Egg-like fungus

This is amazing!  It is the volva or immature fruiting body of a fungus.  The recognisable stem and cap are encased in this gelatinous material, and they are usually found just below the ground.  This was found in an area where I have found stinkhorns previously, so I think it must be the same species, Phallus impudicus

Dissection Club - Lovely Lilies

Today we looked at the Reproductive organs of flowers, which are large and easy to see in the Lily.  The colours and scent of flowers attracts insects which are useful in the dispersion of pollen for reproduction.

Flowers reproduce sexually and have both male and female organs, although to prevent self-fertilisation they mature at different times.  In the photo we can see the central female organs (the stigma, style and ovary), surrounded by a number of male anthers (brown).  The specimen on the left is from an open flower, and the one on the right is from a bud.

The male sex cells are the pollen and these are small cells that are dispersed by the wind or by insects that come to feed on the sugary nectar that exudes from the female stigma.

The stigma is sticky so that foreign pollen which lands on it will bond.  A pollen tube grows down the long style to the ovary which is at the base.  Fertilisation takes place when the male sex cell (pollen) fuses with the female sex cell (ovule) becoming a seed.

The flowers' petals drop away as their job is done, but the ovary swells and becomes a fruit to protect the seed as it too falls to the ground.  In some species, the swelling is large, colourful and packed with sugar which is attractive as a food source for animals, including birds. When they eat the fruit, the seed will pass unharmed (protected by a seed case) through the digestive system, eventually being egested. In this way the seeds will have been dispersed far from the parent plant and will be able to colonise new areas, thus ensuring the success of the species

Leaf pigments

The colours of my Soomack are stunning.  

Leaves are usually green in the growing season, of course, and brown when they are dead! But as the temperatures drop in autumn and the rate of photosynthesis declines,  the leaves transition through a very beautiful sequence of green, orange, yellow and red before they fall off the trees.
Two pigments, chlorophyll a and chlorophyll b, are responsible for the green colour.  They absorb red and blue wavelengths of light, but reflect green, so that is the colour we observe. The light energy absorbed is what is converted into the chemical energy of glucose, made in the process of photosynthesis.    It is also required to make chlorophyll, so when the light starts to fade at the end of summer, so too does the chlorophyll molecule.
Other pigments may be present in the leaf to maximise the amount of light energy that can be absorbed.  A second group of pigments are carotenoids, which absorb blue-green pigments and reflect the red end, hence they look orange in colour. These pigments are a little more stable than chlorophyll and last a bit longer into the autumn.  So as the green colour fades, the oranges and yellows come through.
Some leaves have a third pigment, the red anthocyanin.  These are compounds that are in the cell sap and are synthesised from sugar.  The higher concentration of glucose, the more purple the anthocyanin.
As chemical reactions are involved, many variables influence the reaction; different species, sugar concentration, pH of cell sap, and external factors such as light wavelength, light intensity, temperature, and so on.  Which is why there is such a wonderful spectrum of colour at this time of year.  Enjoy.

Forever fungi

 Lycoperdon excipuliforme

Fungi are not autotrophs like plants. They do not make their own food.  No, fungi are heterotrophs, which means their food has to be digested and absorbed (like in animals, although, clearly, only in this respect!).  Fungi perform Extracellular digestion.  Their enzymes are secreted outside of their body. The enzymes digest the large and insoluble organic molecules (eg wood) into small and soluble ones like glucose.  This can be absorbed into the body and assimilated into more complex materials for growth such as proteins.  Hence fungi are found growing through their food source, eg a tree stump.

Phallus impudicus, the common Stinkhorn

Phallus impudicus was named by the father of taxonomy, Carl Linnaeus, himself.  The common Stinkhorn can be both seen and smelt in the woodland at this time of year.  It is said that Darwin's granddaughter, Etty Darwin, was so upset by them that she attacked them with a cudgel at dawn.

A ten minute walk in the woods on my way home from work yielded a great array of fungi.  I highly recommend getting out and about to observe the vast number of species of every shape, form and colour that pop up in the autumn.

Conkers bonkers

When I was a kid,  nothing could be more thrilling than finding conkers under a horse-chestnut tree in autumn.  The nut, up to 4 cm in diameter, is shiny and smooth, with a scar on one side.   The spiky fruit opens as if it has been scored with a knife, so straight is the cut,  and the conker tumbles out of the fruit, usually one but sometimes two or three.

The horse-chestnut tree is a huge beast.  Massive boughs, five to seven sprigged gigantic leaves, large white  towers of flowers with small pink dots on the petals, and of course, a big scent.  Wrongly called a chestnut, though might be poisonous to horses. The conker does contain toxic saponins.  However, whether there is any truth to the belief that they keep away spiders is not known.

Aesculus hippocastanum

Dissection Club; the Locust

We dissect all sorts at this club, and today it was the turn of the Locust, a fairly large representative of the class Insecta.

Insects are Arthropods with jointed legs, segmented bodies and an exoskeleton made of chitin.

They have three body regions; the head, thorax and abdomen.

The main reason for dissecting insects for A level Biologists is to observe the Gas Exchange system.  Locusts cannot get enough oxygen to their cells by diffusion alone.  (Only fairly small organisms with a relatively large surface area to volume ratio can get enough oxygen through their surface) . 

Insects have a simple tubular system  in which oxygen can enter the body through holes called Spiracles, and can move down a concentration gradient through tubules called tracheoles to the respiring tissues.

Compression of the body brought about by the movements of the legs can aid gas exchange.

Geo-caching challenge

At this time of year, the grey squirrel is incredibly busy, running up and down trees, running madly around woodland, risking life and limb crossing busy roads, all in a frenzy to collect as many nuts as possible as they rain from the skies.  Autumn is indeed bounteous on the nut front, and squirrels behave as if they are on Supermarket Sweep.
What to do with so much food?  Evidence of them eating as many as possible is everywhere, with half eaten nuts strewing the paths.

But they can also be seeing hiding them in caches.  Squirrels do not hibernate but they may sleep for long periods in the winter.  When they wake up, they will be hungry, and their well-developed spatial memory, as well as their excellent sense of smell, will lead them straight to breakfast.