Steam Diversity Survey: Invertebrate ID's

Following on from doing the stream diversity in Brecon. We pickled the specimens we caught and then a week or two later we started trying to identify them.

I started with a stonefly (Plecoptera) larvae and a mayfly (Ephemeroptera) nymph.
Its easy to distinguish what is a mayfly or stonefly without using any keys however I did so the first time, just to check and its all good practice I guess. A stonefly will always have two tails whereas a mayfly will usually have three (although some have two). then the gills are the second easy detector to see which it is.

(Right: Stonefly specimen under the microscope)

Stonefly

I used a simple key to find out which family it was. which was the PERLIDAE family. The steps I took are as follows:

1. 3 tarsals not roughly equal lengths. 
2. The 3rd tarsal is obviously longer than the first two combined
3. it has obvious gills at the base of each leg ('hairy armpits')

I then got a stonefly book that goes further tan the family and tried to find the species. It was quite easy as there was only two species in this family and so I narrowed it down to:  Perla bipuncta. (left: My field notebook; rough diagrams of stonefly.)

Mayfly

The mayfly (photos below; under the microscope) was harder to identify than the stonefly. I narrowed it down to the family: HEPTAGENUDAE. It has a pronotum with flange-like extension and its eyes are dorsal. 

Im pretty sure that the species is Ecdyonurus insignis (eaton), however the book for the mayfly ID's wasnt as easy to understand and was harder to distinguish between species. However if you look closely at the underside of the body there are dark marking on the underside of the body (you can see this faintly in the picture to the right).

If you want to see more of these photos go to my flickr: Stream Diversity and Invertebrate ID's

(above: my field note book with 

notes and diagrams of the specimen)

Dissecting Squid

Its always nice to start of your almost non-stop ten hour day with a squid dissection at 9am on a Monday morning.

 The same as previous dissections, I drew the external anatomy before i started the dissection. I drew it laterally as it gave a better view of the head and tentacles.There was only enough time for one diagram I thought this was the best.

(above: diagram of the external anatomy of the squid. I took it before id finished my sentence at the bottom, whoops!)

Then we dissected the squid (this dissection was done in pairs). First we had to work out if we had a male or female. There are not ovary's which is the obvious sign. Ours had a penis and a spermatophore sac which has a different texture to what's around it for example the digestive caecum. 

(above: the dissection of the squid.)

After we had decided which gender it was, we then got to locating where certain things were: ink sac, heart, vena cava, rectum etc. We filled it with water so that we could see things better and found the heart (with a little help as its small and hard to spot). With all things located I then drew the internal anatomy of the squid.

(above: Internal anatomy of the squid. I did correct the spelling on this after I took it.)

We then had to do the rest of the write up, explaining functions of some of its anatomy (eg. fins/ink sac). 

This was one of the smellier ones,  even though I was wearing gloves, I still had to wash my hands a good few times to get the squid smell out.

Dissecting Lug Worms

This ones a bit late, a fortnight ago my dissection for Diversity of Life 2 was lug worms. lug worms feed on Plankton and Detritus from water that is washed into their burrows. They live in the sand in coastal areas.

I drew its external anatomy before the dissection. I got marked on the actual presentation of my dissection of which I did well. 

Once I finished the dissection I drew the internal anatomy. After the dissection I looked at the differences between earthworms and lug worm (this was mainly based on the external anatomy). I then had a live earthworm and had to describe the way in which the worm moves. 

the latter part of this was harder than imagined.

Plants under a Microscope

My portfolio for my practicals in Diversity of life 1 I have to draw prepared angiosperm sections. I have to draw and fully annotate the following: root, shoot, stem, leaf, inflorescence and epidermis. the rest of the portfolio will be doing the same for some gymnosperm tissue sections and then for some algae and lower plant live cultures. the second part will be writing about the plant life cycle using rapid cycling brassicas.

Meanwhile doing the drawings of the Angiosperm sections I took some pictures down the microscope. 

(Above; l.s Inflorescence, 4x/0.10)

 (Above; t.s leaf, 10x/0.22)

(Above; l.s root tip, 4x/0.10)

(Above; l.s tangenial stem, 4x/0.10)

(Above; l.s radial stem, 4x/0.10)

(another stem that I looked at but didn't use for my portfolio.)

...and now to get on with all this drawing...

Crayfish Dissection

One of my first practical’s for my module 'Diversity of Life 2' was to dissect crayfish. This module covers the diversity of the invertebrates. Half of the module is arthropods and the other half is on everything else...

In college I had dissected a fair few of the basic things like pigs hearts, lungs, frogs, rats and even an octopus but nothing to the skill in which I would need for my degree. It was fairly straight forward, and it was very interesting. I learnt that putting it underwater after the initial dissection enabled me to see things more clearly for example its gills. 

I also had to do a two detailed scientific diagrams; one of the external dorsal view of the crayfish and another of the ventral internal anatomy.

A very interesting start to my degree.