Volvox: A Type of Green Algae
Volvox is a freshwater algae which is found in ponds, ditches and
even in shallow puddles. Volvox is nothing but a chlorophyte or a green
algae which exists as a grand spherical colony. Each little algae within the
colony holds two flagella, whip-like hair. The flagella act like tails and help
them move through the water. It is interesting to watch the spinning
movement of volvox under water. They move fast and protect themselves
from the enemies (rotifers). The algae are connected to each other by thin
strands of cytoplasm which help the whole colony to swim in an organized
manner. Every algae has a small red eye-spot which enables the algae to
detect light and helps swim towards light. Volvox belongs to the family
volvocaceae, kingdom plantae and phylum chloroplyta. Here are some
interesting volvox facts.
Appearance: Numerous flagellate cells (around 50,000 ) form a volvox
colony. Volvox can be green, golden brown, red, or brown. The cells look
like 'chlamydomonas' (a genus of green algae). A hollow sphere called
'coenobium', which contains an extracellular matrix made of a gelatinous
'glycoprotein', holds the cells. One of the amazing volvox facts is that mature
volvox colonies have a front and rear end. You may call them 'north and
south pole', since volvox resembles a planet. The eye-spots are prominent in
the northern region. This makes volvox quite unique.
Habitat: You can find volvox in deeper ponds, lagoons and ditches, which
receive an abundance of rainwater. In 1700, Antonie van Leeuwenhoek, a
Dutch tradesman, known as the 'father of microbiology', discovered and
described 'volvox'.
Volvox are comparatively easy to detect. They are likely to be found in
clean nutrient rich water and they grow well in warm weather. So, summer is
the time to find volvox. You can also find them by squeezing pond scum.
Observe a jar of pond water and you will find them swimming towards light.
Because of their tendency of swimming towards light, you can easily find
them near the surface. Volvox colonies are often visible with naked eye.
Volvox is considered as one of the seven wonders of the micro world;
because of the unusual 'planetary movement' and interesting methods of
reproduction.
Reproduction: An asexual colony includes both somatic (vegetative) cells,
which do not reproduce, and gonidia near the posterior, which produce new
colonies through repeated division. The daughter colonies are initially held
within the parent coenobium and have their flagella directed inwards. Later,
the parent disintegrates and the daughters invert. In sexual reproduction two
types of gametes are produced. Volvox species can be monoecious or
dioecious. Male colonies release numerous microgametes, or sperm, while in
female colonies single cells enlarge to become oogametes, or eggs.
Food: The flagella help find mineral nutrients like phosphates and nitrates in
the surrounding environment (ponds or lakes). Volvox absorb these nutrients
that promote growth and reproduction. Volvox consume plants, bacteria and
other organic matter. They prepare their food with the help of
photosynthesis.