Archive for the ‘Biology’ Category

Welcome back!

Posted: September 27, 2012 by Mr Pimentao in Biology, Chemistry, Physics, Uncategorized
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Loreto Science is back , and welcomes everybody to a new year of discovery.
A year of exciting activities is just beginning, so we’d like to invite you to join Miss Gilleece on a journey through the world of Mad science every Thursday at 12:45 in SC5.

This week saw year 7 and 8 students getting to grips with lighting effects. The group enjoyed using prisms and filters to come up with some spectacular images (and stories!) for their light shows – with some trying to act out an X-Factor audition!

The club will hopefully see students gaining a Crest award by the end of the year; some of the topics we will touch on will include rockets and medical physics, alongside a project the girls will design for their Crest award.

So if you haven’t already come, don’t worry!! You can drop in any Thursday, but I’d love to see you there every week! ūüôā

See you all next Thursday!

Miss Gilleece

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Over 6th July 21 AS/A2 Biology students (and Dr Paul and I) set off to Snowdonia to study ecology as part of the A2 Biology course. 

North Wales

Staying at a Field Studies Council centre in Betws-y-coed, the first evening began with setting Longworth mammal traps (non-lethal) so that we could get an estimate of the population of small mammals in the centre grounds. After dinner we had a bonfire and a game of football on a pretty muddy pitch (it had rained most of the day whilst we travelled) but it was good fun.

The following day we checked our mammal traps before breakfast. Another school had also set mammal traps but they hadn’t gone to such great lengths to conceal them and subsequently the squirrels had raided the traps and eaten all the bait.¬†

Wood Mouse

Our traps however were untouched, and yielded 4 wood mice and 3 bank voles.

Bank vole

After letting them go we travelled by coach to Morfa Harlech, a nature reserve with a textbook-quality sand dune system. Walking across the dunes from the sea towards the land allowed us to record the changes in plant and animals species and the local environment, highlighting the process of succession. At the end of the dune system is woodland that was once bare sand but over time has been colonised by successive plant communities.

Sand dunes at Morfa Harlech

That evening the students worked in the classroom to process their results, and then we played another game of football.

Sunday saw us travelling to Penmon Point on Anglesey to study a rocky shore.

Penmon Point, with Puffin Island in the distance

Penmon Point

 Starting at the low water mark we moved higher above sea level, recording the changes in types of seaweed and plants, limpets, barnacles and crabs.

Velvet Swimming Crab

¬†Rocky shores exhibit something called ‘zonation’ – the distribution of the different organisms is heavily influenced by different local environmental conditions.

On the return from Penmon Point we stopped off briefly at Cwm Idwal, a spectacular corrie (bowl-shaped glacial valley) formed by over 2 million years of glaciation.

Cwm Idwal

The glacier is long since gone, although it has left a crystal-clear lake in its place. Cwm Idwal is special for many reasons, but particularly since it is home to the incredibly rare Welsh Tufted Saxifrage, an alpine plant that is a leftover from the time when Britain was much colder just after the last ice age.

Tufted Saxifrage – a survivor from the last Ice Age.

 The plant clings on to life on the cold backwall of the valley where few other plants can survive.

That evening didn’t see any football – instead the students dressed up as pirates and took part in a treasure hunt and then a piratey sing-song around a roaring fire!

Monday was our last day, but the morning was spent collecting invertebrates from a fast-flowing freshwater stream and then looking for a correlation between the different species and the velocity of the water.

A cased caddisfly larvae from a freshwater stream.

After that, we travelled by train back to London – rather tired but having had a really good trip. The students were amazing – they worked so hard, got really enthusiastic about everything and were a credit to themselves. Well done!

Welcome to part 2 of the Arthropods special, and today I’m giving you a whistle-stop tour of the myriapods. This group includes centipedes and millipedes (as well as a couple of less important relatives), with approximately 12,000 species currently known.

Centipedes and millipedes are common enough if you look through leaf litter or under stones and flowerpots in the garden. What’s the difference between centipedes and millipedes? Well, a common mistake is about the number of legs (i.e. 100 for a centipede and 1000 for a millipede – this isn’t true). The number of legs in a centipede varies between 20 to 300, and in millipedes ranges from 36 to 750.

The easy way to distinguish between a centipede and a millipede is to look for the number of legs per body segment. A centipede has 2 legs per body segment and a millipede has 4 legs per body segment. They also differ in terms of diet – centipedes are active hunters and carnivores whilst millipedes are detritivores (eating decaying leaves).

Centipedes and millipedes are a very successful group, and have been around on the Earth for at least 440 million years. An earlier relative of centipedes and millipedes called Arthropleura lived 300 million years ago and was able to reach lengths of 2.5m. This makes it the largest land invertebrate ever, and could grow this large due to higher concentrations of atmospheric oxygen at the time.

So, here are some interesting photos of centipedes and millipedes from around the world. Enjoy!

Arthropods are great. I love ’em!

What are arthropods, you might be thinking? Well, the term arthropod (from the Greek for ‘jointed foot’) describes organisms that have hard exoskeletons, segmented body¬†and jointed limbs – animals such as insects and spiders.

Arthropods are a remarkably successful group,  tracing their history back to a common ancestor that lived aabout 500 million years ago. Thanks to their hard waterproof exoskeletons they did very well in the sea, and were in fact the first animals on land. They later diversified into at 5 main groups:

  • Myriapods – including centipedes and millipedes
  • Chelicerata – including spiders, scorpions, horseshoe crabs and mites
  • Trilobites – an extinct group of marine animals (looked a bit like woodlice, but weren’t related)
  • Crustaceans – including crabs, lobsters, shrimp, barnacles and woodlice
  • Insects– including ants, bees, beetles and butterflies

    The arthropod family tree

There are at least over 1 million known species, and they make up 80% of all living species (that means if you took 100 random species from anywhere on the Earth, approximately 80 of them would be arthropods). They are incredibly populous – a conservative estimate of the number of insects alone (currently alive) is 10,000,000,000,000,000,000 (that’s 10 quintillion). That’s quite a lot.

So, in celebration of these fascinating and diverse organisms, this is part 1 of 5, each focusing on a different arthropod group. First up is Chelicerata – enjoy!

 

Is there anybody out there?

Posted: February 26, 2012 by Mr Pimentao in Biology, Space
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Forget about little green men, ET or Alien – they don’t exist. Or at least we don’t have any proof that they do. Despite this, the search for extra terrestrial life is now as lively as ever : from the discoveries of planets orbiting other stars in our galaxy to the SETI (Search for Extra Terrestrial Intelligence) project, scientists are scrambling to find a glimpse of life away from our own home planet.

Exoplanets and the Goldilocks principle

Exoplanets are planets that orbit stars other than the Sun. For decades astronomers had suspected that other stars in our galaxy might have planets orbiting them ( just like the Sun has Mercury , Venus, Earth, and so on… ) Like all the other scientific predictions, you can only confirm it if you have enough evidence to back it up. Guess what – for the last ten years or so, astronomers have found evidence that in fact there are planets orbiting stars in our galaxy.

Planet in transit across the star disc: Picture: ESO/L. Calçada

The problem with seeing planets orbiting stars so far away from us is that the brightness of the star outshines the tiny amount of light reflected by the planet. Only very recently , with developments in image processing software and improvements in CCD technology have scientists been able to detect planets. But this doesn’t even mean that we can actually “see” the planets – we can’t , at least not directly. We must look for clues in how the light from these stars reaches us.

One way of telling if a star has planets orbiting it is called the “Planetary transit” method. ¬† Whenever a planet is placed between us and the star, we can detect a small decrease in the brightness of the star. Imagine a mosquito flying in front of a lamp – whenever it flies between us and the lamp, we can see that the lamp seems to get dimmer because the mosquito blocks a tiny bit of its light.¬† The same happens with a planet that orbits around a far away star. Every so often the planet blocks some of the star’s light and the star appears to have dimmed by a¬† little amount. Scientists look out for these tiny changes in the brightness of stars and use their data to compare the size of the planet with the size of the star.

This is all fine, there are more planets in the Universe than those we have learnt about in Miss Gileece’s lesson…. My Very Easy Method Just Speeds Up Naming Planets… But is there life living on them? Do they have BBM?

The answer is….. we can’t tell if there is life on any of the exoplanets that were found, let alone whether or not they have BBM. One thing we know is that life as we know it has first appeared in liquid water –¬† right here on Earth, millions of years ago. So, we can be certain that planets where liquid water exists are more likely to have life.¬† The planets that obey this condition must be at the right distance from their star for the temperature to be just right for liquid water to exist. Depending on the kind of star , and on the size and composition of the planet, the temperature is just right for liquid water if the planet orbits the star at a range of distances often called “the Goldilocks region”.

This raises the question: how do we know if these exoplanets have liquid water? And if they do have liquid water does that definitely mean that they have some kind of life?  Life on Earth evolved in water , but there are so many variables to take into account that it is currently impossible to prove that there is indeed other life forms in the Universe.

So, if you were expecting a YES or NO answer to the question you may now be disappointed (or not!). All we can say is that most probably there is life somewhere in the Universe, possibly in a planet orbiting one of the hundreds of million stars in our own galaxy, the Milky Way.

Happy birthday to you, happy birthday to you, happy birthday dear Charles Darwin, happy birthday to you!

Happy Birthday Darwin!

On this day in 1809 Charles Darwin, arguably one of the most important scientists ever, was born in Shropshire. Charles Darwin is famous for his book On the Origin of the Species where he introduced ideas to explain the origin and diversity of all living species via Natural Selection and Evolution. Darwin was interested in most things, and his work as a geologist and naturalist gave him to opportunity to travel around the world on a 5-year voyage aboard the ship HMS Beagle. Keeping careful notes and making copious observations during the expedition, Darwin saw great biodiversity and it allowed to him to begin considering the origin of this. When he returned to England he began to formulate his idea of Natural Selection.

HMS Beagle

What is Natural Selection?

Darwin had noted that nearly all the species he had encountered were perfectly adapted to a variety of different habitats, diets and lifestyles. His visit to the Galapagos Islands (near Ecuador) had allowed him to study a group of birds (now known as Darwin’s Finches). He was amazed at the variety of different beak shapes and sizes, each adapted to a different way of life.

The Galapagos Islands

How did this happen? Natural selection requires three factors. The first is variation (differences) between individuals. The second is competition between organisms (e.g. not enough food to feed every organism) and finally an environmental change.

Darwin postulated that originally a group of finches arrived at the Galapagos islands from mainland Ecuador. There was variation of beak size within this group of finches. Because there were different food sources on the island (seeds, fruit, insects etc) different beak sizes were more suitable for different diets. For example, large beaks would be able to break open seeds that smaller beaks wouldn’t. If there were plentiful seeds, the larger beaked birds would find more food, have more offspring and therefore pass on the genes for the larger beak. This would continue as long as larger beaks gave a survival advantage. Eventually, with successive generations and continued ‘selection’ for a certain feature, the original population of birds diversified into many different species.

Darwin's Finches

Darwin realised that this same process, occuring over millions of years, could explain the diversity of all living (and extinct) species.

The Theory of Evolution has shaped our understanding of diversity, formation of new species and our position in the Tree of Life. So, thanks Darwin, and Happy Birthday!

The Tree of Life

 

On 7th February 48 students from Year 11, (accompanied by Mr Bilton, Miss Vine, Mr Pimentao and Miss Gilleece) travelled to Essex to visit the npower-operated Tilbury Power Station. The students study the generation of electricity as part of their course, so this was an excellent opportunity to see where it all happens. The Tilbury site was originally a coal-fired power station, but this year it switched to using biomass as the fuel source, as part of a programme to be ‘greener’ and depend on renewable sources.

Tilbury Power Station

The biomass used at Tilbury is wood pellets, produced from the sawdust and waste of the Canadian lumber industry, so it’s a good use of a material that would otherwise just be wasted. It also has less impact in terms of CO2 production than coal, because it’s not burning carbon that’s been locked away for millions of years.

Properly kitted out in hard-hats, ear defenders and high-visibility jackets the students were taken on a tour of the power station, at one point standing inside a 65m furnace which reaches temperatures of 1500¬ļC (luckily for the students it wasn’t on at the time…). The scale of the facility is hard to imagine, but it gives you an appreciation of engineering behind the process.

Safety first - hard-hats and ear defenders!

The process of electrical generation is actually remarkable simple. When the biomass arrives it is crushed and then blasted into the furnace where it burns. The furnace is lined with pipes that contain ultra-pure water. As this water heats up it turns to steam. This high-pressure steam is used to turn turbines (converting heat energy into kinetic energy), and the turbines rotate an electro-magnet within a coil of wire. The movement of a magnet within a coil of wire creates the electrical current (thanks Faraday!) and that’s all there is to it.

Generating electricity - what's happening inside?

The students were also able to study some of the chemistry and biology surrounding the issue of power generation. Using conductivity meters the students recorded how many dissolved ions and minerals were in drinking and filtered water. They then compared it to water that had been through an ion-exchamge resin and were surprised to see that there were no ions left at all. This super-pure water (which actually tasted a little bland) has to be used in the power station to prevent damage to the pipes (picture the inside of your kettle..). The students then had a look at the local water quality by pond-dipping and looking for indicator species; species that tell you how clean the water is by their presence or absence. Having found a variety of insects including Common Backswimmers, Damselfy nymphs and Diving Beetles (and even some fish) everyone was surprised to conclude the water so near a power station was actually good quality and supported a diverse community.

Damselfly nymph - this larval form indicates good water quality

Common Backswimmer - this insect swims upside down

The students had a really good time and certainly learned lots about where their electricity comes from and how best to manage our energy resources so that we can live in a sustainable and ecologically-sensitive way. Many thanks too to the staff at the power station for giving us such an enjoyable day!

Big Schools Birdwatch 2012

Posted: February 1, 2012 by Mr Bilton in Animals, Biology, Field Work
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Last week every member of Year 7 and 8 took part in the RSPB’s ‘Big Schools Bird Watch’ event. Having placed hand-made bird feeders around the school the previous week, students spent a lesson outside, armed only with a pair of binoculars, a pencil and an ID guide, trying to spot some of the common (and more elusive) birds in the school grounds.

Birdwatch 2012 - The school ground support a large variety of different bird species.

It was certainly an eye opener, and the graph shows the variety of different species seen. The students were recording the maximum number of any given type seen at the same name. As you can see, we’re very lucky to have such biodiversity in the school grounds and we’re looking forward to comparing our results when we participate in the event again, next year.

If you’re interested in finding out about birds, have a look at the RSPB site http://www.rspb.org.uk/.

Dr Frederick Banting - pioneer of insulin treatment

This week marks the 90th anniversary of the discovery and isolation of insulin by Dr Frederick Banting, a discovery that has saved and improved the lives of millions of diabetics.

What is Diabetes?

Diabetes is a serious disease that affects over 250 million¬†people globally, in which the body either doesn’t produce enough insulin (Type 1)¬†or doesn’t respond to the insulin that is produced (Type 2). This leads to a high blood sugar level, and this causes a variety of medical problems if not managed. 90% of cases are Type 2 diabetes.

 
What is insulin?

Insulin is a hormone produced by the pancreas. It plays a central role in controlling and regulating the amount of glucose in the blood. It does this by causing cells in the liver (and some other cell types) to store the glucose as glycogen. Insulin is injected by Type 1 diabetics as part of their treatment. Type 2 diabetics may sometimes need to inject insulin, but their treatment and management focuses mainly on lifestyle and diet control.

How was insulin discovered?

Before insulin was discovered, diabetes caused death in nearly all cases. The only treatment available was a strict controlled diet and this only gave the patient a few more years.¬†In the 19th century a German medical student called Paul Langerhans had identified a set of cells in the pancreas that didn’t seem to have a function. (These were later identified as beta-cells which produce insulin). A few years later two other German scientists showed that the pancreas was involved in controlling blood-sugar, because they found that dogs that had their pancreas removed developed diabetes.

Location of the pancreas

In 1920 Dr. Frederick Banting, a Canadian surgeon in Toronto, developed a process for isolating a secretion from the pancreas that was shown to prevent diabetes when injected into dogs that had had their pancreas removed.¬†With this isolated secretion now named¬†‘insulin’, Dr Banting and his team started testing on human subjects, beginning with themselves. They managed to develop the correct dosage and in January 1922 gave insulin to a 14 year old diabetic boy, Leonard Thompson. The insulin worked perfectly, and Leonard recoverd from near-death. In 1923 Banting was awarded a joint Nobel Prize for Physiology or Medicine and a medical company went on to mass produce insulin.

Leonard Thompson - the first person to receive insulin.

Whilst insulin doesn’t cure diabetes, it means diabetics are able to regulate their blood glucose levels and stay alive. Perhaps you’ll agree that the discovery of this treatment is one of the great medical advances of the 20th century.

Nature at Loreto

Posted: January 16, 2012 by tvineloreto in Animals, Biology
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As you stroll from building to building or sit out on the front lawn on a warm sunny day have you ever taken the time to stop and look around at the school grounds. We are blessed with beautiful grounds which are a haven for wildlife. The well established trees, lawns, flowerbeds and new pond provide a wide range of habitats and hidden within is an amazing array of animals, you just need to know where to look.

You cannot have failed to notice the bin-diving squirrels or heard the noisy cackling of the magpies but what else is there to see if you just take the time to look and listen? ¬†We have a large variety of birds visiting or living in our grounds and during the week of 23rd Jan ‚Äď 28th¬†Jan, students at Loreto¬†will be taking part in the Big Schools Birdwatch organised by the RSPB, an annual event used to collect wildlife¬†data on a national scale.

If you would like to find out more about the RSPB’s¬†Garden Birdwatch 2012¬†or take part in your own survey clink on the link¬†¬†¬†¬†¬†¬†¬†www.rspb.org.uk

Here are just a few of the birds you might see around Loreto College

The Robin

Robin (Erithacus rubecula)

The Robin ( Erithacus rubecula)

Probably the best known British bird, both the male and female have the distinctive red face and breast, white underside and brown plumage. Juveniles are brown. Robins are highly territorial and signal their presence with a beautiful, melodic song.

 They are a gardeners companion, following a gardener to snatch up any worms or insects disturbed whilst they work.  Often spotted in the flowerbeds by the main school entrance

 
 
 

Blackbird

Blackbird (Turdus merula)

A very common sight in parks and gardens. Males are glossy black with a yellow beak and yellow eye-rings,females are brown. They have a rich and beautiful song and sing from high points such as rooftops  and aerials.    A common sight on the school front lawn and by the Mary Ward Block.

 
 
 

Dunnock

Dunnock (Prunella modularis)

 Small, with brown plumage but has a greyish hue on the sides of the head and on the breast.

Often mistaken for a sparrow as it is similar in size and colour but Dunnocks have a much slender beak. Seen  in the flowerbeds by the main entrance and in the fenced off area by the pond.

 

Blue Tit

Blue Tit (Cyanistes caeruleus)

 Small, colourful garden bird and a regular visitor to bird tables. It has a distinctive ultramarine cap, wings and tail and a yellow breast. Face is mainly white with a horizontal black line through the eye. Breast is yellow with a small black vertical stripe

 Another gardeners favourite due to its love of small insects and caterpillars. Its acrobatic antics on bird feeders and fat balls make it an entertaining bird to sit and watch.

 Seen throughout the school grounds especially the magnolia trees in front of the school office.

Great

 
Great Tit (Parus major)

 Not to be confused with a blue tit, it is slightly larger and has a black cap which extends down the side of its head as far as the eye socket. It has white cheeks and a yellow breast with a large black central stripe.

 Seen throughout the school grounds.

Mallard

Mallard (Anas platyrhynchos)

 Male has an emerald-green head and blue and white band on wing. Female is predominantly brown but with the same blue and white plumage on the wing.

A spring time visitor to Loreto often seen strolling across the front lawn or taking a nap in the middle of it.

Song Thrush

Song Thrush (Turdus philomelos)

Named after its wonderful song. A medium-sized garden bird with brown plumage and a very characteristic pale breast with v-shaped dark spots on.¬† Another gardeners friend due to its love of snails. It is common for a thrush to have a preferred ‚Äúanvil‚ÄĚ , a large stone used to smash open the snail shells.

 Seen on the main lawn and in the shrubs along the main school wall.

There are many more species of birds living in our grounds, why not see what you can spot?