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Biological Responses in Context
Published in Arthur T. Johnson, Biology for Engineers, 2019
It is easier to see the interdependence of BU in sexual reproduction. We normally think of sexual reproduction as the union of a male gamete (or germ cell) with a female gamete to produce a zygote (a fertilized egg). Male gametes are usually called sperm in animals and pollen in plants. Female gametes are called eggs in both cases. Gametes are haploid because they each contain but one of the set of chromosomes found in mature individuals. Zygotes are diploid because they contain chromosomes in pairs, just as they will when they mature into adults.
The Biosphere: Environmental Biochemistry
Published in Stanley Manahan, Environmental Chemistry, 2017
Primitive single-celled organisms, particularly bacteria, undergo asexual reproduction, in which a cell simply splits to form two cells. Humans and most other multicelled organisms undergo sexual reproduction, requiring that male sperm cells fertilize female egg cells to produce cells capable of dividing and producing new individuals.
The Biosphere
Published in Stanley E. Manahan, Environmental Chemistry, 2022
Primitive single-celled organisms, particularly bacteria, undergo asexual reproduction, in which a cell simply splits to form two cells. Humans and most other multicell organisms undergo sexual reproduction, requiring that male sperm cells fertilize female egg cells to produce cells capable of dividing and producing new individuals.
Microalgae for saline wastewater treatment: a critical review
Published in Critical Reviews in Environmental Science and Technology, 2020
Hoang Nhat Phong Vo, Huu Hao Ngo, Wenshan Guo, Soon Woong Chang, Dinh Duc Nguyen, Zhuo Chen, Xiaochang C. Wang, Rong Chen, Xinbo Zhang
Each alga strain prefers a specific salinity range for its growth rate and biomass yield. For instance, green algae were detected mostly in oligohaline and mesohaline lakes, while blue-green algae were adaptable in mesohaline and polyhaline ones (Afonina & Tashlykova, 2018). The Chaetoceros calcitrans could grow in marine environments (3%) while Chlorella sp. preferred less salinity (2.5%) (Adenan et al., 2013). On the subject of growth rate, both Chlorella sp. and Chaetoceros calcitrans possessed comparable growth rates (Table 3). In the Black Sea, Ardissonea crystalline and Ardissonea sp. tolerated salinity ranging from 23% to 38% through the responses of cell size and sexual reproduction (Davidovich, Davidovich, Podunay, Shorenko, & Witkowski, 2016). The species Gracilaria tenuistipitata and Enteromorpha intestinalis acclimatized at a low salinity level of 20 psu (Elfwing & Tedengren, 2002). Furthermore, Shewanella sp. could tolerate a wide range of salinity from 0% to 7%, so that the biomass concentration increased correspondingly from 0.04 to 0.36g/L (Meng, Liu, Zhou, & Fu, 2014). It is therefore evident that among microalgae species, the salinity range can vary markedly. For example, Shewanella sp. is likely to adjust to the largest salinity spectrum from fresh (0%) to an extreme halophilic value (7%).
Algae and their growth requirements for bioenergy: a review
Published in Biofuels, 2021
Sharifah Najiha Badar, Masita Mohammad, Zeynab Emdadi, Zahira Yaakob
More recently, the discovery of the potential of algae has attracted a lot of attention, and has led to new findings that offer an alternative way to replace fossil fuels. The ‘algae’ include a very large and diverse group of photosynthetic, plant-like organisms of various sizes and shapes, ranging from unicellular to multicellular forms. True algae are eukaryotes which have numerous membrane-enclosed structures including nuclei and chloroplasts. Most of them are multicellular, but plenty are unicellular. Algae exhibit a wide range of reproductive strategies: vegetative [1], simple asexual cell division [2] and complex sexual reproduction [3]. However, they lack many distinct cells and organs found in terrestrial plants such as stems, leaves, true roots, and vascular tissue [4]. The simpler structures of algae compared to green land plants allows them to grow rapidly and become widely distributed in marine and freshwater environments [5,6]. The presence of chloroplasts enables algae to manufacture their own food by photosynthesis. Algae in the family Characeae (a group of charophytes) are believed to be the closest relatives of green land plants [7]. They superficially resemble the stem-like and leaf-like structures of horsetail ferns [8]. The photosynthetic mechanism in algae is similar to that in terrestrial plants [9], which need water, carbon dioxide (CO2) and nutrients, and which produce oxygen as a by-product. However, they are able to capture a large fraction of solar energy, more efficiently than land plants, and can effectively utilise CO2 from the surrounding air [5,10]. The cultivation of algae is environmentally friendly [11] and can be performed in a wide range of conditions. Algae require simple accommodation, do not require fertile agricultural land and can be cultivated in water that is not suitable for human consumption [12,13].