Archive for March, 2012

So, we’re getting to that time of year where Easter and Summer holidays are starting to creep into our thoughts…But spare a thought (and a prayer) for all those students who will be spending their Easter break preparing for upcoming exams! So here’s a few ideas to help kick start your revision, and hopefully help lead to the grades you are capable of! 🙂

  1. Know what exams you are doing and when – if you are sitting GCSEs or A-levels, your exam timetables will be available to you via your exam board; If you are doing KS3 exams, your teachers will tell you when your exams are – make sure you ask! Once you know when you are doing your exams you should….
  2. Make a revision timetable – A3 size is best, put it somewhere you will see it, and be realistic!! If you know you’re not going to miss **insert whatever TV programme you cannot live without**, then don’t plan to do revision in that time!
  3. Timings – Decide how much time you need to revise each subject and add this to your revision timetable – if you know you’re good at science, then don’t spend as much time on it as you would a subject you struggle with. Once you know when you are supposed to be revising, and what you need to do, then get to it! 🙂 Remember the following also…….
  4. Take a break – for every half hour you study, you should take a 5 minute break. Your brain will need a rest! Try to resist the urge of turning on your laptop or TV for those 5 minutes – it will leave it harder for you to return to your revision. Take a short walk, get some fresh air instead.
  5. Brain food – Increase your mental agility and help improve your memory by choosing the right foods such as oily fish, wholegrain etc. (or if you are like Miss Gilleece who hates fish, you can buy supplements instead of the fish…)

There are so many books, teachers and websites that can help you with your revision, but you do need to know where to look.

Normally your teachers should be your first port of call – remember they know what they’ve been teaching you, and what exam boards are looking for in your answers, so always ask if you’re unsure!

If you opt for buying a revision guide, please make sure you check it is suitable for your level of exam and exam board! Any good book shop should sell a range of revision guides, don’t be afraid to open it up and see if it looks like a good one! (Just don’t try reading it from start to finish without paying for it!!)

Some websites you might find useful: for KS3 and GCSE for GCSE and A- level for GCSE for KS3 and GCSE a search engine dedicated to finding revision resources

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!