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)

Brandon S (10) asked “What kinds of alligators are there?

Nice question Brandon. Alligators and Crocodiles belong to the same family called the Crocodilians.

In a question from Kaia my team introduced the idea of ‘species’ and  said that, for example, there are 20,000 species of butterfly which means there are 20,000 different kinds of butterfly. There are however only two different types (species) of alligator – the American Alligator and the Chinese Alligator. Like butterflies they are almost identical the only difference with the alligators is their size.

There is a lot of work that has gone on by scientists to catalogue animals/insects/plants and other living things. For example you are in the family Sapiens and the Species Homo.

Brandon a question for you. Can you spot the differences  between a crocodile and an alligator?  They are in the same family. Try and let me know.

Thank you for your question.

“How many living things are on Earth?” asks Kaia (8)

Thanks team.

If you want a definition of ‘living’please click on the link.

The species  butterfly has  20,000 of the 1 million species in the insect group. At any one time there must be thousands of living Cabbage White butterflies flying around so you have 20,000 different types of butterfly flying around and maybe there are 50,000 of each type living at any one time.  Help. I must admit the calculations are frightening so i cheated and looked at the work of other scientists who say that there are  8 million species and each species has millions of living specimens. 

The homo species (us) has 9 billion living specimens, I suspect the ant population is considerably bigger than that so in answer to your question …. and then think of the number of plants  ….and then the number of bacteria …..there is no believable answer. However somebody has tried and they had difficulty putting all the numbers on their sheet of paper. Sorry Kaia.

If there are other questions which you may have thought of then please fill in the Reply box below or ask another question.  

Revised 17/102017  Numbers on image changed and text rewritten.

Siobhan (11) asks “Do fish sleep?”

Siobhan. You maybe interested in why all animals (ourselves included) sleep. It is in sleep that we make our memories. Our nervous system and brain work because of fantastic cells called neurons. When we feel something, it is the neurons in the nerve system of our hands that send messages to the brain about what we are feeling. When we sleep it is the neurons in our brain that link up and create the memory of that touching experience.

Thanks for the question. If you have any further questions you can make a comment or ask another question.
(Anyone reading this post who wants to ask a question or make a comment please feel free to do so)

“If all living things were in one food chain, what would be at the top?” asks Chelsea and Ashli (10)

Thanks team. I found a nice little revision site on food chains that you might like to try, find it at Food Chain Game.

Now to your question. Firstly it might be a little difficult putting all living things into one food chain. Secondly do you think it would be humans?  Ecologists (They are scientists who specialise in studying the living environment) rank species by their diets using a metric*  called the trophic level scale. Plants, which produce their own food, are given a rank of 1. Herbivores, which eat only plants, are ranked 2. The fiercest of meat-loving predators, such as killer whales, are rated at 5.5. Humans are rated at 2.5 which is the same level as a pig.

If you want to make a comment please use the box below or you could ask another question.

* metric as a noun means a standard scale of measurement so you could call a temperature scale a metric or any other standard scale of measurement a metric.

(Anyone reading this post who wants to ask a question or make a comment please feel free to do so)

(updated 13/9/17 -changed metric to measurement)
(updated 15/9/17 – ‘measurement’ back to ‘metric’ after realising it was the correct word in the context in which it was presented, added addendum explaining it’s use as a noun)