Bed bugs and development of resistance

Bed bugs have developed a resistance to the most widely used insecticide http://gu.com/p/4g7e2?CMP=Share_AndroidApp_Blogger

Having it all; sexual and asexual reproduction in Fungi

The world of Fungi continues to amaze me. Today I saw the fruiting bodies of Geoglossum difforme. Fruiting bodies are the small part of the fungus that is above ground, but that is just the tip of the iceberg. Fungi cells are asepate (their divisions break down) so that they grown as long cylindrical tubes called hyphae.  These digest their substrate as they grown though it, in this case, a rotting log.  The mass of hyphae form a ball called a mycelium.  Fungal life cycles are complex and can contain asexual and sexual reproduction, whatever maximises the chances of survival.  Fungal spores (mostly asexual) are single cells that are released from the fruiting body for dispersal. Apparently, fungal taxonomy is based upon the type of spore releasing structure. I don't think we'll go there!

Plant sensitivity

Are plants sensitive? Well they might not have a nervous system but they do respond to stimuli, specifically light, gravity and water.  We call these responses Tropisms.
Here we have a geranium that has been left on a windowsill.  The plant has responded to the direction of light; it is said the be positively photo tropic.
The light alters the distribution of auxin, a chemical that promotes growth, so that one side of a growing shoot grows faster than the other.  In this way the shoot bends towards the light.

I 'liver' you...

'Dissection club students had liver today. We noted the size of the organ (it is the biggest) and the density of the tissue ( it is very metabolically active - when I was an A level student I had to write an essay on the twelve functions of the liver!).
Here we can see the left and right (larger) lobes.  It is still attached to a bit of the diaphragm. The top surface is very smooth and lubricated to reduce friction when the diaphragm contracts.

On the rear side we were able to see the hepatic portal vein which brings glucose rich blood from the small intestine to be converted into the storage carbohydrate glycogen. 

We could also see the gall bladder and bile duct.  Bile is poured onto the chyme (partially digested food) that is leaving the stomach. It is alkaline to neutralise the stomach acid. It's job is to emulsify fat. 

The liver, being so metabolically active, also produces a lot of heat as a by product.  As the blood passes through the liver it picks up the heat which is then distributed to the rest of the body.  The Tudors knew this and therefore thought the liver was a very important organ, like we do the heart.  So they might have said to each other, "I liver you."

Bald as a Coot

It's minus 3 and this Coot is walking over part of the Lake that has frozen.  I was able to observe his unusual feet; they are not webbed like a duck but do have large flaps, so a large surface area to pull efficiently through the water.

Fulica spp

By the way, Coots are described as bald, but not because they are hairless. Bald in this sense means patchy white, like 'piebald' animals

Simple behavioural responses in Woodlice

Today we have been setting up Choice Chambers for Woodlice.  A choice chamber is what it says it is; we provide the Woodlice a choice of environment, then observe where is 'chooses' to go.  Of course, the wood louse is of such little brain that there is not really any thinking about it, and therefore not really any choosing. It is a simple response to a stimulus.  ( a stimulus is a detectable change in the environment).

We decided to find out if our Woodlice prefer dark or light conditions. We set up a choice chamber, essentially a large Petri dish, with one half covered in a black bag and a bright light on the other half.  We introduced ten Woodlice and gave them five minutes.  Then we recorded how many were in each half, and were able to do a chi-squared statistical test on the results.

Most liked the dark conditions. This is a simple behavioural response in which the wood louse exhibits a kinesis. In response to the stimulus, light, it increases its rate of movement.  We observed them scurrying around madly in the light.  This is not so mad as it may seem.  By moving around they are more likely to find their preferred conditions (dark) more quickly. And when they get there, they slow down and stay there.  

If you are a wood louse, it may be a matter of life or death.  If you are under a log or stone, it may be dar, but you can't be seen by predators ( birds) If some unthinking human goes and exposes you, you better run like the clappers.

Cold snap kills off soil pathogens

I, for one, am glad that the weather is turning colder.    Crops and insects at the bottom of the food chain can find that warm weather increases the parasitic load.   This can have consequences for species higher up the food chain, especially birds, who may suffer if there are not enough insects to eat. 

 A good frost can reduce these viruses and bacteria that cause harm..

An interesting article about 'winners or losers' in the cold weather was published recently.

http://www.theguardian.com/uk-news/2016/jan/09/warm-winter-cold-britain-birds-weather-wildlife

Dissection Club - Inflating Lungs

Today we had lungs to dissect.  The students are always amazed at how they inflate to three times the size.  It is quite something to watch, and a bit daredevil to try yourself by inserting a rubber tube into the bronchi. ( Tips: 1. it can be a two person job to hold the lungs and the rubber tubing, you really want to keep the end you put in your mouth well away from the specimen! 2. Hold the lungs up high the try to ensure there are no blockages in the bronchi or bronchioles by being folded. 3.  Make sure you only blow out and immediately move you head away so that you don't get 'exhaled', or splattered, all over. 

We took some time to look at the features of a gaseous exchange surface as exemplified by the lungs: large surface area everyone expects.  Moist? Most students forget that gases dissolve in water and thus diffuse across exchange surfaces quicker.

To me, the most interesting thing is the role of the diaphragm.  Here we are holding it up to show how tough the tissue is (like the skin of a drum) and how it attaches to the inner wall to form a complete seal of the thoracic cavity. How contraction of the muscle, seen here, pulls it flatter, thus increasing the volume in the chamber, decreasing the pressure, and causing inhalation as air is drawn in down a pressure gradient.

S

Cheeky Grey Squirrel!

So cheeky and was enjoying his acorn so much, he let me get quite close (sorry, this is not Wildlife Photography;I'm only snapping on my phone)!
The story of the Grey Squirrel, introduced from America, and out competing the native Red Squirrel, is well known. But why are they such good competitors? Yes, they are bigger and heavier tan red squirrels, and if competition were literally a fight, they would probably win.  In ecological terms, however, they are better adapted to survive in a certain environment than red squirrels. Red squirrels favour pine trees and their seeds for habitat and food almost exclusively. Whereas grey Squirrels have a more eclectic diet, can survive in mixed woodland with deciduous broad leaved trees, coming to the ground often to feed on a wider variety of nuts and seeds.  We all know what has happened. Grey squirrels have pushed red squirrels to the margins, to the north where there are more pine forests.  And the islands, like Isle of Man, or Brownsea Island, because one thing grey squirrels can't do is swim.

The Yellow Brain Fungus

Tremella mesenterica or the Yellow Brain Fungus.  a jelly fungus seen in all its glory due to the wet weather; otherwise it is small and crusty!

 With thanks to my sister Katharine who spotted this today!

Otzi the Iceman keeps on giving..

Ötzi the Iceman's 5,000-year-old stomach bug sheds light on human migration http://gu.com/p/4fjb6?CMP=Share_AndroidApp_Blogger

Lichens; Pioneer Species

I have to say, I love Lichens. Just beautiful, in their many shapes and colours, as well as awesomely adapted to surviving harsh conditions. I was teaching about them as Pioneer Species today in the Lithosere.  They live on Bare Rock, an inhospitable environment indeed.  The Lichen is a symbiotic relationship between a fungus and an algae.  The algae is photosynthetic and hence autotrophic (it synthesises its own food and the fungus benefits as it cannot). The fungus on the other hand, is heterotrophic and specifically performs extra cellular digestion by secreting enzymes onto its substrate. In this instance, the substrate is the Rock which is slowly dissolved, providing some minerals but essentially giving the fungus a purchase.  And of course, the algae benefits.
Lichens lend themselves to student projects.  Their distribution can be easily investigated using a mini-quadrat and calculating percentage cover.  Comparisons could be made between rocks facing north and south, different rocks or different areas, or classically, the effects of pollution as Lichens are well known to be intolerant of sulphur dioxide.Statistical tests such as standard error and 95% confidence limits would be an appropriate way to analyse such data.

Tufted ducks Aythya fuligula

I was delighted to see five male Tufted Ducks on my lunchtime walk around Lakeside Country Park.  I haven't seen them here before, so wonder if they are residents or have flown in from somewhere cold? Maybe Iceland?

Octopus Dissection

Really enjoyed dissecting the Octopus. One of the most valuable lessons in dissecting is feeling the texture of the material.  I found the Octopus Beak, and it is a surprisingly hard material, like keratin nails or claws, which the Octopus uses to prise open mollusc shells and scoop the contents out to eat.

fungus identification

Can anybody identify this Fungus which was seen in the Outwoods, Charnwood Forest?

Greetings!

Hoping to engage with fellow biologists, students and lovers of nature on my blog.  A Biology Lecturer/ Teacher, I 'see' Biology all around me and  I  wish to link the theory of what I teach with real world examples.   I like to take photos of the world around me and I constantly strive to understand more about living things myself, so please do comment; adding, correcting, questioning! I'm intending to collate together things that interest me about Biology in the newspapers or on the TV as well.