Monera, Algae, Fungi, Plants, and Animals: Key Traits
Monera
Monera are bacteria. They have naked DNA, no defined nucleus or cell organelles, and a complex cell wall. They occupy all kinds of habitats.
Morphology of Bacteria:
- Cocci: These bacteria have a spherical morphology. They may appear singly or grouped in pairs, or in the form of linear or branched chains.
- Bacilli: These bacteria have an elongated morphology. They can appear isolated or in associated chains.
- Curved Bacteria: These bacteria are curved and can be of three types:
- Vibrios: if they have a single curvature.
- Spirilla: if they are wave-shaped.
- Spirochetes: if they have several bends.
Monera can be autotrophic or heterotrophic.
Algae
Algae have no separate body or a similar body structure.
- Unicellular Algae: They have chloroplasts, a cellulose cell wall, and flagella. They are aquatic and have sexual and asexual reproduction with a haplontic life cycle. Diatoms belong to this group.
- Multicellular Algae: They present a very simple organization with no real defined tissues or organs; this is called a thallus. They live in aquatic or wet environments and do not have transportation systems. They contain chlorophyll and accessory photosynthetic pigments, and have a cell wall made of cellulose. Their energy reserve is starch. Algae reproduce asexually and sexually, and present a range of life cycles.
Types of Multicellular Algae:
- Green Algae (Chlorophyta Division): They are marine and freshwater algae. They contain chlorophyll and are found in the most superficial layers.
- Brown Algae (Phaeophyta Division): They are marine algae. Besides chlorophyll, they contain fucoxanthin.
- Red Algae (Rhodophyta Division): They are marine algae and live deeper than other algae. They have phycoerythrin, a pigment capable of absorbing blue light radiation.
Fungi
Types of Fungi:
- Zygomycetes: Their hyphae lack tabikes (septa).
- Deuteromycetes: Their hyphae are septate. They have no known sexual reproduction.
- Ascomycetes: They have a mycelium with septate hyphae. They have structures called asci, which originate by fecundation. In them, meiosis occurs and haploid cells form spores. These spores develop and, after being released, give rise to a new mycelium.
- Basidiomycetes: Their hyphae are also enclosed. A characteristic of this group is the formation of structures known as basidia.
Pteridophytes
Pteridophytes have flagellated male gametes and need a moist environment. Ferns, for example, consist of roots, stems, and large leaves (fronds) in which spores form. Besides the bryophytes, they are known as cryptogams, which lack flowers.
Spermatophytae
Spermatophytae do not have flagellated gametes. They have flowers and are called phanerogams. The formation of the embryo inside the seed provides several advantages:
- It is a very effective form of resistance against desiccation and other factors that can damage the embryo.
- It contains nutrients to nourish the embryo until it develops photosynthetic capabilities.
- Seeds are an excellent way to disseminate new individuals.
Types of Spermatophytae
Gymnosperms: Characterized by having naked seeds, i.e., seeds that are not protected by a fruit. They are woody and evergreen plants, such as pine, fir, and cypress.
Angiosperms: These are the most evolved plants. Their biological success is due to the following characteristics:
- Their flowers have closed female organs within which sex cells are located.
- Seeds are housed inside a fruit.
- Their conducting vessels are more perfect than those of previous groups.
- They adapt to all types of environmental conditions: dryness, humidity, cold, etc.
They are divided into:
- Monocotyledons: Such as cereals. They are herbaceous, and their embryo has one cotyledon.
- Dicotyledons: Most common flowering plants fall into this group. They are characterized by the embryo having two structures that are converted into the first leaves.
Multicellular Eukaryotes Characteristics
- They are not autotrophs. They feed by ingestion of other organisms.
- They are mobile.
- Their cells lack a rigid wall.
- They have a diplontic life cycle.
Cnidarians
Cnidarians have a sack-shaped body open to the outside. The opening to the outside is the mouth, which communicates with the gastrovascular cavity. They are aquatic. There are two biological forms: a sedentary form (called polyps) and a floating form named jellyfish. The polyps give rise to colonies in which different individuals specialize in different functions.