2018年6月11日 · Algae (singular: alga) are photosynthetic, eukaryotic organisms that do not develop multicellular sex organs. Algae can be unicellular, or they may be large, multicellular organisms. Algae can occur in salt or fresh waters, or on the surfaces of moist soil or rocks. The multicellular algae develop specialized tissues, but they lack the true ...

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5月11日 · Xanthophyta (yellow-green algae) A division of algae in which the chloroplasts are yellow-green and which form motile cells with 1 long, forward-directed tinsel flagellum and 1 much shorter, backward-directed whiplash flagellum. These …

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6月27日 · The golden algae (Chrysophyta) and brown algae (Phaeophyta) include many familiar seaweeds easily found on rocky coasts. Kelp is a gigantic marine brown alga ( Macrocystus ) that grows up to 30 meters (100 feet) long …

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5月17日 · Chlorophyll (KLOR-uh-fill) is the pigment that gives plants, algae, and cyanobacteria their green color. The name comes from a combination of two Greek words, chloros, meaning "green" and phyllon, meaning "leaf." Chlorophyll is the substance that enables plants to create their own food through photosynthesis. At least five forms of chlorophyll ...

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5月21日 · siphonaceous (siphoneous) Applied to algae in which the thallus is not divided up by septa, i.e. the many nuclei are not compartmentalized into cells. The typical siphónaceous alga has a large central vacuole surrounded by a layer of protoplasm , containing nuclei and chloroplasts , which lines the cell wall .