2018年5月11日 · Chlorophyta (green algae) Division of algae which are typically green in colour. In common with higher land plants, green algae include chlorophylls a and b among their principal pigments, have cellulose as the main constituent of cell walls, and form food reserves of starch. Consequently it is believed that the ancestors of land plants must ...

2018年6月27日 · Historically, cyanobacteria were classified with plants and called blue-green algae, although true algae are eukaryotic. Cyanobacteria appear early in the fossil record with some examples approximately 3.5 billion years old. Stromatolites are large, often fossilized colonies of cyanobacteria that build up layer upon layer.

2018年5月18日 · Algae in Plant Evolution Photosynthetic protists (commonly called algae) are a diverse group of organisms and are divided into several phyla. Many are unicellular, including most euglenoids (phylum Euglenophyta) and dinoflagellates (Dinophyta), and some diatoms (Bacillariophyta) and green algae (Chlorophyta).

2018年6月11日 · dinoflagellates A division (Dinoflagellata) of protists that are heterotrophs but closely allied to brown algae and diatoms (they are sometimes classified as algae). Many have brown or yellow chromoplasts containing xanthophyll and chlorophylls a and c; others are colourless. Typically, dinoflagellates have two flagella, one propelling water to ...

2018年5月23日 · Ecologically vital, algae account for roughly half of photosynthetic production of organic material on Earth in both freshwater and marine environments. Algae exist either as single cells or as multicellular organizations. Diatoms are microscopic, single-celled algae that have intricate glass-like outer cell walls partially composed of silicon.

2018年6月27日 · Algae are responsible for over half of the oxygen produced by photosynthesizing organisms. Many forms of algae look like plants, but they differ in many ways. Algae do not have roots, stems, or leaves. They do not have the waxy cuticle plants have to prevent water loss. As a result, algae must live in areas where water is readily available.

2018年5月21日 · The amoeba, for example, is capable of detecting chemicals given off by potential food particles such as diatoms, algae, bacteria, or other protozoa. As the cell wall has no definite shape, the cytoplasm can extrude to form pseudopodia (Greek: pseudes , false; pous , foot) in various sizes and at any point of the cell surface.

2018年6月27日 · Cryptomonads themselves are the evolutionary result of endosymbiosis, and are chimeric species that evolved from ancestral red algae and a non-photosynthetic host that retained the red alga nucleus under the form of a bead-like nucleomorph chromosome. The highly condensed chromosome of this Pyrrophyta consists of three different bead-like ...

2018年5月29日 · Chloroplast — Green organelle in higher plants and algae in which photosynthesis occurs. Domain — One of the three primary divisions of all living systems: Archae, Bacteria, or Eukaryota. Enzyme — Biological molecule, usually a protein, which promotes a biochemical reaction but is not consumed by the reaction.

2018年5月29日 · The word amoeba comes from a Greek word meaning "to change." The amoeba moves by continually changing its body shape, forming extensions called pseudopods (false feet) into which its body then flows. The pseudopods also are used to surround and capture food — mainly bacteria, algae, and other protozoa — from the surrounding water. An ...