Algal Sentence Examples

It may be regarded as derived from a wholly dependent sporogonium not unlike that of some of the simpler Bryophyta; the latter are assumed to have arisen from primitive Algal forms, in which, as the first step in the interpolation of the second generation in the life cycle, the fertilized ovum gave rise to a group of swarm spores, each of which developed into a new sexual plant.

Some forms, however, such as " Sarcina," have their algal analogues in Palmellaceae among the green algae, while Thaxter's group of Myxobacteriaceae suggests a relationship with the Myxornycetes.

The algal fungi, Phycomycetes, are obviously derived from the Green Algae, while the remaining Fungi, the Eumycetes, appear to have sprung from the same stock as the Rhodophyceae.

The soredia are the most successful method of reproduction in lichens, for not only are some forms nearly always without spore-formation and in others the spores laregly abortive, but in all cases the spore represents only the fungal component of the thallus, and its success in the development of a new lichen-thallus depends on the chance meeting, at the time of germination, with the appropriate algal component.

In these forms gonidia are found in connexion with the young fruit; such algal cells undergo numerous divisions becoming very small in size and penetrating into the hymenium among the asci and paraphyses.

The algal cells are usually controlled in their growth by the hyphae and are prevented from forming zoospores, and in some cases, as already described, the algal cells are killed sooner or later by the fungus.

Most systems agree in deriving the major divisions from the characters of the reproductive organs (perithecia, apothecia, or basidiospore bearing fructification), while the characters of the algal cells and those of the thallus generally are used for the minor divisions.

A more important consideration is the occasional absence of this colour in species, or groups of species, with, in other respects, algal affinities.

They undoubtedly represent the lowest grade of algal life, and their distribution rivals that of the Green Algae.

The experiment of Engelmann referred to deserves to be mentioned here, if only in illustration .of the use to which algae have been put in the study of physiological problems. Engelmann observed that certain bacteria were motile only in the presence of oxygen, and that they retained their motility in a microscopic preparation in the neighbourhood of an algal filament when they had come to rest elsewhere on account of the exhaustion of oxygen.

There can be little doubt of the Algal nature of the fossil, but beyond this it is impossible at present to carry its determination.

The problem of algal blooms may need to be resolved.

The Plan calls for a coordinated response to support state and local efforts during events such as outbreaks of harmful algal blooms.

The problems are not confined to land; there are also concerns about algal toxins in fish and the chemicals used in fish farming.

The algal fungi, Phycomycetes, are obviously derived from the Green Algae, while the remaining Fungi, the Eumycetes, appear to have sprung from the same stock as the Rhodophyceae (see FUNGI).

Collemaceae); in these the algae are Chroococcaceae and Nostocaceae, and the fungus makes its way into the gelatinous membranes of the algal cells and ramifies there (fig.

The fungus seems, on the other hand, to stimulate the algal cells to special development, for those in the lichen are larger than those in the free state, but this is not necessarily adverse to the idea of parasitism, for it is well known that an increase in the size of the cells of the host is often the result of the attacks of parasitic fungi.

The conceivable variations in the conditions which would count in algal life are variations in the chemical character of the water - whether fresh, brackish or salt; or in the rate of movement of the water, whether relatively quiet, or a stream or a surf; or in the degree of illumination with the depth and transparency of the water.

This physical stratification is the primary requisite for the development of algal blooms in the Tidal Lagan, as nutrients are rarely limiting.

North Isles scallop fishing ban The first outbreak of algal bloom in Orkney this year to produce shellfish toxins was reported at the weekend.

Careful hunting in the limestone revealed examples of the algal laminations and small domed stromatolites discovered by Margaret Wood and colleagues in the 70s.

This means the term " algal " stromatolite reef is no longer current scientific usage.

Partially submerged caves around Thanet vary considerably in depth, height and aspect and hence in the algal communities present.

This broken down waste often runs off into streams, lakes, rivers and oceans causing algal blooms.

This is an important feature since an overabundance of fertilizers washing into waterways can cause harmful algal blooms.

This is especially the case in the lichens (symbiotic organisms composed of a fungal mycelium in association with algal cells), which are usually exposed to very severe fluctuations in external conditions.

The fungal part of the organism nearly always consists of a number of the Discomycetes or Pyrenomycetes, while the algal portion is a member of the Schizophyceae (Cyanophyceae or Blue-green Algae) or of the Green Algae; only in a very few cases is the fungus a member of the Basidiomycetes.

The special fungi which take part in the association are, with rare exceptions, not found growing separately, while the algal forms are constantly found free.

The algal cells are never known to form spores while part of the lichen-thallus, but they may do so when separated from it and growing free.

The view of the dual nature of lichens had hitherto been based on analysis; the final proof of this view was now supplied by the actual synthesis of a lichen from fungal and algal constituents.

Moller also in 1887 succeeded in growing small lichen-thalli without their algal constituent (gonidia) on nutritive solutions; in the case of Calicium pycnidia were actually produced under these conditions.

Since they are provided with both fungal and algal elements, they are able to develop directly, under suitable conditions, into a new thallus.

When the spores germinate the germ-tubes surround the algal cells, which now increase in size and become the normal gonidia of the thallus.

Theoretically the lichens may be classified on the basis of their algal constituent, on the basis of their fungal constituent, or they may be classified as if they were homogeneous organisms. The first of these systems is impracticable owing to the absence of algal reproductive organs and the similarity of the algal cells (gonidia) in a large number of different forms. The second system is the most obvious one, since the fungus is the dominant partner and produces reproductive organs.

Considering, however, that it is generally believed that Bryophyta and vascular plants are descended from an algal ancestry, it is natural to suppose that, prior to the luxuriant vegetable growths of the Carboniferous period, there must have existed an age of algae.

It may even be regarded as an open question whether some of them may not have arisen independently and represent parallel lines of evolution from Bryophytic or Algal forms. This leads us to consider the question whether any indications exist as to the manner in which the Pteridophyta arose.

Apart from the multitude of supposed fossil Algae described as " Fucoids " but usually not of Algal nature, and never presenting determinable characters, very little remains that can be referred to Palaeozoic Brown Algae.

Carruthers, however, in 1872 established its Algal nature, and gave it the more appropriate name of Nematophycus.

No recognizable plant-remains, if we accept one or two doubtful Algal specimens, have so far been yielded by the Cambrian.