taxonomic collection and identification

Taxonomic collection

Value of collection Purpose of taxonomic collection Collecting and research Scope of collection Where and how to collect Contents of collection Preservation of specimens Labeling

OUTLINES

Biological collections are highly valuable for the following reasons:

- Museums are only place where extinct species are preserved.

- specimens of special historical value.

- specimens rarely found in any collections.

- Many areas in world are geographically inaccessible.

- A material is of unique value if it forms the basis of published research.It may be needed again for verification of original data or for renewed study in the light of more recent knowledge or by new techniques.

Value of collections

For typologically oriented taxonomist a collection was an identification collection.

According to current thinking,biological classification is the ordering of populations.Collecting ,then,is the sampling of populations.

An adequate sample of every population should be collected and preserved.

Purpose of scientific collection

More material is needed in a species with strong individual and geographical variation than in a uniform species.

More material is needed for studies of specific and subspecific characters than of the characters of higher taxa.

What is adequate collection?

On the whole taxonomists spend only a small fraction of their time on the collecting of new material.

Some big expeditions of the nineteenth century gathered material that is still not yet fully worked out.

Collecting and research

Only a few large national musuems attempt worldwide coverage in all groups of animals.Most museum are largely restricted to a geographic area and to certain group.

Too broad a coverage leads to shallowness and a failure to obtain the dept required for detail studies.

Scope of collection

The late admiral H.Lynes who was especially interested in Cisticola .a genus of African warblers with some 40 species,made whole series of collecting trips to nearly every corner of Africa.He combined the collecting of specimens with a detailed study of the ecology,songs and nest construction of the birds.The result was that the genus Cisticola ,formely the despair of the bird taxonomists ,is now reasonabally well understood.

Any collecting trip must be carefully planed All possible geographic information must be

obtained before hand,including - distribution of vegetable types - altitudes - seasons - means of transportation etc

Where and how to collect?

a plotting of collecting stations and,in particular a maping of species distribution will reveal the location of crucial gaps.

If the study of geographic variation is a major objective ,the periphery of the range of each species should be given particular attention.This is where geographic isolates occur more frequently.

If the species show seasonal variations ,the collection should be spaced seasonally.

Innumerable techniques for the collecting of different groups of animals are described in standard collecting manuals.

How to collect?

Attracting Nocturnal Insects With UV Light

Insects are collected mainly by beating and sweeping

beating sweeping

Aquatic insects and other arthropods are collected by using dipnets .

Dip net

Trawling and dredging for collecting deepsea animals

Trawling Dredging

Collecting net

Killing bottles

Cyanide bottle

POISON

Preserved specimens are the indispensible basis of all taxonomic research.the information that one can derive from such specimens are limited.

The modern systematist needs a great deal of additional information.

As far as possible the collecting should provide unbiased population samples.

not only adult should be collected ,but adequate samples of all growth stages (including larvae) and associated parasites

Contents of collections.

Sampling should be done in such a way as to provide study material not only for the species but also for the evolutionist.

Collection of specimens may be augmented by all sorts of recordings including

Film of courtship display Vocalization of animals Collections or photograph or casts of the

work of animals(nests,galls,spider webs etc)

They differ from one taxonomic group to the next. Some are preserved in alcohol. Some are stuffed We do not use formalin for preserving arthropods,

only vertebrates. Specimens are not kept permanently in formalin since it is acidic and difficult to handle.

Although generally avoided for long-term storage, formalin may be used in instances where colour is important since alcohol dissolves most colours almost immediately.. Alcohol - long term storage

Preservation of specimens

A specimen that is not accurately labeled is worthless for most type of taxonomic research.

RECORDING DATA

• Geographic locality

• Date

• Stage(adult male,female or immature form)

• Altitude or depth.

• Host

• Name of collector

Labeling