Green Algae are placed in the Protista while plants are placed in a separate kingdom because Plants enclose and protect the embryo within the seed, while green algae do not.
Algae are difficult to define. Difficulty in classifying algae is determining whether they are Protista, plants, or whether they merit their own kingdom. Different classification systems answer this question in different ways, with some even splitting the group between the kingdoms Protista and Plantae.
Green algae can be either unicellular or multicellular. They live mostly in fresh water, but some can live on land in moist soils. A few green algae are found in marine environments. These organisms often live symbiotically with aquatic and marine animals. They are of particular interest because the group from which land plants evolved, the charophyta, are green algae.
The green algae are often classified in the Kingdom Plantae, based on two characteristics shared with higher plants:
- Green algae use chlorophyll a and b in photosynthesis.
- The chloroplasts of green algae are enclosed in a double membrane.
This second characteristic indicates that the chloroplasts evolved from endosymbiosis of a prokaryote, as is the case with higher plants. Also, analysis of genetic material indicates a high degree of relatedness between green algae and terrestrial plants.
Haploid spores give rise to a multicellular haploid leaf-like structure called a thallus. The thallus produces gametes. Green algae are isogamus, meaning they have only one type of gamete, rather than having separate male and female gametes. When two gametes meet, fertilization takes place and a diploid zygote is formed. The zygote then germinates, undergoes meiosis and forms haploid spores. The diploid phase of the life cycle is brief and unicellular. There are a few exceptions this general life cycle, such as the Ulva (sea lettuce), which has a multicellular diploid phase similar to that found in brown algae.
Learn more about Green Algae here : brainly.com/question/881038
#SPJ4
