General characteristics of algae

Fallowing are the some characteristics of the algae

1. Their habitat ranges from the boiling water of the hot springs to the ice cold snow covered peak mountains. The algae thrive well under all possible environmental conditions on earth.

2. The structure of algae ranges from microscopic unicellular to multicellular complex. 

3. Algae shows, vegetative, sexual and asexual type of reproduction but in cyanophyceae, sexual reproduction is completely absent.

4. Vegetative reproduction takes place by fragmentation which is accomplished by separation of group of living cells from the parent plant. The detached portion, the fragment, develops into a new plant. The fission is another method of vegetative reproduction in algae.

5. Under favorable environmental conditions the algae reproduce asexually by producing zoospores, aplanospores, hypnospores, akinetes, autospores, endospores or cysts etc.

6. Under unfavorable conditions the algae reproduce sexually. This process categorized into two types Isogamous and Heterogamous.

7. In isogamous type both male and female gametes are morphologically similar but physiologically different.

8. In heterogamous type Male and female gametes are both morphologically and physiologically different. The male gametes are usually smaller in size.

9. In isogamous and anisogamous type fertilization takes place outside the gametangia this process is known as external fertilization. Where is in Oogamous type fertilization takes place inside the gametangia this process is called internal fertilization.

10. Alternation of generation seen in the lifecycle of algae. The sporophytic phase generation is dominant and the gametophytic phase is lasts for short time in the lifecycle of algae.

11. Germination may be direct or indirect. In direct type the germination, the zygote after meiotic division develops into a new plant without producing any spores. Where as in Indirect type spores are formed and each spore develops into a new plant body.