what are lichens
TRANSCRIPT
Studying Lichens
By
Doing Some Research
At The Melitensia
At The University Of Malta.
Lichens are common organisms that grow in
the most unusual places including bare rock and
walls, even in urban areas.
Where do we find lichens?Where do we find lichens?
About 200 lichens have been
recorded in the Maltese islands
How many different types of lichens can be found in the Maltese Islands?How many different types of lichens can be found in the Maltese Islands?
Lichens are unusual because each species is
made up of two organisms, a fungus and an alga, living intimately
together.
What are Lichens? They are surely not plants. So what are they?What are Lichens? They are surely not plants. So what are they?
Their relationship gives lichens the ability to survive under harsh conditions where no other organism can
survive.
Is their relationship a beneficial one?Is their relationship a beneficial one?
In some cases the fungus and alga which make up a lichen can be
found living separately in nature but, in many cases, the two organisms have become so
dependent on each other that one cannot survive without the other.
Can they live separetely?Can they live separetely?
Lichens do not have leaves or roots and absorb nutrients
directly through their surface. This leaves them susceptible to air pollutants which ac cu mulate
in their body without being eliminated.
Lichens and PollutionLichens and Pollution
Lichens can tolerate different concentrations of pollutants with some species dying at lower levels
than others. This makes lichens excellent biomonitors and many
species are used to indicate levels of environmental pollutants.
Why are we using lichens as monitors of pollution in this project?Why are we using lichens as monitors of pollution in this project?
Many species of lichens are eaten especially in
times of famine despite the fact that they can be
difficult to digest.
Are Lichens used as a form of food?Are Lichens used as a form of food?
Many species also contain mildly toxic
compounds, although few species are
poisonous.
Are Lichens poisonous?Are Lichens poisonous?
Some species are used to produce
dyes including the pH indicator litmus.
Are Lichens used for anything else?Are Lichens used for anything else?
SYSTEMATIC LIST OF ENDEMIC LICHEN SPECIES (can only be found in Malta)
1.Biatora fusco-nigrescens Jatta
2.Caloplaca marmorata Bagi cephaloidea Jatta in Sommier & Caruana
Gatto
3.Caloplaca melitensis Jatta
4.Caloplaca pyracea (Ach.) Th. lactea Mass. macrocarpa Jatta
5.Collema meliteum Jatta conglomeratum Jatta
6.Graphina sophistica Nyl. melitense Jatta in Sommier & Caruana Gatto
7.Lecaniella alocyza Mass. flavidula Jatta
8.Lecanora sublentigera Jatta
9.Lecidea pertusariicola Jatta
10.Scolicosporium doriae Baglietto decussatum Jatta
11.Thalloedema mammillare (Fr.) Mass. pulchella Jatta
12.Thalloedema paradoxum Jatta
Caloplaca sp., a distinctive yellow lichen which covers bare rock
Ramalina durieui, found mostly on thin branches of pine (Pinus halepensis) and
cypress (Cupressus sempervirens)
Another 'leafy', cypress-loving species
This lichen appears to prefer dead bark of the pine tree
A white lichen on a rock