a spider, at home, or in the classroom you will have to decide how you will feed it. That will be an interesting investigation.

Look at this video of a garden spider building its web. In the first part of the video everything is slowed down. In the second part of the video things are at the real speed of web building.

“I have a question about Hermann’s tortoises” says Christopher (10)

Many thanks team. The Western Hermann’s tortoise has evolved in the warmer parts of Europe while the Eastern Hermann’s tortoise has evolved in the colder parts of Europe where the ice age lasted longer. The Eastern tortoise is bigger than the Western one and it has been determined that it probably evolved faster than the Western tortoise. They can be distinguished by their carapace and plastron patterns. The images below are from Chris Leone
The Plastron

The Carapace

Maybe, Christopher you could tell me how long tortoises live? All you need to do is tell me in the Reply box below.?

Many thanks to
Chris Leone for his images
Changes to title, images  and added information on tortoises (21/11/17)