evolution – Dr. How's Science Wows

Why do we lie?

February 16, 2017nao

I watched a great documentary on Netflix* recently all about lying… it is called Dis(honesty): the truth about lies and I would highly recommend it.

It really got me thinking about lying, why do we do it, what would happen if we don’t and is it a uniquely human activity?

First off, we all do it! If you are shaking your head in disagreement, then you’ve just lied too! Sometimes we do it for good reasons, sometimes just to save our skin, but we all lie from time to time. So why do we do it and is it a purely human activity?

We lie for a number of reasons, it may be a little white lie to make someone feel better or it might be a big lie for our own gain, or to save our skin!

Many of the lies we tell are to present a better side of ourselves; make ourselves appear a little nicer, a little smarter, or a little more popular. We don’t often even recognise these lies, we don’t realise we are doing it – we are lying to ourselves!

On a base level, we probably lie because evolution has shown us that it works to our benefit and the benefit of society. As our social connections have developed, so too have our abilities at lying. It is actually a valuable tool to have and brings with it many advantages. Lying is a sign of intelligence and is considered a complex cognitive skill.

Different types of lies and liars

There are different types of lies and different categories of liars! There are the little white lies that we all do, usually for social acceptance or compliance. There are lies of exaggeration, usually of little harm either; and then there are the bigger lies that are often more serious and come with a lot more consequences if found out.

There are also different types of liars. We are all contributors to the pool of common-or-garden, everyday liars, but things get more serious when we look at the compulsive or pathological liar.

Compulsive liars tell lies as the norm, it is an automatic reflex and it takes a lot less effort for them than telling the truth does. Pathological liars tend to take it one step further; they lie for their own gain, with little thought to the consequences of their lies, for either themselves or others.

What happens in our brains when we lie?

Lying is a complex process; in order to do it our brains must focus on two opposing pieces of information at the same time: the truth and the lie. If we want to process or deliver a lie we need to believe that it could be true. The brain has to work much harder to lie than to tell the truth. Activity in the prefrontal cortex (at the front of the brain) has been shown to increase when a person lies. This is the part of the brain involved in decision making, cognitive planning and problem solving.

Usually when we tell a small lie, for personal gain, we feel bad. These emotions of regret and guilt are controlled by a part of the brain called the amygdala. However, the more we lie, the more we desensitize the amygdala so that it produces less of these bad feelings.

Studies on the brains of pathological liars show that they have about 25% more white matter in their prefrontal cortex, suggesting more connections between different parts of the brain. However, they also have about 14% less grey matter, the part that can help rationalise the potential consequences of each lie told.

No man has a good enough memory to be a successful liar- Abraham Lincoln

Do other animals lie?

Yes some do. One famous example that my children love to hear about is of Koko the gorilla. Koko is renowned for her sign language abilities, with an impressive vocabulary of more than 1000 words. Koko has a pet kitten that has come in handy for more than just cuddles and companionship. One day Koko tore a sink from a wall in her enclosure. When her carers returned and asked what happened, Koko signed ‘the cat did it!’

When do we start lying and how often do we do it?

Some scientists believe that we begin the act of deception as young as six months old! This usually starts as fake crying, or smiling, to get attention. At that age we don’t do a very good job (although it is probably quite cute and amusing to watch) and we likely do not do it as a conscious lie.

By the age of two however, we have put in a little more practice and can deliver an outright lie with more commitment and conviction.

Adults are so good at lying that they can often lie even to themselves; on average, adults lie about 10 times a day and we can throw about three lies into a short conversation with a stranger, without even knowing we are doing it.

Are there ways to spot a lie?

Some of us are better liars than others and there is no detection system, including lie detectors, that work for all. However, many of us amateurs give away some tell-tale signs when we are lying, such as…

We make and keep direct eye contact (contrary to common held belief)
We keep our bodies very still, but we may…
jerk our heads a lot
We give more information than is necessary
We touch or cover our mouths with our fingers
We breathe at a more rapid rate
We cover vulnerable parts of our bodies, such as the throat, head or chest

Interestingly, we are better at lying when we lie for altruistic reasons than for our own good and these lies are more difficult to detect.

So that is the low-down on lying, and not a word of a lie 😉

Have you any facts or stories to add? I’d love to hear them, just leave them in the comments below.

*Disclosure: As a member of the Netflix Stream Team I have received a years subscription to Netflix, free of charge, and an Apple TV, for streaming purposes. As part of Netflix Stream Team I will be posting monthly updates on what we are watching and what is on offer. All opinions expressed will be my own.

Mystery Creature Revealed – the Hoatzin

August 1, 2016August 1, 2016nao

Last week’s mystery creature, a very unusual looking bird, was the Hoatzin (Opisthocomus hoazin). Well done to six-year-old David who knew what it was. David is an avid animal lover who currently lives in Singapore.

Image credit: Bill Bouton, Image source: wiki commons.

Hoatzin are very unusal among birds for a variety of reasons and have intrigued scientists since they were first described in 1776, by German zoologist Statius Müller. Here are just some of facts about these amazing creatures.

Hoatzin are herbivores – but most of their diet consists of leaves, which is unique among birds. In order to digest this cellulose rich diet they have a digestive system more similar to cows (and ruminants) than to any other bird.

They have developed very large crops and the leaves they digest are fermented within their digestive systems. This process begins in their crop and is aided by anaerobic bacteria found throughout their guts, which feed on the leaves and help break down the tough cellulose within them.

They digest their food very slowly and are often seen sitting around, appearing to do very little at all.

The development of their large crop to aid digestion comes at a price; these birds have little space left in their chest and their breast-bones are very simple. Their pectoral muscles are small and weak. These are the muscles that power flight, so these birds are poor flyers and appear quite awkward and ungainly.

There is one other thing about their diet and digestion that makes these birds very distinctive, it is their smell! They are often referred to as Stink Birds, as the fermentation of leaves does not create an odour that humans find attractive. Because of this foul smell, people have no wish to eat them so they are not hunted. Sometimes it pays to be smelly!

Hoatzin live very social lives, often found in large flocks of up to 40 birds. They are found in the rainforests of the Amazon – usually in trees along a river or beside a lake or some other water source. They are very vocal birds with a variety of sounds from calls, to hisses, grunts and croaks.

The appearance of the Hoatzin is very striking and gives them the reputation as a ‘pre-historic’ bird. They have bright blue faces with dark red eyes. They have a strip of long feathers on their head, a crest, giving them a mohawk-type feature. They belong to the family called Opisthocomidae which comes from the greek for ‘have long hair behind‘ – referring to these mohawk styles.

Hoatzin are so unique among bird that they are the only species in this Opisthocomidae family.

The chicks of these birds have claws on their wings (wich disappear after about three months). If the nest is threatened the chicks will often flee and hide, they are even able to escape to the water if necessary and are good underwater swimmers. Once the coast is clear they will use their clawed wings to help them climb back up a tree, to the nest.

Based on their dinosaur-like appearance, and the wing claw of their chicks, there has long been a fascination with the evolution of this bird. Some thought they were the link between reptiles and birds. Others thought they were a modern day version of the Archaeopteryx, a bird attributed as an evolutionary step from dinosaur to bird. There were also similarities in appearance between the Hoatzin and the Archaeopteryx. Recent genetic sequencing of Hoatzin genome now suggests that it is the only surviving member of a lineage that branched off some 64 million years ago (not long after many dinosaurs became extinct) and that it evolved its traits indepedent of the archaopteryx lineage.

I found this one of the most fascinating Mystery Creatured to date, I hope you enjoyed it too. As always, if you have any suggestions for the Mystery Creature spot, please get in contact!

Mystery Creature revealed – the Orchid Mantis

January 20, 2015January 27, 2016nao

Did you guess last week’s Mystery Creature? It is such a master of camouflage that it was difficult to even see it in the picture but it was the very awesome Orchid Mantis (Hymenopus coronatus).

Here are ten facts about this amazing creature:

1. Orchid Mantises are native to the rainforests of south east Asia… the word mantis comes from Greek word “mantikos” meaning “soothsayer” or “prophet”.

2. The Orchid Mantis gets its name from its amazing ability to mimic an orchid flower, with the abdomen and four walking legs appearing as the body and petals of the flower. The insect may be white, pink or purple with a range of colour combinations.

3. What is truly remarkable about the Orchid Mantis is that it appears to exhibit “aggressive mimickry”. According to a 2013 study carried out on Malasyian Orchid Mantis it is not mearly hiding among orchids and using them to lure in its prey but they are the lure themselves. The Orchid Mantis appears to other insects as an actual native flower, so much so that the insect is attracted to it, and once it comes within reach it becomes dinner!

So effective is the Orchid Mantis at this that these initial studies reported it to lure 30% more insects to it than the actual plant itself.

4. Orchid Mantises, along with other Mantids, share a common ancestor with termites and cockroaches.

5. The Orchid Mantis can fly; males are thought to be better flyers than females

6. Orchid mantids are sexually dismorhpic, the females can grow to double the size of the male (about 6cm). The male matures more quickly, taking five to six months to reach full maturity, compared with the females eight months.

7. Female lays a cluster of 50 to 100 eggs, wrapped in a foamy, protein rich layer (Oothecae);

8. The nymphs when hatched, look more like ants (with black and orange/red bodies) but lose these colours as they grow and molt. It is thought that the newly hatched nymphs have this colouration to mimic aggressive or foul tasting insects.

9. Orchid Mantises eat a large variety of flies and pollinating insects such as bees, butterflies and moths. They may also eat small lizards and bananas. They are preyed upon by lizards, toads, certain jumping spiders and bats.

10. As with many other species of Mantises, the Orchid Mantis has spiked forlegs that they use to hold their prey securely in place while they eat.

A Simple Slice of Science – Why do we have five fingers?

October 16, 2014October 16, 2014nao

This week’s questions comes from the youngest junior scientist in the Science Wows household and he wants to know…

Why do we have five fingers?

As it is National Maths Week Dr. Simple is happy to be talking numbers.

References:

1. Why do most species have five digits on their hands and feet?

2. What if our hands had six fingers?

3. Why do we have ten fingers?

"Thought of the day"….Why do hens lay unfertilized eggs?

April 5, 2013August 28, 2016nao

Following on from this weeks blog about all things eggy – today’s thought is …”Why DO hens lay unfertilized eggs?”

It seems like quite a wasteful process, don’t you think? All that protein, fat, nutrients, calcium that go into the making of one hen’s egg – what is the point in going to all that trouble if there will be no offspring at the end of it?

Here are a few of my thoughts on the matter…

Firstly, we are looking at the fairly recent domestication of the species; in the wild it is likely that roosters would be naturally part of the flock and all eggs produced would be fertilized. In the domestic situation roosters are often not present but the evolution of the hen has not (as yet anyway) been modified!

If we look at egg production in any species we will notice that eggs are usually released and developed in a cyclic manner (we humans are no different). If you see this cyclic process as being wasteful at times then the label will fit for most animals, not just the humble hen!

photo credit: martinteschner via photopin cc

Finally, you could suggest that it is a downside to the evolution of the egg shell! Animals that produce soft shelled eggs usually have a requirement for water in the reproductive process. In fact, for many of these species the eggs are fertilized outside the female body. Although the addition of an egg shell removed the dependence on water for reproduction, it also removed the possibility of fertilisation once the egg is laid!

So there you have it, these are some of my thoughts on the subject. I am not suggesting that any of these points are backed up with scientific findings…. the are just the random thoughts of this simple scientist! Maybe you have your own theories to add?

…just a thought!

"Mammy I hatched an egg!"

April 3, 2013July 5, 2014nao

As a mother of three young children I have had many charming moments that I feel I will remember forever…. first steps, first words, how they pronounced a certain word, the list is endless. Memories to cherish for a lifetime…. and then I forget!! Startling but true! More moments forgotten than remembered. However, certain things will stay with me forever…. like when my daughter was five and we got chickens for the first time; she was beginning to learn the joy of finding and collecting the eggs each day. One day she came to the back door with her bounty only to trip at the step and drop an egg. The poor thing burst into tears with the dramatic exclamation…

……………………………….”MAMMY, I HATCHED AN EGG!

Image credit: Graham Ettridge

I will never forget that one! It was hard to keep a straight face as I tried to console my sobbing child. With all the egg activities and treats of the Easter it has certainly got us talking and thinking about eggs in this house, have you ever wondered about these marvels of nature?

WHAT IS AN EGG MADE OF?

Firstly, what exactly is an egg made of and what purpose does each component have?

Image source: http://www.exploratorium.edu

The shell: the egg shell is made of calcium carbonate (95%), just like the enamel of our teeth (see previous post). The other 5% of the egg shell is made up of calcium phosphate, magnesium carbonate and proteins. Although the shell gives the egg it’s strength you might be surprised to learn that it actually contains up to 7,000 tiny holes (pores); these pores allow air and moisture pass through the shell.

The bloom/cuticle: this is a protein coating outside the egg shell that acts as a natural barrier to bacteria and dust while reducing moisture loss.

The membrane: there are two layers of membrane just inside the shell called the outer and inner membrane. These membranes are like layers of skin and contain a protein called keratin, which is found in our own nails and hair!

The yoke: the yellow of the egg contained within a membrane called the vitelline membrane. The yolk is the part of the egg that feeds the developing embryo – it has a very high protein content and is also rich in vitamins and minerals. The yolk contains all of the egg’s fat and cholesterol. The yolk is the primary food store for the developing chick.

The Albumen: this is the white of the egg; it has a high protein and water content. The albumen cushions the developing chick and keeps it moist while still in the egg.

The air cell: this is a pocket of air at the wide end of the egg, created between the outer and inner membrane. The air cell gets bigger as the egg ages.

The chalazea: these are spiral ropes of egg white that keep the yolk in place.

WHAT ANIMALS LAY EGGS?

Animals that lay eggs are called oviparous and they include birds, fish, amphibians, many reptiles, many arachnids and insects, some molluscs and two mammals – the echidna and the platypus. Mammals that lay eggs are referred to as momtremes.

A BIT OF EGG EVOLUTION

The reptile is credited as inventing the egg shell, allowing their young to develop outside the mother’s body. All true dinosaurs are reptiles and they all laid eggs. The development of the egg shell has been a fundamental step in evolution as it allowed the embryo develop in self contained egg, without the requirement for water. This removed animals’ dependence on water for breeding.

HOW IS AN EGG MADE?

In the hen it takes about 24 to 26 hours to produce an egg. An egg is made from the inside out, starting with the yolk which is released from the hens ovary and moves through various parts of the body where another element of the egg is added until finally the finished egg reaches the vent and the egg is laid. Within 30 minutes of laying an egg, the process will start for the hen all over again.

SO WHAT GOES ON INSIDE THE EGG?

The embryo has started to develop in the egg while it is still being made within the body of the hen. Once the egg is laid the development of the embryo will only continue if conditions are correct. If the temperature and humidity levels are right (temp approx 22oC, relative humidity 50% ) the development of the embryo will continue after the egg is laid. This process continues for approximately 21 days. If the egg is being hatched under a broody hen then the hen must turn the eggs regularly.

THE HATCHING PROCESS

Image credit: http://www.waldeneffect.org

Finally, when the time is right, its time to crack out and see the world. The young of many egg-laying species are equipped with an egg tooth – a tooth like projection on the end of a beak (birds) or protruding from a jaw (reptiles) that helps the young animal tear through the membrane and break through the hard shell. The egg tooth will eventually be reabsorbed or fall off.

Chicks and many other animals will hatch from the larger, rounded side of the egg. That is because this is the end where the air cell is usually located. Once the chick becomes too larger to receive enough oxygen from inside the egg it will use it’s egg tooth to pierce through the inner membrane into the air cell space. This provides them with an extra supply of oxygen, just enough to sustain them as they continue the hatching process and crack and break though the egg shell.

We have been lucky enough to hatch a few broods of chicks over the years and it is always so exciting to meet the little ones for the first time.

This is chips – one of our brood!

So the only other question to be addressed is “which came first – the chicken or the egg?” but I think that’s a blog in itself, perhaps for another day!

AN EXPERIMENT TO TRY – HOW STRONG IS AN EGGSHELL?

You would be amazed how strong an egg shell is, although you might want to try this one over a sink!
Hold a raw egg between your thumb and first finger, holding at the two ends and then apply pressure – as hard as you can! You might be surprised to notice that the egg doesn’t break!

If you repeat this but apply the pressure to the sides of the egg, things might not go so well and you might find yourself covered in egg!

So why is this? Although an egg shell can be very fragile, it’s shape can provide it with great strength. This is because the egg is dome shaped at the top and the bottom, just like a bridge structure; this structure means that when you apply pressure the force is distributed evenly over the shell, not just on one point, hence the egg does not crack!

Further reading:
Anatomy of an egg
Eggshell
Poultry reproduction and incubation