TOPIC 1 – CLASSIFICATION OF LIVING THINGS

TOPIC 1:

CLASSIFICATION OF LIVING THINGS

KINGDOM FUNGI

Member of the kingdom Fungi include fairly familiar organisms such as mushrooms, toadstools and bracket fungi. There are also less obvious but very important members such as mold, which grow on bread, ripe fruits and other food.

The General and Distinctive Features of the Kingdom Fungi

General features of kingdom fungi

  1. Fungi are found in damp or wet places
  2. They have eukaryotic cells.
  • They are heterotrophs, some are saprophytic where others are parasitic
  1. They store food as glycogen
  2. They reproduce using spores
  3. More are multicellular, Some are unicellular
  • Reproduce sexually and asexually
  • Cell walls are made of CHITIN

Distinctive features of kingdom fungi

  1. They have chitin in their cell wall
  2. Store excess carbohydrates in form of 
  3. Mycellium (inter woven thread like structures) made of hyphae except for yeasts.
  4. Grow in damp conditions.

The Phyla of the Kingdom Fungi

  • Ascomycota
  • Zygomycota
  • Basidiomycota

PHYLUM ASCOMYCOTA

Ascomycota are also called sae fungi. They produce spore in sae-like cell called asci. These spores are called ascopores. Examples of Ascomycota are yeast, penicillium, cup fungi and ring worm fungi.

Characteristics of phyla Ascomycota

  1. Their cell wall is not made by chitin but cetin polysaccharide component of phosphoric acid
  2. Have granulated cytoplasm
  3. Store food in form of glycogen
  4. Reproduce asexually by budding and sexually by means of ascospores.

Distinctive features

  • Reproduce sexually by means of ascospores

 

PHYLUM ZYGOMYCOTA

Members of this phylum produce asexual spores in structures called sporangia e.g.  Mucor, rhizopus (bread mould), (pin mould).

 

PHYLUM BASIDIOMYCOTA

Members of this phylum produce sexual structures called Basidia which produce spores called basidia spores. E.g. Mushrooms, toadstools, puffballs, rusts smuts.

Economic importance of fungi.

Useful Effects

  1. Used for food (directly) e.g. Mushrooms
  2. Used to make bread e.g. Yeast
  3. Used in production of antibiotics e.g. Pencillin
  4. Used in brewing industries e.g. Production of alcohol e.g. Yeast
  5. Production of acids e.g. Rhizopus
  6. Decomposition of organic matter, therefore adds fertility to the soil. E.g. most fungi.
  7. Used for biological study e.g. Yeast, mucor, fungi, mushrooms, rhizopus.

Harmful Effects:

  1. They cause diseases (humans, plants and animals) e.g. Smuts, rusts, candids.
  2. Some mushrooms are poisonous e.g. Amonita
  3. They spoil foods e.g. Rhizopus and mucor.
  4. They destroy furniture and building materials e.g. Rhizopus.
  5. They poison food e.g. Aspergillus

 

KINGDOM PLANTAE

General Characteristics.

  1. Have chloroplast which has chlorophyll.
  2. Multi cellular.
  3. Store extra carbohydrates in the form of starch.
  4. Have cell wall made of cellulose.
  5. The show localised growth.
  6. Show movement of curvature.
  7. Responds very slowly to stimuli.

Distinctive features

  • Show localized growth.
  • Have chloroplast.
  • Have cell wall.
  • Stores excess carbohydrates in the form of starch.

The kingdom is divided into 4 divisions:

  • Division Bryophyta
  • Division Filicinophyta
  • Division Coniferophyta
  • Division Angiospermophyta

 

 

Phylum Bryophyta

General characteristics:

  1. Are terrestrial and grow on damp areas.
  2. Do not have specialized vascular tissues.
  3. Produces gametes in structures called artheidia for male gametes and archegonia for female gametes.
  4. Shows an alteration of generation including a saprophyte generation and gamophyte generation.

Distinctive features

  1. Gametophyte generation is dominant over sporophyte generation.
  2. They lack xylem and phloem.
  3. They survive only in damp area.
  4. The gametes depends on water for fertilization e.g. Funeria (moss), Pelia (Liverwarf).

The Structure of Mosses

Mosses are small, soft plants called bryophytes, that are typically 1–10 cm (0.4–4 in) tall, though some species are much larger. They commonly grow close together in clumps or mats in damp or shady locations. They do not have flowers or seeds, and their simple leaves cover the thin wiry stems. At certain times mosses produce spore capsules which may appear as beak-like capsules borne aloft on thin stalks.

Advantage and Disadvantages of Mosses

On the advantage side, it can help to hold the bonsai soilin place and prevent it from washing out of the container. Moss can increase the water retention capability of the soil by slowing evaporation.

On the disadvantage side, a thick carpet of moss can reduce the diffusion of gases into the soil and to the roots, which can result in root rotor poor drainage conditions. Moss can grow up onto the surface roots and trunk of your bonsai, and soften their bark, promoting its decay.

 

Division Filicinophyta (Pteridophyta)

General and Distinctive Features of the Division Filicinophyta

This division was formerly called Pteridophyta. The division Filicinpphyta includes a group of primitive vascular plants. The adult plant body in these plants is a sporophyte.

It shows differentiation into true roots, stems and leaves. The stem is mostly herbaceous. Leaves may be smaller or larger. Vascular tissues are present in all the vegetative parts of the plant body. Members of this kingdom include horsetails and ferns

Characteristics of division Filicinophyta

General characteristics:

  • Have simple vascular tissues.
  • Plant body is divided into roots (fibrous), stem (rhizome) and leaves.
  • Productive structures are sporangia grow on the underside of the leaves in clusters called sori.
  • They grow in damp, shady areas.
  • They have large leaves called fronds.
  • The sporophyte generation is dominant over the gametophyte generation.

Distinctive features

  1. Have large leaves called fronds.
  2. Reproductive structures grow under fronds in sporangia which occur in clusters called sori.
  3. Young leaves show a circinate fashion (rolled) (coiled) which uncoils as leaf grows to maturity. E.g. fern plant.

Economic importance of Bryophyta and Filicinophyta

  • Used in decoration (Filicinophyta)
  • Gives out oxygen which is inhaled by animals (both)
  • Used as cover plants to prevent soil erosion (both)
  • Fertilize the soil after death and decay.

The Structure of Ferns

Most ferns produce spores on the underside or margin of their leaves. Like seed plants, ferns have stems with a vascular system for efficient transport of water and food. Ferns also have leaves, known technically as megaphylls, with a complex system of branched veins.

In general, ferns consist of the following structures:

Fronds

The frond is the “leaf” of a fern. It is divided into two main parts, the stipe (leaf stalk or petiole)and the blade (the leafy expanded portion of the frond).

Rhizomes

Rhizomes would be comparable to “stems” in the flowering plants. Fronds arise from the rhizome. In some epiphytic ferns (ferns that grow on trees) and in terrestrial creeping ferns the rhizome roams widely and is quite visible.

The rhizome contains the conducting tissues (xylem and phloem) and the strengthening tissues (sclerenchyma fibres). The conducting tissue, known as the vascular bundle, carries the water, minerals, and nutrients throughout the plant.

Roots

Roots are formed from the rhizomes or sometimes from the stipe. The roots usually do not divide once they grow from the rhizome. Tree fern roots grow down from the crown and help thicken and strengthen the trunk. The roots anchor the plant to the ground and absorb water and minerals.

Sporangia

The sporangia are the reproductive structures of the ferns and fern allies. They produce the dust like spores that are the “seeds” by which ferns are propagated. Several sporangia grouped together are called a sorus. Most ferns have their sporangia on the underside of the frond, arranged in an organized pattern usually associated with veins in the pinnule (leaf).

 

Spores

The “seeds” of the ferns and fern allies are called spores. Normally they are formed in groups of four. Spores contain oil droplets and sometimes chlorophyll in their nucleus.

 

Advantages and Disadvantages of Ferns

Advantages of ferns

  1. Some ferns are edible and hence serve as a source of food.
  2. They provide nutrients to the soil to improve soil fertility.
  3. They cover the soil and prevent soil erosion.
  4. They are used as decoration materials.

Disadvantages of ferns

  1. They harbour dangerous organisms like snakes and insects.
  2. Some ferns are poisonous when eaten.
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